JP7621883B2 - Power Supplies - Google Patents

Description

The present invention relates to a power supply device.

When configuring a high-voltage charger using a converter, a current resonant converter is often used from the viewpoint of efficiency. For example, a high-voltage charger performs control to vary the output voltage (e.g., from 50V to 1000V) while maintaining the output current constant (e.g., 5A). This control uses switching frequency control. A current resonant converter can lower the output voltage and/or the output current by making the switching frequency higher than the resonant frequency.

Patent document 1 describes a power conversion device that has a first operating mode in which all switching elements of the first to third switching legs are switched, and a second operating mode in which at least one of the first to third switching legs, either the upper or lower switching element, is always on, and the other switching element is always off.

JP 2016-173961 A

Current resonant converters are highly efficient when the switching frequency is close to the resonant frequency. However, as the switching frequency of a current resonant converter becomes higher than the resonant frequency due to output control, the reactive power increases, and the efficiency decreases.

The present invention aims to provide a power supply device that can suppress a decrease in efficiency.

A power supply device according to one aspect of the present invention comprises:
A plurality of current resonant converters;
a rectifier circuit including a plurality of rectifier arms each including one of a rectifier element and a switching element on a high side and the other of a rectifier element and a switching element on a low side, and rectifying output voltages of the plurality of current resonant converters and outputting the rectified output voltages to a load;
A control circuit for controlling the plurality of current resonant converters;
a plurality of current sensors each detecting a current flowing through the plurality of rectifier arms;
a plurality of drive circuits each outputting a drive signal for operating the switching element of each of the rectifier arms based on an integral value obtained by integrating an output signal of each of the current sensors;
a reset pulse output circuit that outputs a reset pulse for resetting an integral value of the plurality of driving circuits;
Equipped with
One output terminal of each of the plurality of current resonant converters is electrically connected to the other output terminal of each adjacent current resonant converter and is also electrically connected to one rectifier arm of the plurality of rectifier arms;
The control circuit includes:
A current resonant converter at one end or the other end of the plurality of current resonant converters is always operated, and each of the remaining current resonant converters of the plurality of current resonant converters is controlled to any one of a positive polarity output operation, a negative polarity output operation, and a pause;
The reset pulse output circuit includes:
outputting the reset pulse based on a voltage between the rectifier element and the switching element of a rectifier arm at one end or the other end of the plurality of rectifier arms;
It is characterized by:

In the power supply device,
The reset pulse output circuit includes:
outputting the reset pulse based on a voltage between the rectifier element on a high side or a low side of a rectifier arm at one end or the other end of the plurality of rectifier arms and the switching element on a low side or a high side;
It is characterized by:

In the power supply device,
The current sensor is a Rogowski coil.
It is characterized by:

In the power supply device,
The control circuit includes:
performing control to increase an output voltage to the load from a predetermined first voltage to a predetermined second voltage while maintaining an output current to the load at a predetermined first current;
It is characterized by:

In the power supply device,
The control circuit includes:
After the output voltage reaches the second voltage, a control is performed to reduce the output current from the first current while maintaining the output voltage at the second voltage.
It is characterized by:

In the power supply device,
the number of the current resonant converters is an even number;
It is characterized by:

In the power supply device,
the number of the current resonant converters is an odd number;
It is characterized by:

The power supply device of one aspect of the present invention has the effect of suppressing a decrease in efficiency.

FIG. 1 is a diagram showing a circuit configuration of a power supply device of a comparative example. FIG. 2 is a diagram showing the relationship between the output current and the output voltage of the power supply device of the comparative example. FIG. 3 is a diagram showing time domain waveforms of a drain-source voltage 141 and a current 142 of the transistor Tr1-1 when the output voltage Vout of the power supply device 100 is 800V and the output current Iout is 6.25A. FIG. 4 is a diagram showing time domain waveforms of a drain-source voltage 151 and a current 152 of the transistor Tr1-1 when the output voltage Vout of the power supply device 100 is 50V and the output current Iout is 10A. FIG. 5 is a diagram showing a circuit configuration of the power supply device according to the first embodiment. FIG. 6 is a diagram showing the direction of voltage (current) on the secondary winding side of the power supply device according to the first embodiment. FIG. 7 is a diagram showing the direction of voltage (current) on the secondary winding side of the power supply device according to the first embodiment. FIG. 8 is a diagram showing the relationship between the output current and the output voltage of the power supply device according to the first embodiment. FIG. 9 is a diagram showing time domain waveforms of a voltage 201 and a current 202 between the drain and source of transistors Tr1 from full bridge circuit FB1 to full bridge circuit FB4 when the output voltage Vout of the power supply device 1 is 1000 V and the output current Iout is 5 A. FIG. 10 is a diagram showing time domain waveforms of a voltage 211 and a current 212 between the drain and source of transistors Tr1 from full bridge circuit FB1 to full bridge circuit FB4 when the output voltage Vout of the power supply device 1 is 50 V and the output current Iout is 10 A. FIG. 11 is a diagram showing a circuit configuration of a power supply device according to the second embodiment. FIG. 12 is a diagram showing the relationship between the output current and the output voltage of the power supply device according to the second embodiment. FIG. 13 is a diagram showing a circuit configuration of a power supply device according to the third embodiment. FIG. 14 is a diagram showing a circuit configuration of a drive circuit of a power supply device according to the third embodiment. FIG. 15 is a diagram showing an operation pattern of the power supply device according to the third embodiment, in which the current resonant converter at one end is always operated, and a rectifier arm in which a current flows between the capacitor. FIG. 16 is a diagram showing an operation pattern of the power supply device according to the third embodiment, which always operates the current resonant converter at one end, and the voltage of the rectifier arm. FIG. 17 is a diagram showing an operation pattern in which the current resonant converter at one end of the power supply device according to the third embodiment is always operated, and the voltage of the rectifier arm.

