JP6792971B2 - Bidirectional DC-DC converter device and its control method - Google Patents

Description

The present invention relates to a small-sized bidirectional DC-DC converter device having high conversion efficiency and a control method thereof.

In recent years, for example, a photovoltaic power generation system is equipped with a bidirectional DC-DC converter device capable of bidirectional power conversion and improved conversion efficiency. In this bidirectional DC-DC converter device, it is generally effective to use a switching element having a fast switching characteristic in order to realize small size and high conversion efficiency.

However, even if a high withstand voltage MOSFET is used as a switching element for exchanging high voltage DC power supply and power and achieving compactness and high conversion efficiency, the reverse recovery characteristic of the body diode connected to the MOSFET is the MOSFET. Since it is slower than the switching characteristics of, it is an obstacle to compactness and high conversion efficiency.

Therefore, as a well-known technique for improving the poor reverse recovery characteristics of the body diode connected to the MOSFET, a compact and highly efficient insulated "bidirectional DC-DC converter and its control method" (see Patent Document 1). Can be mentioned.

Japanese Patent No. 4643695

The technique according to Patent Document 1 described above is a cathode between a first DC power supply in a bidirectional DC-DC converter (for example, regarded as a high-voltage side DC power supply) and a DC terminal of a first switching circuit connected thereto. A DC link switch consisting of a diode inserted in series so as to face the positive current of the first DC power supply and a switching element connected in parallel to the diode is interposed, and the first DC power supply to the second DC by a control means. When supplying power to a power source (for example, regarded as a low-voltage side DC power source) (when the charging operation is stepped down), the DC link switch is kept on, and power is supplied from the second DC power source to the first DC power source. At times (during boosting of the discharge operation), the DC link switch is kept in an off state, and control is performed so as to prevent backflow of power from the first DC power source in the first switching circuit.

However, in the case of the bidirectional DC-DC converter according to Patent Document 1, the current flowing from the second DC power supply to the first DC power supply becomes a pulse shape by turning off the DC link switch at the time of boosting the discharge operation. Although the influence of the body diode connected to the MOSFET (for example, N-channel MOSFET) in the first switching circuit can be suppressed, the loss due to the influence of the body diode connected to the MOSFET (for example, N-channel MOSFET) in the second switching circuit can be suppressed. The fact is that the conversion efficiency is not so improved because it is large and a diode (for example, a fast recovery diode) connected to the switching element (for example, NPN transistor) of the DC link switch causes a loss. is there.

The present invention has been made to solve such a problem, and the technical problem is that the conversion efficiency at the time of boosting the discharge operation of supplying power from the low-voltage side DC power supply to the high-voltage side DC power supply is improved as much as possible. A bidirectional DC-DC converter device and a control method thereof.

In order to solve the above technical problem, in the first embodiment of the present invention, the rectification process is performed according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply. a switching circuit, while being interposed between the DC terminal of the said high-voltage DC power supply first switching circuit and a cathode serially inserted diode and the diode so as to face the positive electrode of the high voltage DC power supply Rectification processing according to the switching operation of a DC link switch consisting of switching elements connected in parallel and a switching element with multiple body diodes including a smoothing capacitor connected in parallel with a smoothing inductor interposed in the low-voltage side DC power supply. a second switching circuit for performing, connected between AC terminals of the first primary winding and said second switching circuit connected with intervening resonance choke coil between the AC terminals of the switching circuits 2 and a transformer that magnetically couples the following winding, to control the switching operation in said first switching circuit and said second switching circuit, a control unit for performing on-off control of the switching element of the DC link switch In a bidirectional DC-DC converter device including, the DC link switch includes a high-pressure side zero-th switching element as the switching element, and the first switching circuit is the switching element with a plurality of body diodes. The high-pressure side first switching element and the high-pressure side fourth switching element, which are one pair of switching elements arranged diagonally, and the high-pressure side first switching element, which is the other pair of switching elements arranged diagonally. The second switching circuit includes two switching elements and a third switching element on the high pressure side, and the second switching circuit is a low pressure side which is one pair of switching elements arranged diagonally as the switching elements with a plurality of body diodes. The first switching element and the fourth switching element on the low pressure side, the second switching element on the low pressure side and the third switching element on the low pressure side, which are the other pair of switching elements arranged diagonally, were connected to the smoothing capacitor. A low-pressure side zero-switching element is provided, and the control unit comprises the high-pressure side first switching element and the high-pressure side fourth switching at the time of boosting power from the low-pressure side DC power supply to the high-pressure side DC power supply. The element and the zeroth switching element on the low pressure side are The high voltage side second switching element, the high voltage side third switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, and the low voltage side fourth. From the state where the switching element is on, the voltage of the low voltage side zero switching element becomes 0V, and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side After switching the third switching element off, the high voltage side zero switching element is switched on at the first timing of switching the high voltage side first switching element and the high voltage side fourth switching element on. To do.

Further, in order to solve the above technical problem, in the second embodiment of the present invention, rectification processing is performed according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply. 1 of the switching circuit, a D C link switch that will be interposed between the DC terminal of the said high-voltage DC power supply first switching circuit, connected in parallel with intervening smooth inductor relative low voltage DC power supply connected plurality of the second switching circuit for performing rectification in accordance with the switching operation of the body diode with a switching element, between the AC terminals of the first switching circuit by interposing the resonance choke coil comprising a smoothing capacitor which is and a transformer that magnetically coupled primary winding and a secondary winding connected between AC terminals of the second switching circuit, the first of the switching in the switching circuit and the second switching circuit controls the operation, in the bidirectional DC-DC converter apparatus and a control unit for performing on-off control of the switching element of the DC link switch, the DC link switch, the cathode of the high voltage DC power supply positive The first diode inserted in series so as to face the first diode, the first zero switching element on the high pressure side connected in parallel to the first diode, and the second one inserted in series so that the cathode faces the positive electrode of the DC power supply on the high pressure side. A diode and a high-voltage side second zero switching element connected in parallel to the second diode are provided, and the first switching circuit is arranged diagonally as the plurality of switching elements with body diodes. High-voltage side first switching element and high-voltage side fourth switching element, which are a pair of switching elements, and the other pair of switching elements, high-voltage side second switching element and high-voltage side third switching element, which are arranged diagonally. The second switching circuit comprises, as the plurality of switching elements with body diodes, one pair of switching elements arranged diagonally, a low-voltage side first switching element and a low-voltage side fourth switching. A low-voltage side second switching element and a low-voltage side third switching element, which are the other pair of switching elements arranged diagonally, and a low-voltage side first zero switching element connected in parallel to the smoothing capacitor. And a low-voltage side second zero switching element, and the control unit is the low-voltage side DC power supply. At the time of boosting to supply power to the high-voltage side DC power supply, the high-voltage side second switching element, the high-voltage side third switching element, the low-voltage side first switching element, the low-voltage side second switching element, and the low-voltage side. The third switching element, the low voltage side fourth switching element is on, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first zero switching element, and the low voltage side second zero switching element. From the off state, the voltage of the low voltage side second zero switching element becomes 0V, the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side first. (3) After switching the switching element off, the high voltage side second switching element, the high voltage side fourth switching element, and the low voltage side second zero switching element are switched on at the first timing. It is characterized by switching the zero switching element on .

Further, in order to solve the above technical problem, the third embodiment of the present invention is the control method of the bidirectional DC-DC converter device having the configuration according to the first embodiment, wherein the DC link switch is the switching element. The high-voltage side first switching element is provided as a high-voltage side zero switching element, and the first switching circuit is one pair of switching elements arranged diagonally as the plurality of body diode-equipped switching elements. The second switching circuit includes a fourth switching element on the high voltage side and a second switching element on the high voltage side and a third switching element on the high voltage side, which are the other pair of switching elements arranged diagonally. As the switching elements with a plurality of body diodes, one pair of switching elements arranged diagonally, the first switching element on the low voltage side and the fourth switching element on the low voltage side, and the other pair arranged diagonally. The low-voltage side second switching element and the low-voltage side third switching element, which are the switching elements of the above, and the low-voltage side zero-th switching element connected to the smoothing capacitor, and the control unit is said to be from the low-voltage side DC power supply. At the time of boosting to supply power to the high-voltage side DC power supply, the high-voltage side first switching element, the high-voltage side fourth switching element, and the low-voltage side zero-switching element are off, and the high-voltage side second switching element, From the state in which the high-voltage side third switching element, the low-voltage side first switching element, the low-voltage side second switching element, the low-voltage side third switching element, and the low-voltage side fourth switching element are on, the low-voltage side After the voltage of the zeroth switching element becomes 0V and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side third switching element are switched off, the above It is characterized by including a step of switching the high-voltage side zero-th switching element on at the first timing of switching the high-voltage side first switching element and the high-voltage side fourth switching element on .