Below, an embodiment of the power supply device of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment.

First embodiment and comparative example
The first embodiment will be described below, but in order to facilitate understanding of the first embodiment, a comparative example will be described first.

Comparative Example
1 is a diagram showing the circuit configuration of a power supply device of a comparative example. The power supply device 100 receives a DC voltage Vin that is output from a DC power supply 121 and smoothed by a capacitor 122, and outputs an output voltage Vout to a load 123.

The power supply device 100 includes a current resonant converter 101, a rectifier circuit 102, a capacitor 103, a voltage sensor 104, a current sensor 105, and a control unit 106.

The current resonant converter 101 is a current resonant converter (LLC converter) that uses LLC resonance. The current resonant converter 101 includes a full bridge circuit FB and a transformer T. A capacitor 115 and an inductance 114 are provided between the full bridge circuit FB and the transformer T. The inductance 114 may be included in the transformer T.

The full bridge circuit FB includes arms 90-1 and 90-2. Arm 90-1 includes a high-side transistor Tr1-1 and a low-side transistor Tr2-1. Arm 90-2 includes a high-side transistor Tr1-2 and a low-side transistor Tr2-2.

In this disclosure, each transistor is described as a MOSFET, but is not limited to this. Each transistor may be a silicon power device, a GaN power device, a SiC power device, an IGBT (Insulated Gate Bipolar Transistor), etc.

Each transistor has a parasitic diode (body diode). A parasitic diode is a pn junction between the back gate and the source and drain of a MOSFET. The parasitic diode can be used as a freewheeling diode to release the transient back electromotive force when the transistor is turned off. In addition to the parasitic diode, a diode element may be added between the drain and source of each transistor.

The source of transistor Tr1-1 is electrically connected to the drain of transistor Tr2-1. The source of transistor Tr1-2 is electrically connected to the drain of transistor Tr2-2.

The drain of transistor Tr1-1 and the drain of transistor Tr1-2 are electrically connected to one end (high potential end) of capacitor 122. The source of transistor Tr2-1 and the source of transistor Tr2-2 are electrically connected to the other end (low potential end) of capacitor 122.

The connection point between the drain of transistor Tr1-1 and the drain of transistor Tr1-2 is one input terminal of the full bridge circuit FB. The connection point between the source of transistor Tr2-1 and the source of transistor Tr2-2 is the other input terminal of the full bridge circuit FB.

A DC voltage Vin is input to the two input terminals of the full bridge circuit FB.

The connection point between the source of transistor Tr1-1 and the drain of transistor Tr2-1 is one output terminal of the full bridge circuit FB. The connection point between the source of transistor Tr1-2 and the drain of transistor Tr2-2 is the other output terminal of the full bridge circuit FB.

The transformer T includes a primary winding 110, a secondary winding 111, and a core 112. The primary winding 110 and the secondary winding 111 are wound around the core 112.

The primary winding 110 includes an excitation inductance 113. One end of the primary winding 110 is electrically connected to one output terminal of the full bridge circuit FB via an inductance 114 and a capacitor 115. The other end of the primary winding 110 is electrically connected to the other output terminal of the full bridge circuit FB. If the excitation inductance 113 is insufficient, an inductance element may be further added.

The full bridge circuit FB outputs a DC voltage Vin, a DC voltage -Vin, or a resonant voltage between one output terminal and the other output terminal. The resonant voltage is a voltage generated by LC resonance caused by the capacitance components of each transistor and the inductance components (excitation inductance 113 and inductance 114).

For example, when transistors Tr1-1 and Tr2-2 are on and transistors Tr2-1 and Tr1-2 are off, the full bridge circuit FB outputs a DC voltage Vin between one output terminal and the other output terminal.

For example, when transistors Tr1-1 and Tr2-2 are in the off state and transistors Tr2-1 and Tr1-2 are in the on state, the full bridge circuit FB outputs a DC voltage -Vin between one output terminal and the other output terminal.

For example, when transistors Tr1-1 to Tr2-2 are in the off state, the full bridge circuit FB outputs a resonant voltage between one output terminal and the other output terminal.

In this disclosure, the LLC resonant circuit is located on the primary winding 110 side, but this is not limited to the above. The LLC resonant circuit may be located on the secondary winding 111 side. The LLC resonant circuit may also be located on both the primary winding 110 side and the secondary winding 111 side.

The rectifier circuit 102 is a bridge diode. The rectifier circuit 102 includes rectifier arms 102-1 and 102-2.

The rectifier arm 102-1 includes a high-side diode D1-1 and a low-side diode D2-1. The anode of the diode D1-1 is electrically connected to the cathode of the diode D2-1.

The connection point between the anode of diode D1-1 and the cathode of diode D2-1 is the input terminal of rectifier arm 102-1. The cathode of diode D1-1 is one output terminal (high potential side) of rectifier arm 102-1. The anode of diode D2-1 is the other output terminal (low potential side) of rectifier arm 102-1.

The rectifier arm 102-2 includes a high-side diode D1-2 and a low-side diode D2-2. The anode of the diode D1-2 is electrically connected to the cathode of the diode D2-2.

The connection point between the anode of diode D1-2 and the cathode of diode D2-2 is the input terminal of rectifier arm 102-2. The cathode of diode D1-2 is one output terminal (high potential side) of rectifier arm 102-2. The anode of diode D2-2 is the other output terminal (low potential side) of rectifier arm 102-2.