In addition, in order to solve the above technical problem, in the fourth embodiment of the present invention, in the control method of the bidirectional DC-DC converter device having the configuration according to the second embodiment, the DC link switch has a cathode. The first diode inserted in series so as to face the positive voltage of the high-voltage side DC power supply, the high-voltage side first zero switching element connected in parallel to the first diode, and the cathode so as to face the positive voltage of the high-voltage side DC power supply. A second diode inserted in series with the second diode and a second zero switching element on the high voltage side connected in parallel to the second diode are provided, and the first switching circuit is paired as the switching element with a plurality of body diodes. The high-voltage side first switching element and the high-voltage side fourth switching element, which are one pair of switching elements arranged in the angular direction, and the high-voltage side second switching element, which is the other pair of switching elements arranged in the diagonal direction. The second switching circuit includes the third switching element on the high voltage side and the third switching element on the low voltage side, which is one pair of switching elements arranged diagonally as the switching element with a plurality of body diodes. The low-voltage side fourth switching element and the low-voltage side fourth switching element, and the other pair of switching elements arranged diagonally, the low-voltage side second switching element and the low-voltage side third switching element, are connected in parallel to the smoothing capacitor. The first zero switching element on the side and the second zero switching element on the low voltage side are provided, and when the control unit supplies power from the low voltage side DC power supply to the high voltage side DC power supply, the high voltage side first Two switching elements, the high voltage side third switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, the low voltage side fourth switching element are on, the high voltage side first. From the state where the switching element, the high voltage side fourth switching element, the low voltage side first zero switching element and the low voltage side second zero switching element are off, the voltage of the low voltage side second zero switching element is 0V. After switching off the high-voltage side second switching element, the high-voltage side third switching element, the low-voltage side second switching element, and the low-voltage side third switching element, the high-voltage side first switching element, said. At the first timing of switching on the high voltage side fourth switching element and the low voltage side second zero switching element, the high voltage It is characterized by including a step of switching on the side second zero switching element .

According to the present invention, the conversion efficiency at the time of boosting the discharge operation of supplying power from the low-voltage side DC power supply to the high-voltage side DC power supply can be improved as much as possible by the above configuration and processing process. Issues, configurations and effects other than those described above will be clarified by the following description of the embodiments.

It is a schematic block diagram which showed the basic structure of the bidirectional DC-DC converter apparatus which concerns on this invention. It is a schematic block diagram which showed the circuit structure of the main part in the bidirectional DC-DC converter apparatus which concerns on Example 1 of this invention, and the flow of the electric current accompanying the main function control. FIG. 5 is a schematic block diagram showing a circuit configuration of a main part in the bidirectional DC-DC converter device shown in FIG. 2 and a current flow associated with other main function controls. 3 is a timing chart showing a waveform of a switching operation control signal for each switching element and a waveform of a voltage of each switching element at the time of boosting the discharge operation of the bidirectional DC-DC converter device shown in FIG. 2 or FIG. It is a timing chart which shows the waveform of the current of each switching element, and the waveform of the current and voltage in each device at the time of boosting the discharge operation of the bidirectional DC-DC converter apparatus shown in FIG. 2 or FIG. It is a schematic block diagram which showed the circuit structure of the main part in the bidirectional DC-DC converter apparatus which concerns on Example 2 of this invention. 6 is a timing chart showing a waveform of a switching operation control signal for each switching element and a waveform of a voltage of each switching element at the time of boosting the discharge operation of the bidirectional DC-DC converter device shown in FIG. It is a timing chart which shows the waveform of the current of each switching element, and the waveform of the current and voltage in each device at the time of boosting the discharge operation of the bidirectional DC-DC converter apparatus shown in FIG. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t1 shown in FIG. 6-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t2 shown in FIG. 6-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t3 shown in FIG. 6-1. It is a figure which showed the current flow in the circuit structure of the main part of the bidirectional DC-DC converter apparatus in the period t4 shown in FIG. 6-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t5 shown in FIG. 6-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t6 shown in FIG. 6-1. 6 is a timing chart showing a waveform of a switching operation control signal and a waveform of a voltage of each switching element according to a well-known technique for each switching element at the time of boosting the discharge operation of the bidirectional DC-DC converter device shown in FIG. The current waveform of each switching element and the current and voltage waveforms of each device when the switching operation control signal shown in FIG. 8-1 is applied at the time of boosting the discharge operation of the bidirectional DC-DC converter device shown in FIG. It is a timing chart shown. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t1 shown in FIG. 8-1. It is a figure which showed the current flow in the circuit structure of the main part of the bidirectional DC-DC converter apparatus in the period t2 shown in FIG. 8-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t3 shown in FIG. 8-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t4 shown in FIG. 8-1. It is a figure which showed the current flow in the circuit composition of the main part of the bidirectional DC-DC converter apparatus in the period t5 shown in FIG. 8-1.

Hereinafter, the bidirectional DC-DC converter device of the present invention and its control method will be described in detail with reference to the drawings with reference to some examples.

First, the basic configuration of the bidirectional DC-DC converter device of the present invention will be briefly described with reference to the schematic block diagram shown in FIG.

Referring to FIG. 1, the bidirectional DC-DC converter device of the present invention has a plurality of switching elements (N) with body diodes, which will be described later, connected in parallel to the high-voltage side DC power supply (HV) 1 as a basic configuration. Channel MOSFET) A first switching circuit 3 that performs rectification processing according to the switching operation of H1 to H4 (hereinafter, simply referred to as switching elements H1 to H4), and a high-voltage side DC power supply (HV) 1 and a first switching circuit. A switching element connected in parallel to the diode (fast recovery diode) D and the diode D, which are interposed between the DC terminals of 3 and inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply (HV) 1. A switching element with a plurality of body diodes including a DC link switch 5 composed of (NPN transistor) H0 and a smoothing capacitor Cc connected in parallel to a low-voltage side DC power supply (LV) 2 with a smoothing inductor L described later interposed interposed therebetween. (N channel MOSFET) S0 to S4 (hereinafter, simply referred to as switching elements S0 to S4) between the second switching circuit 4 that performs rectification processing according to the switching operation and the AC terminal of the first switching circuit 3 will be described later. An insulating transformer T that magnetically couples the primary winding connected with the resonant choke coil Lr interposed therebetween and the secondary winding connected between the AC terminals of the second switching circuit 4 and the first in basic operation. A charging operation for the smoothing capacitor Cc that controls the switching operation in the switching circuit 3 and the second switching circuit 4 of 1 and supplies power from the high-voltage side DC power supply (HV) 1 to the low-voltage side DC power supply (LV) 2. When stepping down, the switching element H0 of the DC link switch 5 is kept on, and when the DC link is boosted, the discharge operation from the smoothing capacitor Cc that supplies power from the low-voltage side DC power supply (LV) 2 to the high-voltage side DC power supply (HV) 1 A control unit 6 for controlling the switching element H0 of the switch 5 to be kept in an off state is provided. The control unit 6 here is a discharge operation switching unit (during boosting) 6a for performing a discharging operation by switching control and a charging operation switching unit (during stepping down) 6b for performing a charging operation by switching control. A switching operation generated by pulse width modulation (PWM) of the switching elements H0 of the DC link switch 5, the switching elements H1 to H4 of the first switching circuit 3, and the switching elements S0 to S4 of the second switching circuit 4. It has a pulse width modulation (PWM) unit 6c for performing a switching operation by a control signal.

The bidirectional DC-DC converter device shown in FIG. 1 can be regarded as having substantially the same configuration as the bidirectional DC-DC converter described in Patent Document 1 in terms of basic configuration, but in the present invention, the control unit 6 provides a low-voltage side DC power supply ( Control for a bidirectional DC-DC converter device as described in each of the following examples in order to improve the conversion efficiency at the time of boosting the discharge operation of supplying power from the LV) 2 to the high-voltage side DC power supply (HV) 1 as much as possible. As a method, loss reduction control processing for reducing the loss in the second switching circuit 4 on the low-voltage side DC power supply (LV) 2 side, and conversion in the first switching circuit 3 on the high-voltage side DC power supply (HV) 1 side. Performs conversion efficiency improvement control processing that improves efficiency.

FIG. 2 is a schematic block diagram showing a circuit configuration of a main part of the bidirectional DC-DC converter device according to the first embodiment of the present invention and a current flow associated with main function control.

Referring to FIG. 2, the bidirectional DC-DC converter device here shows a circuit and a current flow of a bidirectional DC-DC converter portion which is a schematic representation of the control unit 6 shown in FIG. In the DC link switch 5, the collector terminal side of the switching element H0 is connected to the positive side of the high-voltage side DC power supply (HV) 1, and the emitter terminal side is connected to the drain terminal side of the switching elements H1 and H3 in the first switching circuit 3. , The source terminal side of the switching elements H1 and H3 is connected to the drain terminal side of the switching elements H2 and H4. Further, in the first switching circuit 3, the source terminal side of the switching elements H2 and H4 is connected to the negative side of the high-voltage side DC power supply (HV) 1, and the source terminal side of the switching element H1 and the drain terminal side of the switching element H2. A lead wire from between is connected to the primary winding of the isolation transformer T with a resonance choke coil Lr interposed therebetween, and its end is connected to the drain terminal side of the switching element H4. In the second switching circuit 4, the source terminal side of the switching element S0 is connected to the positive side of the low voltage side DC power supply (LV) 2 via the smoothing inductor L, and the drain terminal side is connected to the low voltage side DC power supply (LV) via the smoothing capacitor Cc. It is connected to the negative side of LV) 2. Further, in the second switching circuit 4, the drain terminal side of the switching elements S1 and S3 is connected to the smooth inductor L, and the source terminal side is connected to the drain terminal side of the switching elements S2 and S4. In addition, the source terminal side of the switching elements S2 and S4 is connected to the smoothing capacitor Cc and the negative electrode side of the low voltage side DC power supply (LV) 2. In addition, a lead wire from between the source terminal side of the switching element S1 and the drain terminal side of the switching element S2 is connected to the secondary winding of the isolation transformer T, and its end is connected to the drain terminal side of the switching element S4. ing.