The cathodes of diodes D1-1 and D1-2 are electrically connected and form one (high potential side) output terminal of the rectifier circuit 102. The anodes of diodes D2-1 and D2-2 are electrically connected and form the other (low potential side) output terminal of the rectifier circuit 102.

The input terminal of the rectifier arm 102-1 is electrically connected to one end of the secondary winding 111 of the transformer T. The input terminal of the rectifier arm 102-2 is electrically connected to the other end of the secondary winding 111 of the transformer T.

One output terminal (high potential side) of the rectifier circuit 102 is electrically connected to one end (high potential side end) of the capacitor 103. The other output terminal (low potential side) of the rectifier circuit 102 is electrically connected to the other end (low potential side end) of the capacitor 103.

The rectifier circuit 102 full-wave rectifies the voltage excited in the secondary winding 111 and outputs the result to the capacitor 103. The capacitor 103 smoothes the voltage that has been full-wave rectified by the rectifier circuit 102. The voltage of the capacitor 103 is the output voltage Vout.

One end (high potential end) of the capacitor 103 is electrically connected to one end (e.g., the positive electrode of a lithium ion battery) of the load 123. The other end (low potential end) of the capacitor 103 is electrically connected to the other end (e.g., the negative electrode of a lithium ion battery) of the load 123.

The output voltage Vout smoothed by the capacitor 103 is input to the load 123. For example, if the load 123 is a lithium ion battery, the lithium ion battery is charged by the output voltage Vout smoothed by the capacitor 103.

The voltage sensor 104 detects the output voltage Vout and outputs a voltage detection signal to the control unit 106. The current sensor 105 detects the output current Iout flowing through the load 123 and outputs a current detection signal to the control unit 106.

The output setting unit 124 outputs set value signals of the output voltage Vout and the output current Iout to the control unit 106. For example, when the load 123 is a lithium ion battery, the output setting unit 124 outputs a set value signal to the control unit 106 that changes the output voltage Vout from 50 V to 1000 V while maintaining the output current Iout constant at 5 A. Then, when the output voltage Vout reaches 1000 V, the output setting unit 124 outputs a set value signal to the control unit 106 that changes the output current Iout from 5 A to 0 A while maintaining the output voltage Vout constant at 1000 V. The set value signal is exemplified as a signal conforming to CHAdeMO (registered trademark), but the present disclosure is not limited thereto.

Based on the set value signal input from the output setting unit 124, the control unit 106 outputs switching control signals to the gates of transistors Tr1-1 to Tr2-2 so that the output voltage Vout and the output current Iout each reach their set values.

Figure 2 is a diagram showing the relationship between the output current and the output voltage of a power supply device of a comparative example. For example, if the maximum output power of the DC power supply 121 is 5000 W, the maximum output power of the power supply device 100 is 5000 W. Line 131 in Figure 2 is a line showing the locus of operating points when the output power of the power supply device 100 is 5000 W.

The power supply device 100 operates in region 132 (lower in FIG. 2) below line 131, and region 133 (upper in FIG. 2) above line 131 is a non-operating region. Note that the point where the output current is 20 A and the output voltage is 1000 V is the resonance point 134 of the LLC resonant circuit. The frequency of the switching control signal at resonance point 134 is called the resonant frequency. The efficiency of the power supply device 100 is highest at resonance point 134.

The power supply device 100 can lower the output voltage Vout and the output current Iout by increasing the frequency of the switching control signal above the resonant frequency. However, as described above, the efficiency of the power supply device 100 is highest when the switching control signal is at the resonant frequency. Therefore, by increasing the frequency of the switching control signal above the resonant frequency, the efficiency of the power supply device 100 decreases.

Figure 3 shows the time domain waveforms of the drain-source voltage 141 and current 142 of transistor Tr1-1 when the output voltage Vout of the power supply device 100 is 800 V and the output current Iout is 6.25 A. Note that at this time, the frequency of the switching control signal is close to the resonant frequency.

Figure 4 shows the time domain waveforms of the drain-source voltage 151 and current 152 of transistor Tr1-1 when the output voltage Vout of the power supply device 100 is 50 V and the output current Iout is 10 A. Note that at this time, the frequency of the switching control signal is higher than the resonant frequency. Therefore, the time length 154 of one cycle in Figure 4 is shorter than the time length 144 of one cycle in Figure 3.

Referring again to FIG. 2, dotted line 135 is an example of the locus of the operating point of the power supply device 100 when the output voltage Vout is changed from 50 V to 1000 V while the output current Iout is kept constant at 5 A, and when the output voltage Vout reaches 1000 V, the output current Iout is changed from 5 A to 0 A while the output voltage Vout is kept constant at 1000 V. In this case, the power supply device 100 operates with a switching control signal that is higher than the resonant frequency, resulting in low efficiency.

(First embodiment)
Of the components of the power supply device of the first embodiment, the same components as those of the comparative example are given the same reference numerals and description thereof will be omitted.

Figure 5 is a diagram showing the circuit configuration of a power supply device according to the first embodiment. The power supply device 1 receives a DC voltage Vin that is output from a DC power supply 121 and smoothed by a capacitor 122, and outputs an output voltage Vout to a load 123.

The power supply device 1 includes current resonant converters 2-1 to 2-4, a rectifier circuit 3, a control unit 4, a capacitor 103, a voltage sensor 104, and a current sensor 105.

In the first embodiment, the number of current resonant converters is an even number (four as a representative even number), but the present disclosure is not limited to this. The number of current resonant converters may be an odd number. In the first embodiment, the number of current resonant converters is four, but the number of current resonant converters may be two, or six or more.

The current resonant converter 2-1 includes a full bridge circuit FB1 and a transformer T1. The current resonant converter 2-2 includes a full bridge circuit FB2 and a transformer T2. The current resonant converter 2-3 includes a full bridge circuit FB3 and a transformer T3. The current resonant converter 2-4 includes a full bridge circuit FB4 and a transformer T4.

The configuration of each of the current resonant converters 2-1 to 2-4 is similar to that of the current resonant converter 101 (see Figure 1), so a description is omitted.

Note that the maximum output of each of the current resonant converters 2-1 to 2-4 is smaller than that of the current resonant converter 101, but the present disclosure is not limited to this. For example, the maximum output current of each of the current resonant converters 2-1 to 2-4 is one-fourth the maximum output current of the current resonant converter 101, and the maximum output voltage of each of the current resonant converters 2-1 to 2-4 is one-fourth the maximum output voltage of the current resonant converter 101, but the present disclosure is not limited to this.

Rectifier circuit 3 is a bridge diode. Rectifier circuit 3 includes rectifier arms 3-1 to 3-5.

The rectifier arm 3-1 includes a high-side diode D1-1 and a low-side diode D2-1. The anode of the diode D1-1 is electrically connected to the cathode of the diode D2-1.

The connection point between the anode of diode D1-1 and the cathode of diode D2-1 is the input terminal of rectifier arm 3-1. The cathode of diode D1-1 is one output terminal (high potential side) of rectifier arm 3-1. The anode of diode D2-1 is the other output terminal (low potential side) of rectifier arm 3-1.

The rectifier arm 3-2 includes a high-side diode D1-2 and a low-side diode D2-2. The anode of the diode D1-2 is electrically connected to the cathode of the diode D2-2.

The connection point between the anode of diode D1-2 and the cathode of diode D2-2 is the input terminal of rectifier arm 3-2. The cathode of diode D1-2 is one output terminal (high potential side) of rectifier arm 3-2. The anode of diode D2-2 is the other output terminal (low potential side) of rectifier arm 3-2.

The rectifier arm 3-3 includes a high-side diode D1-3 and a low-side diode D2-3. The anode of the diode D1-3 is electrically connected to the cathode of the diode D2-3.

The connection point between the anode of diode D1-3 and the cathode of diode D2-3 is the input terminal of rectifier arm 3-3. The cathode of diode D1-3 is one output terminal (high potential side) of rectifier arm 3-3. The anode of diode D2-3 is the other output terminal (low potential side) of rectifier arm 3-3.

The rectifier arm 3-4 includes a high-side diode D1-4 and a low-side diode D2-4. The anode of the diode D1-4 is electrically connected to the cathode of the diode D2-4.

The connection point between the anode of diode D1-4 and the cathode of diode D2-4 is the input terminal of rectifier arm 3-4. The cathode of diode D1-4 is one output terminal (high potential side) of rectifier arm 3-4. The anode of diode D2-4 is the other output terminal (low potential side) of rectifier arm 3-4.

The rectifier arm 3-5 includes a high-side diode D1-5 and a low-side diode D2-5. The anode of the diode D1-5 is electrically connected to the cathode of the diode D2-5.

The connection point between the anode of diode D1-5 and the cathode of diode D2-5 is the input terminal of rectifier arm 3-5. The cathode of diode D1-5 is one output terminal of rectifier arm 3-5. The anode of diode D2-5 is the other output terminal of rectifier arm 3-5.

The input terminal of the rectifier arm 3-1 is electrically connected to one end 111-1a of the secondary winding 111-1 of the transformer T1. The input terminal of the rectifier arm 3-2 is electrically connected to the other end 111-1b of the secondary winding 111-1 of the transformer T1 and one end 111-2a of the secondary winding 111-2 of the transformer T2. The input terminal of the rectifier arm 3-3 is electrically connected to the other end 111-2b of the secondary winding 111-2 of the transformer T2 and one end 111-3a of the secondary winding 111-3 of the transformer T3. The input terminal of the rectifier arm 3-4 is electrically connected to the other end 111-3b of the secondary winding 111-3 of the transformer T3 and one end 111-4a of the secondary winding 111-4 of the transformer T4. The input terminal of rectifier arm 3-5 is electrically connected to the other end 111-4b of the secondary winding 111-4 of transformer T4.

That is, one output terminal of each of the current resonant converters 2-1 to 2-4 is electrically connected to the other output terminal of the adjacent current resonant converter (one above in FIG. 5), and is also electrically connected to one of the rectifier arms 3-1 to 3-5. For example, one output terminal of the current resonant converter 2-4 (one end 111-4a of the secondary winding 111-4) is electrically connected to the other output terminal (the other end 111-3b of the secondary winding 111-3) of the adjacent current resonant converter 2-3 (one above in FIG. 5), and is also electrically connected to the rectifier arm 3-4. Note that one output terminal of the current resonant converter 2-1 (one end 111-1a of the secondary winding 111-1) is electrically connected alone to the rectifier arm 3-1.

In the present disclosure, adjacent current resonant converters are not limited to being adjacent geographically, but may be adjacent electrically (in terms of wiring). For example, in FIG. 5, current resonant converter 2-1 and current resonant converter 2-2 are not limited to being adjacent geographically. However, from the standpoint of simplifying wiring, reducing wiring length, etc., it is preferable that adjacent current resonant converters are adjacent geographically and adjacent electrically (in terms of wiring).

The cathodes of diodes D1-1 to D1-5 are electrically connected and form one (high potential side) output terminal of rectifier circuit 3. The anodes of diodes D2-1 to D2-5 are electrically connected and form the other (low potential side) output terminal of rectifier circuit 3.