To specifically explain the main function control of the control unit 6 with reference to FIG. 2, the switching element H0 of the DC link switch 5 is turned on for a predetermined time at the time of boosting the discharge operation, and the first switching circuit 3 The resonance choke coil is turned on by turning on one pair of switching elements H1 and H4 arranged diagonally of each switching element H1 to H4 in the above, and turning off the other pair of switching elements H2 and H4 arranged diagonally. A backflow current is passed from Lr to the switching element H0 of the DC link switch 5 via the primary winding of the insulating transformer T and the high-voltage side DC power supply (HV) 1 (indicated by a thick arrow), and the second The switching element S0 connected to the smoothing capacitor Cc in the switching circuit 4 is turned off, and one pair of switching elements S1 and S4 arranged diagonally of the switching elements H1 to H4 are turned on and arranged diagonally. A weak current (indicated by a thick arrow) in the direction opposite to the direction in which the current flows according to the generation of the backflow current in the first switching circuit 3 during the rectification process with the other pair of switching elements S2 and S4 turned off. Control is performed to reduce the switching loss in the second switching circuit 4 by flowing (indicated by a thin arrow) to cause cancellation. Specifically, it has the effect of reducing the switching loss of the switching elements S1 and S4 in the second switching circuit 4. The control function by the control unit 6 can be regarded as being executed in the loss reduction control processing step in the control method of the bidirectional DC-DC converter device. Incidentally, the backflow current in the first switching circuit 3 can be controlled by the control unit 6 by giving a timing to turn off the switching element H0 of the DC link switch 5.

FIG. 3 is a schematic block diagram showing a circuit configuration of a main part in the bidirectional DC-DC converter device shown in FIG. 2 and a current flow associated with other main function control.

With reference to FIG. 3, regarding the bidirectional DC-DC converter device here as well, the circuit and current flow of the bidirectional DC-DC converter portion, which is a schematic representation of the control unit 6 shown in FIG. 1, are shown. To specifically explain the other main function control of the control unit 6, the switching element H0 of the DC link switch 5 is turned on for a predetermined time at the time of boosting the discharge operation, and each switching element in the first switching circuit 3 is turned on. From the resonance choke coil Lr, one pair of switching elements H1 and H2 arranged diagonally of H1 to H4 are turned off, and the other pair of switching elements H2 and H3 arranged diagonally are kept on. A rectification process is performed by passing a current in the direction (indicated by a thick arrow) toward the high-voltage side DC power supply (HV) 1 via the primary winding of the insulating transformer T and the switching element H0 of the DC link switch 5. The switching element S0 connected to the smoothing capacitor Cc in the switching circuit 4 of 2 is turned on, and one pair of switching elements S1 and S4 arranged diagonally of the switching elements S1 to S4 are turned off and arranged diagonally. The other pair of switching elements S2 and S3 to be turned on is kept on, and the direction from the smoothing inductor L to the low-voltage side DC power supply (LV) 2 via the secondary winding of the insulating transformer T (indicated by a thick arrow). Control is performed to improve the conversion efficiency by performing rectification processing by passing a current through the current. Specifically, the conversion efficiency in the first switching circuit 3 can be improved by allowing a current to flow through the switching element H0, which has a smaller loss than the diode D in the DC link switch 5. The control function by the control unit 6 can be regarded as being executed in the conversion efficiency improvement control processing step in the control method of the bidirectional DC-DC converter device.

By the way, the loss reduction control process and the conversion efficiency improvement control process by the control unit 6 described with reference to FIGS. 2 and 3 are the base and the second of the switching element H0 of the DC link switch 5 at the time of boosting the discharge operation. The on / off timing of the switching operation by the switching operation control signal sent to the gates of the switching elements H1 to H4 in the switching circuit 3 of 1 and the switching elements S0 to S4 in the second switching circuit 4 has a predetermined cycle. If it is appropriately controlled in half the period, the effect of improving the conversion efficiency can be enhanced.

FIG. 4-1 shows the waveforms of the switching operation control signals for the switching elements H0 to H4 and S0 to S4 at the time of boosting the discharge operation of the bidirectional DC-DC converter device described above, and the switching operation control signals H0 to H4 and S0 to S4. It is a timing chart which shows the waveform of the voltage of. Similarly, FIG. 4-2 shows the current waveforms of the switching elements H0 to H4 and S0 to S4 at the time of boosting the discharge operation of the bidirectional DC-DC converter device, and the current and voltage (specifically, smoothing) in each device. It is a timing chart (common with FIG. 4-1 in time series) which shows the waveform of the current of the inductor L, the voltage of the insulating transformer T, the current and voltage of the resonance choke coil Lr).

With reference to FIGS. 4-1 and 4-2, the waveform of the switching operation control signal for each of the switching elements H0 to H4 and S0 to S4 initially turns on the switching elements S1 and S4 in the second switching circuit 4. The predetermined predetermined period (t1 + t2 + t3 + t4 + t5 + t6) corresponding to the period (t1 + t2 + t3 + t4 + t5 + t6) from when the switching element H0 of the DC link switch 5 is switched from off to on and then turned off again and then when the switching elements S1 and S4 are turned off. It is shown that the on / off timing is controlled as shown in the figure in the half period of the cycle.

Specifically, during the period t1, the switching element H0 of the DC link switch 5 is turned off, the switching elements H1 and H4 are kept off, and the switching elements H2 and H3 are kept on in the first switching circuit 3. By keeping the current flowing in the resonance choke coil Lr constant, the current flows in the insulation transformer T, and the switching element H2 → resonance choke coil Lr → insulation transformer T (primary winding) → switching element H3 → diode D A current flows in the direction and is supplied to the high-voltage side DC power supply (HV) 1. Further, in the second switching circuit 4, the switching element S0 is kept off, and the switching elements S1 to S4 are all kept on, which corresponds to the timing of storing energy in the smooth inductor L.

In the period t2, the switching element H0 of the DC link switch 5 is switched on, the switching elements H1 and H4 are switched on, and the switching elements H2 and H3 are switched off in the first switching circuit 3. Further, in the second switching circuit 4, the switching element S0 is kept off, and the switching elements S2 and S3 are turned off. The switching element S0 is kept off and the voltage becomes 0V, but a current flows into the smoothing capacitor Cc through the body diode.

The period t3 corresponds to the timing at which the energy stored in the smoothing inductor L is released, and by sustaining the switch setting in the period t2, the first switching circuit 3 is described with reference to FIG. A backflow current flows in the direction of switching element H0 → switching element H1 → resonance choke coil Lr → isolation transformer T (primary winding) → switching element H4, and is supplied to the high-voltage side DC power supply (HV) 1. Further, in the second switching circuit 4, a current is passed through the isolation transformer T via the switching elements S1 and S4 kept on, and the smoothing inductor L → the switching element S1 → as described with reference to FIG. Insulation transformer T (secondary winding) → Current flows in the direction of switching element S4 and is supplied to the low-voltage side DC power supply (LV) 2, and from switching element S4 to switching element S3 and from switching element S2 to switching element S1. Current also flows through the body diode in the direction of travel. At this time, in the second switching circuit 4, energy is sent through the isolation transformer T because the current of the resonance choke coil Lr is opposite in the first switching circuit 3, and the energy is sent via the switching elements S1 and S4. A weak current tries to flow in the direction opposite to the current flowing in the isolation transformer T (secondary winding) and cancels each other out, so that a loss reduction control process for reducing the switching loss is performed.

In the period t4, the switching element H0 of the DC link switch 5 is kept on, and the switch setting is maintained in the first switching circuit 3, so that the backflow current continues to flow. Further, in the second switching circuit 4, in response to the voltage of the switching elements S2 and S3 becoming 0, the switching elements S2 and S3 are turned on and the current passing through the switching elements S1 and S4 before that is switched. It also passes through the elements S2 and S3. Since the switching operation at this time is performed by zero volt switching (ZVS), no switching loss occurs.

In the period t5, the switching element H0 of the DC link switch 5 is switched off, and the backflow current stops flowing in the first switching circuit 3 even if the switch setting is maintained. Further, in the second switching circuit 4, since the switch settings are maintained and all the switching elements S1 to S4 are turned on, energy is stored in the smooth inductor L as in the case of the period t1.

In the period t6, the switching element H0 of the DC link switch 5 is kept off, and in the first switching circuit 3, the state in which the backflow current is stopped is maintained even if the switch setting is maintained. Further, since the switch setting is maintained in the second switching circuit 4, energy is continuously stored in the smoothing inductor L.

In the other half of the predetermined cycle after the period t6, the switching element H0 of the DC link switch 5 is switched on and then turned off again. At this time, in the first switching circuit 3, the switching elements H1 and H4 are switched off and the switching elements H2 and H3 are switched on and maintained. Further, in the second switching circuit 4, the switching element S0 connected to the smoothing capacitor Cc is switched on and then turned off again, the switching elements S1 and S4 are switched off and then turned on again, and the switching element S2 is switched on. , S3 is switched on and maintained. Here, the switching element H0 of the DC link switch 5 is on, the switching elements H1 and H4 in the first switching circuit 3 are off, the switching elements H2 and H3 are on, and the switching element in the second switching circuit 4 is on. When S0 is on, switching elements S1 and S4 are off, and switching elements S2 and S3 are on, in the first switching circuit 3, the switching element H2 → resonance choke coil Lr → insulation as described with reference to FIG. A current flows in a path that circulates from the transformer T (primary winding) → switching element H3 → switching element H0 to the high-voltage side DC power supply (HV) 1, and rectification processing is performed, and smoothing is performed in the second switching circuit 4. The current flows through the path that circulates from the inductor L → the switching element S3 → the insulated transformer T (secondary winding) → the switching element S2 to the low-voltage side DC power supply (LV) 2, and the rectification process is performed. Incidentally, in the rectification process in the second switching circuit 4, a current flows in both directions between the smoothing capacitor Cc and the switching element S0.

That is, in the bidirectional DC-DC converter device according to the first embodiment, the control unit 6 turns the switching element H0 of the DC link switch 5 from off to on, from on to off, and off at a predetermined cycle when the discharge operation is boosted. While repeating the operation of turning on and on and off, one pair of switching elements H1 and H4 arranged diagonally of the switching elements H1 to H4 in the first switching circuit 3 is turned from off to on and from on to on. The operation of turning off and off to on, and turning the other pair of switching elements H2 and H3 arranged diagonally from on to off and off to on is repeated, and further, the smoothing capacitor Cc in the second switching circuit 4 is used. The connected switching elements S0 are kept off and then turned on and then turned off, and one pair of diagonally arranged switching elements S1 and S4 are kept on and then turned off and then turned on. By repeating the operation of turning the other pair of switching elements S2 and S3 arranged diagonally from on to off and off to on, the above-mentioned loss reduction control process and conversion efficiency improvement control process are rectified. It can be included in the process. As a result, the smoothing inductor L current and the resonant choke coil Lr current shown in FIG. 4-2 are smaller than those in the case of boosting the discharge operation performed with the switching element H0 of the conventional DC link switch 5 turned off. It is suppressed. Further, by appropriately changing the control timing of the switching operation control signal, it is possible to always keep the conversion efficiency in the optimum state (a state close to the maximum efficiency).

Therefore, when the loss at 2.2 kW when the discharge operation was actually performed at 2.2 kW was compared with the simulation results, the discharge operation performed with the switching element H0 of the conventional DC link switch 5 turned off was 116 W. Although there was a loss, it was found that a loss of 103 W could be improved by performing a rectification process including the loss reduction control process and the conversion efficiency improvement control process according to the first embodiment.

FIG. 5 is a schematic block diagram showing a circuit configuration of a main part in the bidirectional DC-DC converter device according to the second embodiment of the present invention.

With reference to FIG. 5, the bidirectional DC-DC converter device here also shows the circuit of the bidirectional DC-DC converter portion which is a schematic diagram of the control unit 6 shown in FIG. In the case of the bidirectional DC-DC converter device according to the second embodiment, the DC link switch 50 is a first diode D1 inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply (HV) 1 and parallel to the first diode D1. The high-voltage side first switching element H0-1 connected, the second diode D2 inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply (HV) 1, and the high-voltage side second diode connected in parallel to the second diode D2. In addition to having a two-parallel configuration for thermal dispersion including the switching element H0-2 of 2, in the second switching circuit 4', the lead wire from the smoothing diode L and the smoothing capacitor Cc are connected in parallel. The configuration includes the low-voltage side first switching element S0-1 and the low-voltage side second switching element S0-2. Further, the control unit 6 turns off the first switching element H0-1 on the high voltage side of the DC link switch 50 and turns on the second switching element H0-2 on the high voltage side for a predetermined time at the time of boosting the discharge operation. One pair of switching elements H1 and H4 arranged diagonally of each switching element H1 to H4 in the first switching circuit 3 is turned on, and the other pair of switching elements H2 and H3 arranged diagonally are turned on. Turn off and the backflow current from the resonance choke coil Lr toward the second switching element H0-2 on the high voltage side of the DC link switch 50 via the primary winding of the insulating transformer T and the high voltage side DC power supply (HL) 1. The first switching element S0-1 on the low voltage side and the second switching element S0-2 on the low voltage side in the second switching circuit 4'are turned off, and the switching elements S1 to S4 are arranged diagonally. Generation of backflow current in the first switching circuit 3 during rectification processing with one pair of switching elements S1 and S4 turned on and the other pair of switching elements S2 and S4 arranged diagonally turned on. Control is performed to reduce the switching loss by causing a weak current flowing in the direction opposite to the direction in which the current flows to cause cancellation. Specifically, it has the effect of reducing the total switching loss of the switching elements S1 to S4 in the second switching circuit 4'. The control function by the control unit 6 can be regarded as being executed in the loss reduction control processing step in the control method of the bidirectional DC-DC converter device. Incidentally, the backflow current in the first switching circuit 3 is the timing at which the control unit 6 turns off the first switching element H0-1 on the high voltage side and the second switching element H0-2 on the high voltage side of the DC link switch 50. It can be controlled by having.

Further, the control unit 6 turns off the first switching element H0-1 on the high voltage side of the DC link switch 50 and turns on the second switching element H0-2 on the high voltage side for a predetermined time at the time of boosting the discharge operation. One pair of switching elements H1 and H4 arranged diagonally of each switching element H1 to H4 in the first switching circuit 3 is turned on, and the other pair of switching elements H2 and H3 arranged diagonally are turned on. Keeping it off, a current is passed in the direction toward the high-voltage side DC power supply (HV) 1 via the primary winding of the insulating transformer T and the resonant choke coil Lr to perform rectification processing, and the second switching circuit 4 The first switching element S0-1 on the low voltage side connected to the smoothing capacitor Cc in ′ is kept off, the second switching element S0-2 on the low voltage side is turned on, and the switching elements S1 to S4 are diagonally oriented. Keeping one pair of arranged switching elements S1 and S4 on and the other pair of diagonally arranged switching elements S2 and S3 off to draw the secondary winding of the isolated transformer T from the smoothing inductor L. Control is performed to improve the conversion efficiency by performing rectification processing by passing a current in the direction toward the low-voltage side DC power supply (LV) 2 via the transformer. Specifically, the conversion efficiency in the first switching circuit 3 is improved by allowing a current to flow through the second switching element H0-2 on the high voltage side, which has a smaller loss than the second diode D2 in the DC link switch 50. Can be done. The control function by the control unit 6 can be regarded as being executed in the conversion efficiency improvement control processing step in the control method of the bidirectional DC-DC converter device.

FIG. 6-1 shows the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to each switching element during boosting of the discharge operation of the bidirectional DC-DC converter device according to the second embodiment. It is a timing chart which shows the waveform of the switching operation control signal with respect to S4, and the waveform of the voltage of each switching element H0-1, H0-2, H1 to H4, S0-1, S0-2, S1 to S4. Similarly, FIG. 6-2 shows the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to S4 at the time of boosting the discharge operation of this bidirectional DC-DC converter device. Timing chart showing the current waveform and the current and voltage (specifically, the current of the smoothing inductor L, the voltage of the insulating transformer T, the current and voltage of the resonant choke coil Lr) in each device (FIG. 6- on the time series). 1). Further, FIGS. 7-1 to 7-6 are diagrams showing the current flow in the circuit configuration of the main part of the bidirectional DC-DC converter device during the periods t1 to t6 shown in FIG. 6-1.

With reference to FIGS. 6-1 and 6-2, the waveforms of the switching operation control signals for the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to S4 are initially set. The first switching element H0-1 on the high voltage side of the DC link switch 50 is turned off while the switching elements S1 and S4 in the second switching circuit 4'are kept on, and the second switching on the high voltage side is performed within that period. The on / off timing is set for half the period of the above-mentioned predetermined cycle corresponding to the period (t1 + t2 + t3 + t4 + t5 + t6) from when the element H0-2 is turned on for a predetermined time to when the switching elements S1 and S4 are turned off. It is shown to control as shown in the figure.

Specifically, in the period t1, referring to FIG. 7-1, both the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2 of the DC link switch 50 are turned off. In the first switching circuit 3, the switching elements H1 and H4 are kept off, the switching elements H2 and H3 are kept on, and the current flowing through the resonance choke coil Lr causes a current to flow in the primary winding of the insulating transformer T. The current flows by branching from the resonance choke coil Lr to the flow returning to the resonance choke coil Lr toward the switching elements H1 and H3 and the flow returning to the resonance choke coil Lr toward the switching elements H2 and H4, but on the high pressure side. It is not supplied to the DC power supply (HV) 1. At this time, the resonant choke coil Lr is kept substantially constant. Further, in the second switching circuit 4', the low-voltage side first switching element S0-1 and the low-voltage side second switching element S0-2 are both kept off, and the switching elements S1 to S4 are all on. It is the timing to store energy in the smoothing inductor L. In the second switching circuit 4', the path circulating from the smoothing inductor L to the low-voltage side DC power supply (LV) 2 via the switching element S1 and the switching element S2, and the smoothing inductor L to the switching element S3 and the switching element S4 The low-voltage side DC power supply (LV) that circulates toward the low-voltage side DC power supply (LV) 2 via the circuit and branches from the switching element S1 and passes through the switching element S4 via the secondary winding of the insulating transformer T. ) Current flows along the path that circulates toward 2. The same applies to the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to S4, but the body diode is omitted.