The rectifier circuit 3 full-wave rectifies the voltage excited in the secondary windings 111-1 to 111-4 and outputs the full-wave rectified voltage to the capacitor 103. The capacitor 103 smoothes the voltage that has been full-wave rectified by the rectifier circuit 3. The voltage of the capacitor 103 is the output voltage Vout.

The control unit 4 includes a command unit 41 and a switching unit 42. The command unit 41 outputs command values for the output voltage Vout and the output current Iout to the switching unit 42 based on a set value signal input from the output setting unit 124 so that the output voltage Vout and the output current Iout each become the set value. The switching unit 42 outputs switching control signals from the full bridge circuit FB1 to the full bridge circuit FB4 based on the command value input from the command unit 41.

The switching unit 42 controls each of the full bridge circuits FB1 to FB4 to one of positive polarity output operation, reverse (negative) polarity output operation, and pause.

Figure 6 is a diagram showing the direction of voltage (current) on the secondary winding side of the power supply device of the first embodiment. In detail, Figure 6 is a diagram showing the direction of voltage (current) on the secondary winding side of transformers T1 and T2 when a positive voltage 161 is applied to the primary winding 110-1 of transformer T1 and a positive voltage 162 is applied to the primary winding 110-2 of transformer T2.

In this case, a voltage is generated in the primary winding 110-1 of the transformer T1 in the direction indicated by the arrow 163, and a voltage is generated in the primary winding 110-2 of the transformer T2 in the direction indicated by the arrow 164. Therefore, on the secondary winding side of the transformers T1 and T2, as indicated by the arrow 165, a voltage is generated on the path from diode D2-1 → one end 111-1a of the secondary winding 111-1 of the transformer T1 → the other end 111-1b of the secondary winding 111-1 of the transformer T1 → one end 111-2a of the secondary winding 111-2 of the transformer T2 → the other end 111-2b of the secondary winding 111-2 of the transformer T2 → diode D1-3.

In other words, if the output polarity of one current resonant converter is the same as that of the adjacent current resonant converter, the secondary windings are connected in series (voltage addition).

The control unit 4 can increase (double) the voltage while maintaining the current by controlling the output polarity of one current resonant converter to be the same as that of the adjacent current resonant converter.

Figure 7 is a diagram showing the direction of voltage (current) on the secondary winding side of the power supply device of the first embodiment. In detail, Figure 7 is a diagram showing the direction of voltage (current) on the secondary winding side of transformers T1 and T2 when a positive polarity voltage 171 is applied to the primary winding 110-1 of transformer T1 and a reverse (negative) polarity voltage 172 is applied to the primary winding 110-2 of transformer T2.

In this case, a voltage is generated in the primary winding 110-1 of the transformer T1 in the direction indicated by the arrow 173, and a voltage is generated in the primary winding 110-2 of the transformer T2 in the direction indicated by the arrow 174. Therefore, on the secondary winding side of the transformer T1, as indicated by the arrow 175, a voltage is generated on the path from the diode D2-1 to one end 111-1a of the secondary winding 111-1 of the transformer T1 to the other end 111-1b of the secondary winding 111-1 of the transformer T1 to the diode D1-2. Also, on the secondary winding side of the transformer T2, as indicated by the arrow 176, a voltage is generated on the path from the diode D2-3 to the other end 111-2b of the secondary winding 111-2 of the transformer T2 to one end 111-2a of the secondary winding 111-2 of the transformer T2 to the diode D1-2.

In other words, if the output polarity of one current resonant converter is opposite to that of the adjacent current resonant converter, the secondary windings are connected in parallel (current addition).

The control unit 4 can increase (double) the current while maintaining the voltage by controlling the output polarity of one current resonant converter to be inverse with the output polarity of the adjacent current resonant converter.

Figure 8 shows the relationship between the output current and the output voltage of the power supply device of the first embodiment.

The power supply 1 has operating regions from region 181 to 188. Region 181 is the operating region of the power supply 1 when the current resonant converter 2-1 operates in positive polarity and the current resonant converters 2-2 to 2-4 are at rest. The point where the output current is 5 A and the output voltage is 250 V is the resonance point 191 of the LLC resonant circuit of the current resonant converter 2-1. The efficiency of the current resonant converter 2-1, i.e., the efficiency of the power supply 1, is highest at the resonance point 191.

Area 182 is the operating area of the power supply device 1 when the current resonant converters 2-1 and 2-2 operate with positive polarity and the current resonant converters 2-3 and 2-4 are at rest. Since the output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is the same, the output current Iout is maintained the same as the current when each of the current resonant converters 2-1 and 2-2 is alone. The output voltage Vout is the sum (twice) of the voltages when each of the current resonant converters 2-1 and 2-2 is alone. The point where the output current is 5 A and the output voltage is 500 V is the resonance point 192 of the LLC resonant circuit of the current resonant converters 2-1 and 2-2. The efficiency of the current resonant converters 2-1 and 2-2, that is, the efficiency of the power supply device 1, is highest at the resonance point 192.

Area 183 is the operating area of the power supply device 1 when the current resonant converters 2-1 to 2-3 are operating with positive polarity and the current resonant converter 2-4 is at rest. Since the current resonant converters 2-1 to 2-3 have the same output polarity, the output current Iout is maintained at the same value as the current when each of the current resonant converters 2-1 to 2-3 is operating alone. The output voltage Vout is the sum (three times) of the voltages of each of the current resonant converters 2-1 to 2-3 when operating alone. The point where the output current is 5 A and the output voltage is 750 V is the resonance point 193 of the LLC resonant circuit of the current resonant converters 2-1 to 2-3. The efficiency of the current resonant converters 2-1 to 2-3, i.e., the efficiency of the power supply device 1, is highest at the resonance point 193.