In the period t2, referring to FIG. 7-2, both the high-pressure side first switching element H0-1 and the high-pressure side second switching element H0-2 of the DC link switch 50 are kept off, and the first one. In the switching circuit 3, the switching elements H1 and H4 are turned off, the switching elements H2 and H3 are also turned off, and the switching elements H1 to H4 are all turned off, but the current is opposite to the case of the period t1 via the body diode. Flows, branches from the resonance choke coil Lr through the switching element H1, passes through the high-pressure side first switching element H0-1, the high-pressure side second switching element H0-2, and the high-pressure side DC power supply (HV) 1. A current flows through a path that circulates from the switching element H4 toward the primary winding of the insulating transformer T. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side, the second switching element S0-2 on the low voltage side, and the switching elements S1 and S4 are kept on, and the switching elements S2 and S3 are moved. It is time to turn it off and release the energy stored in the smoothing inductor L, but a current flows into the smoothing capacitor Cc via the body diode. In the second switching circuit 4', the path is circulated from the smoothing inductor L through the switching element S1 to the secondary winding of the insulating transformer T and the switching element S4 toward the low voltage side DC power supply (LV) 2. A path that circulates from the smoothing inductor L through the low-voltage side first switching element S0-1 and the low-voltage side second switching element S0-2, through the smoothing capacitor Cc, and toward the low-voltage side DC power supply (LV) 2. Current flows at. Incidentally, in the period t2, the voltage of the second switching element S0-2 on the low voltage side becomes 0V.

In the period t3, referring to FIG. 7-3, the first switching element H0-1 on the high pressure side of the DC link switch 50 is switched off, the second switching element H0-2 on the high pressure side is switched on, and the first In the switching circuit 3, the switching elements H1 and H4 are switched on, the switching elements H2 and H3 are kept off, and the resonance choke coil Lr passes through the switching element H1 to the second switching element H0-2 on the high pressure side and the high pressure. A current flows through a path that circulates from the switching element H4 to the primary winding of the insulated transformer T via the side DC power supply (HV) 1. Since the current at this time flows not to the body diode of the second switching element H0-2 on the high voltage side of the DC link switch 50 but to the second switching element H0-2 itself on the high voltage side, the conversion efficiency improvement control process is performed. It will be. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side is turned off, the second switching element S0-2 on the low voltage side is switched on, and the switching elements S1 and S4 are kept on. The switching elements S2 and S3 are kept off. When the second switching element S0-2 on the low voltage side is turned on by soft switching, all the current flowing through the body diodes of the first switching element S0-1 on the low voltage side and the second switching element S0-2 on the low voltage side is low voltage. The current that flows into the second switching element S0-2 on the side and flows through the smoothing capacitor Cc decreases with a predetermined inclination to 0, and the current that flows into the second switching element S0-2 on the low voltage side reverses and switches. Assists the current of element S1. As a result, in the second switching circuit 4', the path that circulates from the smoothing inductor L through the switching element S1 to the secondary winding of the insulating transformer T and the switching element S4 toward the low voltage side DC power supply (LV) 2. A current flows through the smoothing inductor L, the second switching element S0-2 on the low voltage side, the smoothing capacitor Cc, and the path circulating toward the low voltage side DC power supply (LV) 2. Incidentally, in the rectification process in the second switching circuit 4', a current flows in the opposite direction between the smoothing capacitor Cc and the second switching element S0-2 on the low voltage side.

In the period t4, referring to FIG. 7-4, the first switching element H0-1 on the high pressure side of the DC link switch 50 is kept off, the second switching element H0-2 on the high pressure side is kept on, and the first one. In the switching circuit 3, the switching elements H1 and H4 are kept on, the switching elements H2 and H3 are kept off, and the resonance choke coil Lr passes through the switching element H1 to the second high-voltage side as in the case of the period t3. A current flows through a path that circulates from the switching element H4 to the primary winding of the insulating transformer T via the switching element H0-2 and the high-voltage side DC power supply (HV) 1. The current of the resonant choke coil Lr at this time is not suddenly changed. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side is switched off, the second switching element S0-2 on the low voltage side is switched off, and the switching elements S1 and S4 are kept on. The switching elements S2 and S3 are kept off. Here, the current flowing through the smoothing capacitor Cc has no place to go, passes through the body diodes of the switching elements S2 and S3, and eventually becomes 0, and the voltage of the switching elements S2 and S3 also becomes 0. In the second switching circuit 4', the path from the smoothing inductor L through the switching element S1 to the secondary winding of the isolation transformer T through the switching element S3 to the switching element S1 and the secondary winding of the isolation transformer T. A path that circulates from the switching element S4 to the low-voltage side DC power supply (LV) 2 and a path that returns from the secondary winding of the isolation transformer T to the secondary winding of the isolation transformer T through the switching element S4. Current flows.

In the period t5, referring to FIG. 7-5, the high-voltage side first switching element H0-1 of the DC link switch 50 is kept off, the high-voltage side second switching element H0-2 is kept on, and the first In the switching circuit 3, the switching elements H1 and H4 are kept on, the switching elements H2 and H3 are also kept off, and the high-voltage side DC power supply (HV) 1 to the high-voltage side second switching element H0-2 and the switching element H1 are kept on. A path that circulates through the switching element H3 and a branch from the switching element H1 through the switching element H4 via the primary winding of the resonance choke coil Lr and the insulating transformer T, and via the switching element H2. A backflow current flows in a path that circulates back to the resonant choke coil Lr and a path that circulates from the switching element H4 toward the high-voltage side DC power supply (HV) 1. Further, in the second switching circuit 4', in response to the voltage of the switching elements S2 and S3 becoming 0, the switching elements S2 and S3 are turned on and the current passing through the switching elements S1 and S4 before that is turned on. It is also passed through the switching elements S2 and S3. Since the switching operation at this time is performed by zero volt switching (ZVS), no switching loss occurs. As a result, in the second switching circuit 4', the path traveling from the smoothing inductor L through the switching element S1 and the switching element S2 toward the low-voltage side DC power supply (LV) 2 and the smoothing inductor L through the switching element S3 and the switching element A current flows through a path that circulates toward the low-voltage side DC power supply (LV) 2 through S4. At this time, in the second switching circuit 4', since the current of the resonance choke coil Lr is opposite in the first switching circuit 3, energy is sent through the isolation transformer T and passes through the switching elements S1 and S4. Then, a weak current tries to flow in the direction opposite to the current flowing in the isolation transformer T (secondary winding) and cancels each other out, so that a loss reduction control process for reducing the switching loss is performed.

In the period t6, referring to FIG. 7-6, the high-voltage side first switching element H0-1 of the DC link switch 50 is kept off, and the high-voltage side second switching element H0-2 is switched off. In the first switching circuit 3, the switching elements H1 and H4 are kept on, the switching elements H2 and H3 are kept off, and the current flows in the opposite direction to the case of the period t1, but the high voltage side DC power supply (HV) 1 has a current. Not supplied. Further, in the second switching circuit 4', although the switch setting is maintained, the backflow current does not flow, so that the smoothing inductor L passes through the switching element S1 and the switching element S2 to the low voltage side DC power supply (LV) 2. The path that circulates toward and the smoothing inductor L is branched through the switching element S3 and the switching element S3 and the path that circulates toward the low-voltage side DC power supply (LV) 2 and is branched through the switching element S3. A current flows from the winding path through the switching element S2 to the low-voltage side DC power supply (LV) 2.

In the other half of the predetermined cycle after the period t6, the first switching element H0-1 on the high voltage side of the DC link switch 50 is switched on and then turned off again, and the second switching element H0-2 on the high voltage side is switched on. Keep off and then switch it on again. At this time, in the first switching circuit 3, the switching elements H1 and H4 are kept off and then switched on again, and the switching elements H2 and H3 are switched on and maintained and then switched off again. Further, in the second switching circuit 4', the low-voltage side first switching element S0-1 connected to the smoothing capacitor Cc is switched on and then turned off again to switch the low-voltage side second switching element S0-2. Keep it off and then switch it on again. Further, one pair of switching elements S1 and S4 arranged diagonally are kept on, then turned off and then turned on, and the other pair of switching elements S2 and S3 arranged diagonally are turned on. From to off, off to on, on to off.