Area 184 is the operating area of the power supply device 1 when the current resonant converters 2-1 to 2-4 operate with positive polarity. Since the current resonant converters 2-1 to 2-4 have the same output polarity, the output current Iout is maintained the same as the current when each of the current resonant converters 2-1 to 2-4 is used alone. The output voltage Vout is the sum (4 times) of the voltages of each of the current resonant converters 2-1 to 2-4 used alone. The point where the output current is 5 A and the output voltage is 1000 V is the resonance point 194 of the LLC resonant circuit of the current resonant converters 2-1 to 2-4. The efficiency of the current resonant converters 2-1 to 2-4, i.e., the efficiency of the power supply device 1, is highest at resonance point 194.

Area 185 is the operating area of the power supply device 1 when the current resonant converter 2-1 operates with positive polarity, the current resonant converter 2-2 operates with reverse (negative) polarity, and the current resonant converters 2-3 and 2-4 are at rest. Since the output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is opposite, the output current Iout is the sum (twice) of the currents of the current resonant converters 2-1 and 2-2 when they are each alone. The output voltage Vout is maintained at the voltage of the current resonant converters 2-1 and 2-2 when they are each alone. The point where the output current is 10 A and the output voltage is 250 V is the resonance point 195 of the LLC resonant circuit of the current resonant converters 2-1 and 2-2. The efficiency of the current resonant converters 2-1 and 2-2, that is, the efficiency of the power supply device 1, is highest at the resonance point 195.

Region 186 is the operating region of the power supply device 1 when the current resonant converters 2-1 and 2-2 operate with positive polarity and the current resonant converters 2-3 and 2-4 operate with reverse (negative) polarity. The output polarity of the current resonant converters 2-1 and 2-2 is the same, the output polarity of the current resonant converters 2-2 and 2-3 is reverse, and the output polarity of the current resonant converters 2-3 and 2-4 is the same. Therefore, the secondary side of the current resonant converter 2-1 and the secondary side of the current resonant converter 2-2 are connected in series (voltage addition). Similarly, the secondary side of the current resonant converter 2-3 and the secondary side of the current resonant converter 2-4 are connected in series (voltage addition). And the secondary side of the current resonant converters 2-1 and 2-2 and the secondary side of the current resonant converters 2-3 and 2-4 are connected in parallel (current addition). Considering the above, the output current Iout is twice the current of each of the current resonant converters 2-1 to 2-4 when used alone. The output voltage Vout is twice the voltage of each of the current resonant converters 2-1 to 2-4 when used alone. The point where the output current is 10 A and the output voltage is 500 V is the resonance point 196 of the LLC resonant circuit of the current resonant converters 2-1 to 2-4. The efficiency of the current resonant converters 2-1 to 2-4, that is, the efficiency of the power supply device 1, is highest at the resonance point 196.

Region 187 is the operating region of the power supply device 1 when the current resonant converters 2-1 and 2-3 operate with positive polarity, the current resonant converter 2-2 operates with reverse (negative) polarity, and the current resonant converter 2-4 is at rest. The output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is opposite, and the output polarity of the current resonant converter 2-2 and the current resonant converter 2-3 is also opposite. Therefore, the secondary side of the current resonant converter 2-1 and the secondary side of the current resonant converter 2-2 are connected in parallel (current addition). Similarly, the secondary side of the current resonant converter 2-2 and the secondary side of the current resonant converter 2-3 are connected in parallel (current addition). In summary, the output current Iout is three times the current when each of the current resonant converters 2-1 to 2-3 is operated individually. In addition, the output voltage Vout is maintained at the voltage when each of the current resonant converters 2-1 to 2-4 is operated individually. The point where the output current is 15 A and the output voltage is 250 V is the resonance point 197 of the LLC resonant circuit of the current resonant converters 2-1 to 2-3. The efficiency of the current resonant converters 2-1 to 2-3, that is, the efficiency of the power supply device 1, is highest at the resonance point 197.

Region 188 is the operating region of the power supply device 1 when the current resonant converters 2-1 and 2-3 operate with positive polarity and the current resonant converters 2-2 and 2-4 operate with reverse (negative) polarity. The output polarity of the current resonant converters 2-1 and 2-2 is reversed, the output polarity of the current resonant converters 2-2 and 2-3 is also reversed, and the output polarity of the current resonant converters 2-3 and 2-4 is also reversed. Therefore, the secondary sides of the current resonant converters 2-1 to 2-4 are connected in parallel (current addition). The output current Iout is four times the current of each of the current resonant converters 2-1 to 2-4 when they are used alone. In addition, the output voltage Vout is maintained at the voltage of each of the current resonant converters 2-1 to 2-4 when they are used alone. The point where the output current is 20 A and the output voltage is 250 V is the resonance point 198 of the LLC resonant circuit of the current resonant converters 2-1 to 2-4. The efficiency of the current resonant converters 2-1 to 2-4, i.e., the efficiency of the power supply device 1, is highest at the resonance point 198.

Figure 9 is a diagram showing the time domain waveforms of the voltage 201 and current 202 between the drain and source of transistor Tr1 from full bridge circuit FB1 to full bridge circuit FB4 when the output voltage Vout of power supply device 1 is 1000 V and the output current Iout is 5 A. In this case, power supply device 1 operates at resonance point 194 in Figure 8. Also, since power supply device 1 operates in region 184 in Figure 8, full bridge circuits FB1 to FB4 operate in phase.