That is, in the bidirectional DC-DC converter device according to the second embodiment, the control unit 6 turns off the first switching element H0-1 on the high pressure side of the DC link switch 50 at a predetermined cycle when the discharge operation is boosted. After turning on, on to off, and maintaining the high-pressure side second switching element H0-2 from off to on and on to off within the off period of the high-pressure side first switching element H0-1, the high-pressure side first While repeating the operation of turning on the switching element H0-1 within the off period, one pair of switching elements H1 and H4 arranged diagonally of the switching elements H1 to H4 in the first switching circuit 3 is turned off. From on, on to off, from off to on, the other pair of switching elements H2, H3 arranged diagonally are repeated from on to off, off to on, from on to off, and then the second The first switching element S0-1 on the low pressure side of each switching element S0-1, S0-2, S1 to S4 in the switching circuit 4'of the above is kept off, then turned on, turned on to off, and the second on the low pressure side. The operation of turning the switching element S0-2 from off to on and from on to off within the off period of the first switching element S0-1 on the high pressure side is repeated, and one pair of switching elements S1 arranged diagonally. By keeping S4 on, then turning it off and then on, and repeating the operation of turning the other pair of switching elements S2 and S3 arranged diagonally from on to off, off to on, and on to off. The loss reduction control process and the conversion efficiency improvement control process described above can be included in the rectification process as in the case of the first embodiment. As a result, the smoothing inductor L current and the resonance choke coil Lr current shown in FIG. 6-2 are the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2 of the conventional DC link switch 50. It is suppressed to a small value as compared with the case of boosting the discharge operation performed while it is turned off. Further, also here, if the control timing of the switching operation control signal is appropriately changed, the conversion efficiency can always be in the optimum state (a state close to the maximum efficiency).

FIG. 8-1 shows the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to each switching element at the time of boosting the discharge operation of the bidirectional DC-DC converter device according to the second embodiment. It is a timing chart which shows the waveform of the switching operation control signal which concerns on the well-known technique for S4, and the waveform of the voltage of each switching element H0-1, H0-2, H1-H4, S0-1, S0-2, S1-S4. Similarly, FIG. 8-2 shows the switching elements H0-1, H0-2, and H1 to each other when the switching operation control signal shown in FIG. 8-1 is applied at the time of boosting the discharge operation of the bidirectional DC-DC converter device. Current waveforms of H4, S0-1, S0-2, S1 to S4 and current and voltage in each device (specifically, current of smoothing inductor L, voltage of isolated transformer T, current and voltage of resonant choke coil Lr) It is a timing chart which shows the waveform of. Further, FIGS. 9-1 to 9-5 are diagrams showing the current flow in the circuit configuration of the main part of the bidirectional DC-DC converter device during the periods t1 to t5 shown in FIG. 8-1.

With reference to FIGS. 8-1 and 8-2, the waveforms of the switching operation control signals for the switching elements H0-1, H0-2, H1 to H4, S0-1, S0-2, and S1 to S4 are initially set. The first switching element H0-1 on the high-voltage side and the second switching element H0-2 on the high-voltage side of the DC link switch 50 are turned off while the switching elements S1 and S4 in the second switching circuit 4'are kept on. It is shown that the on / off timing is controlled as shown in the figure in a half period of the above-mentioned predetermined cycle corresponding to the period (t1 + t2 + t3 + t4 + t5) until immediately before the switching elements S1 and S4 are turned off. ..

Specifically, in the period t1, referring to FIG. 9-1, both the high-pressure side first switching element H0-1 and the high-pressure side second switching element H0-2 of the DC link switch 50 are turned off. In the first switching circuit 3, the switching elements H1 and H4 are kept off, the switching elements H2 and H3 are kept on, and the current flowing through the resonant choke coil Lr causes a current in the primary winding of the insulating transformer T. Flows and branches from the resonance choke coil Lr through the primary winding of the insulating transformer T via the switching element H3, and the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2. A current flows in a cyclic path returning to the resonance choke coil Lr toward the high-voltage side DC power supply (HV) 1 and the switching element H2 through the body diode of the above. Further, in the second switching circuit 4', the low-voltage side first switching element S0-1 and the low-voltage side second switching element S0-2 are both kept off, and the switching elements S1 to S4 are all on. It is the timing to store energy in the smoothing inductor L. In the second switching circuit 4', the path that circulates from the smoothing inductor L through the switching element S1 and the switching element S2 toward the low-voltage side DC power supply (LV) 2, and the smoothing inductor L connects the switching element S3 and the switching element S4. A path that circulates toward the low-voltage side DC power supply (LV) 2 through the circuit, branches from the switching element S3, passes through the secondary winding of the isolation transformer T, passes through the switching element S2, and passes through the low-voltage side DC power supply (LV) 2. A current flows in a path that circulates toward. Incidentally, in the first switching circuit 3, the current flowing through the resonant choke coil Lr gradually decreases and eventually becomes zero.

In the period t2, referring to FIG. 9-2, both the high-pressure side first switching element H0-1 and the high-pressure side second switching element H0-2 of the DC link switch 50 are kept off, and the first one. In the switching circuit 3, the switching elements H1 and H4 are turned off, the switching elements H2 and H3 are also turned off, and the switching elements H1 to H4 are all turned off, but the current is opposite to the case of the period t1 via the body diode. Flows and branches from the resonance choke coil Lr through the switching element H1, the body diode of the first switching element H0-1 on the high pressure side and the second switching element H0-2 on the high pressure side, and the high pressure side DC power supply (HV) 1. A current flows in a path that circulates from the switching element H4 to the primary winding of the insulating transformer T via the above. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side and the second switching element S0-2 on the low voltage side are kept off, the switching elements S1 and S4 are kept on, and switching is performed. It is time to turn off the elements S2 and S3 to release the energy stored in the smoothing inductor L, but a current flows into the smoothing capacitor Cc via the body diode. In the second switching circuit 4', the path is circulated from the smoothing inductor L through the switching element S1 to the secondary winding of the insulating transformer T and the switching element S4 toward the low voltage side DC power supply (LV) 2. A path that circulates from the smoothing inductor L to the low-voltage side DC power supply (LV) 2 through the body diode of the low-voltage side first switching element S0-1 and the low-voltage side second switching element S0-2 and the smoothing capacitor Cc. Current flows with. Incidentally, in the period t2, the voltage of the second switching element S0-2 on the low voltage side becomes 0V.

In the period t3, referring to FIG. 9-3, both the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2 of the DC link switch 50 are kept off, and the first one. In the switching circuit 3, the switching elements H1 and H4 are switched on, the switching elements H2 and H3 are kept off, and the resonance choke coil Lr branches through the switching element H1 as in the case of the period t2, and the high voltage side. A path that circulates from the switching element H4 to the primary winding of the insulated transformer T via the first switching element H0-1, the second switching element H0-2 on the high voltage side, and the DC power supply (HV) 1 on the high voltage side. Current flows at. Since the current at this time flows through the body diodes of the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2 in the DC link switch 50, the conversion efficiency is lowered. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side is turned off, the second switching element S0-2 on the low voltage side is switched on, and the switching elements S1 and S4 are kept on. The switching elements S2 and S3 are kept off. When the second switching element S0-2 on the low voltage side is turned on by soft switching, all the current flowing through the body diodes of the first switching element S0-1 on the low voltage side and the second switching element S0-2 on the low voltage side is low voltage. The current that flows into the second switching element S0-2 on the side and flows through the smoothing capacitor Cc decreases with a predetermined inclination to 0, and the current that flows into the second switching element S0-2 on the low voltage side reverses and switches. Assists the current of element S1. In the second switching circuit 4', a path and a smoothing inductor that circulate from the smoothing inductor L through the switching element S1 to the secondary winding of the insulating transformer T and the switching element S4 toward the low-voltage side DC power supply (LV) 2. A current flows from L through the second switching element S0-2 on the low voltage side, through the smoothing capacitor Cc, and on the path that circulates toward the DC power supply (LV) 2 on the low voltage side. Incidentally, in the rectification process in the second switching circuit 4', a current flows in the opposite direction between the smoothing capacitor Cc and the second switching element S0-2 on the low voltage side.

In the period t4, referring to FIG. 9-4, both the high-pressure side first switching element H0-1 and the high-pressure side second switching element H0-2 of the DC link switch 50 are kept off, and the first one. In the switching circuit 3, the switching elements H1 and H4 are kept on, the switching elements H2 and H3 are kept off, and the switching element H1 is transferred from the resonance choke coil Lr as in the case of the period t2 as in the case of the period t2. The primary winding of the isolated transformer T from the switching element H4 via the high-pressure side first switching element H0-1, the high-pressure side second switching element H0-2, and the high-pressure side DC power supply (HV) 1. Current flows along a path that circulates toward the line. The current of the resonant choke coil Lr at this time is not suddenly changed. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side is switched off, the second switching element S0-2 on the low voltage side is switched off, and the switching elements S1 and S4 are kept on. The switching elements S2 and S3 are kept off. Here, the current flowing through the smoothing capacitor Cc has no place to go, passes through the body diodes of the switching elements S2 and S3, and eventually becomes 0, and the voltage of the switching elements S2 and S3 also becomes 0. In the second switching circuit 4', the current circulates from the smoothing inductor L through the switching element S1 from the secondary winding of the isolation transformer T to the low voltage side DC power supply (LV) 2 via the switching element S4. Flows.