Figure 10 is a diagram showing time domain waveforms of the voltage 211 and current 212 between the drain and source of transistor Tr1 from full bridge circuit FB1 to full bridge circuit FB4 when the output voltage Vout of power supply device 1 is 50 V and the output current Iout is 10 A. Note that at this time, since power supply device 1 operates in region 185 in Figure 8, full bridge circuit FB1 and full bridge circuit FB2 operate in opposite phase, and full bridge circuits FB3 and FB4 are paused.

Referring again to FIG. 8, dotted line 135 is an example of the locus of the operating point of a high-voltage charger when the output voltage Vout is changed from 50 V to 1000 V while the output current Iout is kept constant at 5 A, and when the output voltage Vout reaches 1000 V, the output current Iout is changed from 5 A to 0 A while the output voltage Vout is kept constant at 1000 V. Dotted line 135 passes through resonance points 191 to 194. Therefore, the power supply device 1 operates at the resonance frequency or a frequency close to the resonance frequency, and the decrease in efficiency is suppressed.

As described above, the power supply device 100 has one resonance point, while the power supply device 1 has eight resonance points. Therefore, the power supply device 1 can operate at the resonance frequency or a frequency close to the resonance frequency. This allows the power supply device 1 to suppress reactive current and suppress a decrease in efficiency.

Second Embodiment
Next, a second embodiment will be described, but a description of the comparative example or the same components as those in the first embodiment will be omitted.

Figure 11 is a diagram showing the circuit configuration of a power supply device according to the second embodiment. The power supply device 1A includes current resonant converters 2-1 to 2-3, a rectifier circuit 3A, a control unit 4, a capacitor 103, a voltage sensor 104, and a current sensor 105.

Rectifier circuit 3A is a bridge diode. Rectifier circuit 3 includes rectifier arms 3-1 to 3-4.

In the second embodiment, the number of current resonant converters is three, which is a representative odd number, but the present disclosure is not limited to this. The number of current resonant converters may be five or more.

Figure 12 shows the relationship between the output current and the output voltage of the power supply device of the second embodiment.

The power supply 1A has operating regions from region 221 to region 225. Region 221 is the operating region of the power supply 1A when the current resonant converter 2-1 operates in positive polarity and the current resonant converters 2-2 and 2-3 are at rest. The point where the output current is 5 A and the output voltage is 250 V is the resonance point 231 of the LLC resonant circuit of the current resonant converter 2-1. The efficiency of the current resonant converter 2-1, i.e., the efficiency of the power supply 1A, is highest at the resonance point 231.

Area 222 is the operating area of the power supply device 1A when the current resonant converters 2-1 and 2-2 operate with positive polarity and the current resonant converter 2-3 is at rest. Since the output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is the same, the output current Iout is maintained the same as the current when each of the current resonant converters 2-1 and 2-2 is alone. The output voltage Vout is the sum (twice) of the voltages when each of the current resonant converters 2-1 and 2-2 is alone. The point where the output current is 5 A and the output voltage is 500 V is the resonance point 232 of the LLC resonant circuit of the current resonant converters 2-1 and 2-2. The efficiency of the current resonant converters 2-1 and 2-2, that is, the efficiency of the power supply device 1A, is highest at the resonance point 232.

Area 223 is the operating area of the power supply device 1A when the current resonant converters 2-1 to 2-3 operate with positive polarity. Since the current resonant converters 2-1 to 2-3 have the same output polarity, the output current Iout is maintained the same as the current when each of the current resonant converters 2-1 to 2-3 is used alone. The output voltage Vout is the sum (three times) of the voltages of each of the current resonant converters 2-1 to 2-3 when used alone. The point where the output current is 5A and the output voltage is 750V is the resonance point 233 of the LLC resonant circuit of the current resonant converters 2-1 to 2-3. The efficiency of the current resonant converters 2-1 to 2-3, i.e., the efficiency of the power supply device 1A, is highest at the resonance point 233.

Area 224 is the operating area of the power supply device 1A when the current resonant converter 2-1 operates with positive polarity, the current resonant converter 2-2 operates with reverse (negative) polarity, and the current resonant converter 2-3 is at rest. Since the output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is opposite, the output current Iout is the sum (twice) of the currents of the current resonant converters 2-1 and 2-2 when they are each alone. The output voltage Vout is maintained at the voltage of the current resonant converters 2-1 and 2-2 when they are each alone. The point where the output current is 10 A and the output voltage is 250 V is the resonance point 234 of the LLC resonant circuit of the current resonant converters 2-1 and 2-2. The efficiency of the current resonant converters 2-1 and 2-2, that is, the efficiency of the power supply device 1A, is highest at the resonance point 234.

Region 225 is the operating region of the power supply device 1A when the current resonant converters 2-1 and 2-3 operate with positive polarity and the current resonant converter 2-2 operates with reverse (negative) polarity. The output polarity of the current resonant converter 2-1 and the current resonant converter 2-2 is reversed, and the output polarity of the current resonant converter 2-2 and the current resonant converter 2-3 is also reversed. Therefore, the secondary side of the current resonant converter 2-1 and the secondary side of the current resonant converter 2-2 are connected in parallel (current addition). Similarly, the secondary side of the current resonant converter 2-2 and the secondary side of the current resonant converter 2-3 are connected in parallel (current addition). In summary, the output current Iout is three times the current when each of the current resonant converters 2-1 to 2-3 is used alone. In addition, the output voltage Vout is maintained at the voltage when each of the current resonant converters 2-1 to 2-4 is used alone. The point where the output current is 15 A and the output voltage is 250 V is the resonance point 235 of the LLC resonant circuit of the current resonant converters 2-1 to 2-3. The efficiency of the current resonant converters 2-1 to 2-3, that is, the efficiency of the power supply device 1A, is highest at the resonance point 235.