In the period t5, referring to FIG. 9-5, both the high-pressure side first switching element H0-1 and the high-pressure side second switching element H0-2 of the DC link switch 50 are kept off, and the first one. In the switching circuit 3, the switching elements H1 and H4 are kept on, the switching elements H2 and H3 are kept off, and the switching element H1 is transferred from the resonance choke coil Lr as in the case of the period t2 as in the case of the period t2. The primary winding of the isolated transformer T from the switching element H4 via the high-pressure side first switching element H0-1, the high-pressure side second switching element H0-2, and the high-pressure side DC power supply (HV) 1. Current flows along a path that circulates toward the line. Further, in the second switching circuit 4', the first switching element S0-1 on the low voltage side and the second switching element S0-2 on the low voltage side are kept off, the switching elements S1 and S4 are kept on, and switching is performed. The elements S2 and S3 are switched on. In the second switching circuit 4', in response to the voltage of the switching elements S2 and S3 becoming 0, the switching elements S2 and S3 are turned on and the current passing through the switching elements S1 and S4 before that is turned on. Make sure that it also passes through S2 and S3. Since the switching operation at this time is performed by zero volt switching (ZVS), no switching loss occurs. As a result, in the second switching circuit 4', the path traveling from the smoothing inductor L through the switching element S1 and the switching element S2 toward the low-voltage side DC power supply (LV) 2 and the smoothing inductor L through the switching element S3 and the switching element A low-voltage side DC power supply (a path that circulates through S4 toward the low-voltage side DC power supply (LV) 2 and a smoothing inductor L through the switching element S1 and the secondary winding of the insulating transformer T and the switching element S4. A current flows along the path that circulates toward LV) 2.

During the other half of the predetermined period after the period t5, the high-voltage side first switching element H0-1 and the high-voltage side second switching element H0-2 of the DC link switch 50 are kept off. At this time, in the first switching circuit 3, the switching elements H1 and H4 are switched from on to off and maintained, and then switched on again, and the switching elements H2 and H3 are switched from off to on and maintained, and then turned off again. Switch to. Further, in the second switching circuit 4', the low-voltage side first switching element S0-1 connected to the smoothing capacitor Cc is switched on and then turned off again to switch the low-voltage side second switching element S0-2. Keep it off and then switch it on again. Further, one pair of switching elements S1 and S4 arranged diagonally are kept on, then turned off and then turned on, and the other pair of switching elements S2 and S3 arranged diagonally are turned on. From to off, off to on, on to off.

That is, in the bidirectional DC-DC converter device to which the switching operation control signal of the well-known technique is applied, the control unit 6 controls the first switching element H0 on the high pressure side of the DC link switch 50 at a predetermined cycle when the discharge operation is boosted. -1, The second switching element H0-2 on the high pressure side is kept off of the first switching element H0-1 on the high pressure side, and the second switching elements H0-2 on the high pressure side are arranged diagonally to each of the switching elements H1 to H4 in the first switching circuit 3. One pair of switching elements H1 and H4 are turned from off to on, on to off, off to on, and the other pair of switching elements H2 and H3 arranged diagonally are turned from on to off, off to on and on. After repeating the operation of turning off from, and further keeping the first switching element S0-1 on the low pressure side of each switching element S0-1, S0-2, S1 to S4 in the second switching circuit 4'off. The operation of turning the second switching element S0-2 on the low pressure side from on to off and turning the second switching element S0-2 on the low pressure side from off to on and from on to off within the off period of the first switching element S0-1 on the high pressure side is repeated and diagonally. One pair of switching elements S1 and S4 arranged in the above are kept on, then turned off and then turned on, and the other pair of switching elements S2 and S3 arranged diagonally from on to off and off. The rectification process is performed by repeating the operation of turning on and on to off. As a result, the smoothing inductor L current and the resonant choke coil Lr current shown in FIG. 8-2 are larger than those in the second embodiment shown in FIG. 6-2. In such a state, even if the control timing of the switching operation control signal is appropriately changed, it is impossible to always obtain the optimum conversion efficiency (a state close to the maximum efficiency).

In each of the above-described embodiments, the DC link switches 5 and 50 connected to the high-voltage side DC power supply (HV) 1 in the bidirectional DC-DC converter device have been described as separate circuits from the first switching circuit 3. In terms of functional configuration, it may be considered to be included in the first switching circuit 3.

1 High-voltage side DC power supply (HV)
2 Low voltage side DC power supply (LV)
3, 4, 4'Switching circuit 5, 50 DC link switch 6 Control unit 6a Discharge operation switching unit 6b Charging operation switching unit 6c Pulse width modulation (PWM) unit Cc Smoothing capacitor D diode (fast recovery diode)
L Smoothing Inductor Lr Resonant Choke Coil H0, H0-1, H0-2, H1 to H4, S0, S0-1, S0-2, S1 to S4 Switching Element T Isolation Transformer

Claims (12)

A first switching circuit that performs rectification processing according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply.
It is interposed between the high-voltage side DC power supply and the DC terminal of the first switching circuit, and is connected in parallel to the diode and the diode inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply. A DC link switch consisting of a switching element and
A second switching circuit that performs rectification processing according to the switching operation of multiple switching elements with body diodes including smoothing capacitors connected in parallel with a smoothing inductor interposed in the low-voltage side DC power supply.
Insulation that magnetically couples the primary winding connected by interposing a resonance choke coil between the AC terminals of the first switching circuit and the secondary winding connected between the AC terminals of the second switching circuit. With a transformer
A bidirectional DC-DC converter device including a control unit that controls the switching operation in the first switching circuit and the second switching circuit, and also controls on / off of the switching element of the DC link switch. In
The DC link switch includes a high-voltage side zeroth switching element as the switching element.
The first switching circuit is diagonal to the high-pressure side first switching element and the high-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A high-pressure side second switching element and a high-pressure side third switching element, which are the other pair of switching elements arranged in the direction, are provided.
The second switching circuit is diagonal to the low-pressure side first switching element and the low-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A low-voltage side second switching element and a low-voltage side third switching element, which are the other pair of switching elements arranged in the direction, and a low-voltage side zero-th switching element connected to the smoothing capacitor are provided.
At the time of boosting, the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply.
The high voltage side first switching element, the high voltage side fourth switching element, and the low voltage side zero switching element are off, and the high voltage side second switching element, the high voltage side third switching element, and the low voltage side first. From the state where the switching element, the low voltage side second switching element, the low voltage side third switching element, and the low voltage side fourth switching element are on.
The voltage of the low voltage side zero switching element became 0V, and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side third switching element were switched off. rear,
A bidirectional DC-DC converter device characterized in that the high-voltage side zero-th switching element is switched on at the first timing for switching the high-voltage side first switching element and the high-voltage side fourth switching element on. In the bidirectional DC-DC converter device according to claim 1,
When the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply, the control unit further
After the first timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, and the low voltage side. From the state where the fourth switching element is on, the high voltage side second switching element, the high voltage side third switching element, and the low voltage side zero switching element are off.
After switching off the high-voltage side first switching element, the high-voltage side fourth switching element, the low-voltage side first switching element, and the low-voltage side fourth switching element,
Bidirectionally characterized in that the high-voltage side zero switching element and the low-voltage side zero switching element are switched on at the second timing of switching the high-voltage side second switching element and the high-voltage side third switching element on. DC-DC converter device. In the bidirectional DC-DC converter device according to claim 2.
When the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply, the control unit further
After the first timing Before the second timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, and the low voltage side fourth switching element are on, and the high voltage side first. (Ii) From a state in which the switching element, the high voltage side third switching element, the low voltage side zero switching element, the low voltage side second switching element, and the low voltage side third switching element are off.
In response to the voltage of the low voltage side second switching element and the low voltage side third switching element becoming 0V, after switching on the low voltage side second switching element and the low voltage side third switching element, the high voltage A bidirectional DC-DC converter device characterized by switching the side zeroth switching element off. A first switching circuit that performs rectification processing according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply.
A DC link switch interposed between the high-voltage side DC power supply and the DC terminal of the first switching circuit,
A second switching circuit that performs rectification processing according to the switching operation of multiple switching elements with body diodes including smoothing capacitors connected in parallel with a smoothing inductor interposed in the low-voltage side DC power supply.
Insulation that magnetically couples the primary winding connected by interposing a resonance choke coil between the AC terminals of the first switching circuit and the secondary winding connected between the AC terminals of the second switching circuit. With a transformer
A bidirectional DC-DC converter device including a control unit that controls the switching operation in the first switching circuit and the second switching circuit, and also controls on / off of the switching element of the DC link switch. In
The DC link switch includes a first diode inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply, a high-voltage side first zero switching element connected in parallel to the first diode, and a high-voltage cathode. A second diode inserted in series so as to face the positive electrode of the side DC power supply and a high-voltage side second zero switching element connected in parallel to the second diode are provided.
The first switching circuit is diagonal to the high-pressure side first switching element and the high-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A high-pressure side second switching element and a high-pressure side third switching element, which are the other pair of switching elements arranged in the direction, are provided.
The second switching circuit is diagonal to a low-pressure side first switching element and a low-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. The other pair of switching elements arranged in the direction, the low pressure side second switching element and the low pressure side third switching element, and the low pressure side first zero switching element and the low pressure side second connected in parallel to the smoothing capacitor. Equipped with a zeroth switching element
At the time of boosting, the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply.
The high-voltage side second switching element, the high-voltage side third switching element, the low-voltage side first switching element, the low-voltage side second switching element, the low-voltage side third switching element, and the low-voltage side fourth switching element are turned on. From the state where the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first zero switching element, and the low voltage side second zero switching element are off.
The voltage of the low voltage side second zero switching element becomes 0V, and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side third switching element are turned off. After switching
The feature is that the high-voltage side second zero switching element is switched on at the first timing of switching the high-voltage side first switching element, the high-voltage side fourth switching element, and the low-voltage side second zero switching element on. Bidirectional DC-DC converter device. In the bidirectional DC-DC converter device according to claim 4,
When the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply, the control unit further
After the first timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, the low voltage side first. (Iv) The switching element is on, the high voltage side first zero switching element, the high voltage side second zero switching element, the high voltage side second switching element, the high voltage side third switching element, the low voltage side first zero switching. From the state where the element and the second zero switching element on the low voltage side are off
After switching off the high-voltage side first switching element, the high-voltage side fourth switching element, the low-voltage side first switching element, and the low-voltage side fourth switching element,
The feature is that the high-voltage side first zero switching element is switched on at the second timing at which the high-voltage side second switching element, the high-voltage side third switching element, and the low-voltage side first zero switching element are switched on. Bidirectional DC-DC converter device. In the bidirectional DC-DC converter device according to claim 5,
When the control unit supplies power from the low-voltage side DC power supply to the high-voltage side DC power supply, the control unit further
After the first timing Before the second timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side second zero switching element, the low voltage side first switching element, the low voltage side fourth A state in which the switching element is on, the high voltage side second switching element, the high voltage side third switching element, the low voltage side first zero switching element, the low voltage side second switching element, and the low voltage side third switching element are off. From
In response to the voltage of the low voltage side second switching element and the low voltage side third switching element becoming 0V, after switching the low voltage side second zero switching element off, the low voltage side second switching element and the low voltage side second switching element and A bidirectional DC-DC converter device characterized in that the low-voltage side third switching element is switched on and then the high-voltage side second zero switching element is switched off. A first switching circuit that performs rectification processing according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply.
It is interposed between the high-voltage side DC power supply and the DC terminal of the first switching circuit, and is connected in parallel to the diode and the diode inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply. A DC link switch consisting of a switching element and
A second switching circuit that performs rectification processing according to the switching operation of multiple switching elements with body diodes including smoothing capacitors connected in parallel with a smoothing inductor interposed in the low-voltage side DC power supply.
Insulation that magnetically couples the primary winding connected by interposing a resonance choke coil between the AC terminals of the first switching circuit and the secondary winding connected between the AC terminals of the second switching circuit. With a transformer
A bidirectional DC-DC converter device including a control unit that controls the switching operation in the first switching circuit and the second switching circuit, and also controls on / off of the switching element of the DC link switch. In the control method of
The DC link switch includes a high-voltage side zeroth switching element as the switching element.
The first switching circuit is diagonal to the high-pressure side first switching element and the high-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A high-pressure side second switching element and a high-pressure side third switching element, which are the other pair of switching elements arranged in the direction, are provided.
The second switching circuit is diagonal to the low-pressure side first switching element and the low-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A low-voltage side second switching element and a low-voltage side third switching element, which are the other pair of switching elements arranged in the direction, and a low-voltage side zero-th switching element connected to the smoothing capacitor are provided.
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply,
The high voltage side first switching element, the high voltage side fourth switching element, and the low voltage side zero switching element are off, and the high voltage side second switching element, the high voltage side third switching element, and the low voltage side first. From the state where the switching element, the low voltage side second switching element, the low voltage side third switching element, and the low voltage side fourth switching element are on.
The voltage of the low voltage side zero switching element became 0V, and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side third switching element were switched off. rear,
A bidirectional DC-DC converter device including a step of turning on the high-voltage side zero-th switching element at the first timing of turning on the high-voltage side first switching element and the high-voltage side fourth switching element. Control method. In the control method of the bidirectional DC-DC converter device according to claim 7.
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply, further
After the first timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, and the low voltage side. From the state where the fourth switching element is on, the high voltage side second switching element, the high voltage side third switching element, and the low voltage side zero switching element are off.
After switching off the high-voltage side first switching element, the high-voltage side fourth switching element, the low-voltage side first switching element, and the low-voltage side fourth switching element,
It is characterized by including a step of switching on the high-voltage side zero switching element and the low-voltage side zero switching element at the second timing of switching the high-voltage side second switching element and the high-voltage side third switching element on. A method of controlling a bidirectional DC-DC converter device. The control method for the bidirectional DC-DC converter device according to claim 1, according to claim 8.
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply, further
After the first timing Before the second timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, and the low voltage side fourth switching element are on, and the high voltage side first. (Ii) From a state in which the switching element, the high voltage side third switching element, the low voltage side zero switching element, the low voltage side second switching element, and the low voltage side third switching element are off.
In response to the voltage of the low voltage side second switching element and the low voltage side third switching element becoming 0V, after switching on the low voltage side second switching element and the low voltage side third switching element, the high voltage A control method for a bidirectional DC-DC converter device, comprising the step of switching the side zeroth switching element off. A first switching circuit that performs rectification processing according to the switching operation of a plurality of switching elements with body diodes connected in parallel to the high-voltage side DC power supply.
A DC link switch interposed between the high-voltage side DC power supply and the DC terminal of the first switching circuit,
A second switching circuit that performs rectification processing according to the switching operation of multiple switching elements with body diodes including smoothing capacitors connected in parallel with a smoothing inductor interposed in the low-voltage side DC power supply.
Insulation that magnetically couples the primary winding connected by interposing a resonance choke coil between the AC terminals of the first switching circuit and the secondary winding connected between the AC terminals of the second switching circuit. With a transformer
A bidirectional DC-DC converter device including a control unit that controls the switching operation in the first switching circuit and the second switching circuit, and also controls on / off of the switching element of the DC link switch. In the control method of
The DC link switch includes a first diode inserted in series so that the cathode faces the positive electrode of the high-voltage side DC power supply, a high-voltage side first zero switching element connected in parallel to the first diode, and a high-voltage cathode. A second diode inserted in series so as to face the positive electrode of the side DC power supply and a high-voltage side second zero switching element connected in parallel to the second diode are provided.
The first switching circuit is diagonal to the high-pressure side first switching element and the high-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. A high-pressure side second switching element and a high-pressure side third switching element, which are the other pair of switching elements arranged in the direction, are provided.
The second switching circuit is diagonal to a low-pressure side first switching element and a low-pressure side fourth switching element, which are one pair of switching elements arranged diagonally as the plurality of switching elements with body diodes. The other pair of switching elements arranged in the direction, the low pressure side second switching element and the low pressure side third switching element, and the low pressure side first zero switching element and the low pressure side second connected in parallel to the smoothing capacitor. Equipped with a zeroth switching element
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply,
The high-voltage side second switching element, the high-voltage side third switching element, the low-voltage side first switching element, the low-voltage side second switching element, the low-voltage side third switching element, and the low-voltage side fourth switching element are turned on. From the state where the high voltage side first switching element, the high voltage side fourth switching element , the low voltage side first zero switching element, and the low voltage side second zero switching element are off.
The voltage of the low voltage side second zero switching element becomes 0V, and the high voltage side second switching element, the high voltage side third switching element, the low voltage side second switching element, and the low voltage side third switching element are turned off. After switching
The step includes a step of turning on the high-voltage side second zero switching element at the first timing of switching the high-voltage side first switching element, the high-voltage side fourth switching element, and the low-voltage side second zero switching element on. A control method for a bidirectional DC-DC converter device, characterized in that. In the control method of the bidirectional DC-DC converter device according to claim 10.
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply, further
After the first timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side first switching element, the low voltage side second switching element, the low voltage side third switching element, the low voltage side first. (Iv) The switching element is on, the high voltage side first zero switching element, the high voltage side second zero switching element, the high voltage side second switching element, the high voltage side third switching element, the low voltage side first zero switching. From the state where the element and the second zero switching element on the low voltage side are off
After switching off the high-voltage side first switching element, the high-voltage side fourth switching element, the low-voltage side first switching element, and the low-voltage side fourth switching element,
The step includes a step of turning on the high-voltage side first zero switching element at the second timing of switching the high-voltage side second switching element, the high-voltage side third switching element, and the low-voltage side first zero switching element on. A control method for a bidirectional DC-DC converter device, characterized in that. In the control method of the bidirectional DC-DC converter device according to claim 11,
When the control unit boosts power from the low-voltage side DC power supply to the high-voltage side DC power supply,
After the first timing Before the second timing, the high voltage side first switching element, the high voltage side fourth switching element, the low voltage side second zero switching element, the low voltage side first switching element, the low voltage side fourth A state in which the switching element is on, the high voltage side second switching element, the high voltage side third switching element, the low voltage side first zero switching element, the low voltage side second switching element, and the low voltage side third switching element are off. From
In response to the voltage of the low voltage side second switching element and the low voltage side third switching element becoming 0V, after switching the low voltage side second zero switching element off, the low voltage side second switching element and the low voltage side second switching element and A method for controlling a bidirectional DC-DC converter device, comprising a step of switching the low-voltage side third switching element on and then switching the high-voltage side second zero switching element off.