As described above, power supply unit 100 has one resonance point, while power supply unit 1A has five resonance points. Therefore, power supply unit 1A can operate at the resonance frequency or a frequency close to the resonance frequency. This allows power supply unit 1A to suppress reactive current and suppress a decrease in efficiency.

Third Embodiment
Next, the third embodiment will be described, but the description of the same components as those in the comparative example, first or second embodiment will be omitted.

Figure 13 is a diagram showing the circuit configuration of a power supply device according to the third embodiment. In the power supply device 1B according to the third embodiment, the diodes on the low side of each rectifier arm are replaced with switching elements (synchronous rectifier elements) from the viewpoint of reducing losses, etc., and synchronous rectification is performed. This is because the loss when the switching elements are in the on state is less than the loss of the diodes.

Compared to the power supply device 1 of the first embodiment (see FIG. 5), the power supply device 1B includes a rectifier circuit 3B instead of the rectifier circuit 3. Also, compared to the power supply device 1, the power supply device 1B further includes a reset pulse generating circuit 5 and drive circuits 6-1 to 6-5.

Rectification circuit 3B includes rectification arms 3-1B to 3-5B.

Compared to the rectifier arm 3-1 (see FIG. 5), the rectifier arm 3-1B includes a switching element SW-1 and a current sensor 10-1 instead of the diode D2-1.

Compared to the rectifier arm 3-2 (see FIG. 5), the rectifier arm 3-2B includes a switching element SW-2 and a current sensor 10-2 instead of the diode D2-2.

Compared to the rectifier arm 3-3 (see FIG. 5), the rectifier arm 3-3B includes a switching element SW-3 and a current sensor 10-3 instead of the diode D2-3.

Compared to the rectifier arm 3-4 (see FIG. 5), the rectifier arm 3-4B includes a switching element SW-4 and a current sensor 10-4 instead of the diode D2-4.

Compared to the rectifier arm 3-5 (see FIG. 5), the rectifier arm 3-5B includes a switching element SW-5 and a current sensor 10-5 instead of the diode D2-5.

Switching elements SW-1 to SW-5 are transistors, but this disclosure is not limited to this.

Hereinafter, switching elements SW-1 to SW-5 may be collectively referred to as "switching elements SW." Diodes D1-1 to D1-5 may be collectively referred to as "diode D1." Transformers T1 to T4 may be collectively referred to as "transformer T." Current resonant converters 2-1 to 2-4 may be collectively referred to as "current resonant converter 2."

In order to output a switching control signal for switching the switching element SW, Rogowski coils are used as the current sensors 10-1 to 10-5. The Rogowski coil induces a voltage at both ends according to the current. This voltage is the derivative of the current. Therefore, the current can be measured by integrating this voltage with an integrating circuit. The integral value of the integrating circuit must be reset at an appropriate timing. The driving circuits 6-1 to 6-5 integrate the output signals of the current sensors 10-1 to 10-5, respectively, and reset the integral values based on the reset pulse signal _S0 supplied from the reset pulse generating circuit 5.

The reset pulse generating circuit 5 is electrically connected to the anode of the diode D1-1 and the drain of the switching element SW-1 via a capacitor 7 and a resistor 8. The reset pulse generating circuit 5 outputs a reset pulse signal _S0 to the drive circuits 6-1 to 6-5 based on a voltage _V1 at the anode of the diode D1-1 and the drain of the switching element SW-1. For example, the reset pulse generating circuit 5 outputs the reset pulse signal _S0 based on the differentiation of the voltage _V1 .

Figure 14 is a diagram showing the circuit configuration of the drive circuit of the power supply device of the third embodiment. Figure 14 shows the circuit configuration of drive circuit 6-1. The circuit configurations of drive circuits 6-2, 6-3, 6-4, and 6-5 are similar to the circuit configuration of drive circuit 6-1, so illustrations and explanations are omitted.

The drive circuit 6-1 includes an integrating circuit 20, a comparator 31, a reference voltage source 32, and an output circuit 33. The integrating circuit 20 includes an operational amplifier 21, a resistor 22, a capacitor 23, and a transfer gate circuit 24.

One end of the current sensor 10-1 is electrically connected to the non-inverting input terminal (+ terminal) of the operational amplifier 21. The other end of the current sensor 10-1 is electrically connected to the inverting input terminal (- terminal) of the operational amplifier 21.

The resistor 22 is electrically connected between the inverting input terminal of the operational amplifier 21 and the output terminal of the operational amplifier 21. The capacitor 23 is electrically connected between the inverting input terminal of the operational amplifier 21 and the output terminal of the operational amplifier 21. In other words, the operational amplifier 21 is negatively fed back by the resistor 22 and the capacitor 23. The charge of the capacitor 23 corresponds to the integral value of the output signal of the current sensor 10-1.

The transfer gate circuit 24 is electrically connected between the inverting input terminal of the operational amplifier 21 and the output terminal of the operational amplifier 21. When the reset pulse signal _S0 is supplied from the reset pulse generating circuit 5, the transfer gate circuit 24 shorts both ends of the capacitor 23. This resets the charge of the capacitor 23, i.e., the integral value of the output signal of the current sensor 10-1.

The inverting input terminal (- terminal) of the comparator 31 is electrically connected to the reference voltage source 32. The non-inverting input terminal (+ terminal) of the comparator 31 is electrically connected to the output terminal of the operational amplifier 21. The comparator 31 outputs a high-level signal when the output voltage of the operational amplifier 21 becomes equal to or higher than the voltage of the reference voltage source 32. The output circuit 33 amplifies the output signal of the comparator 31, and outputs a switching control signal _S1 to the gate of the switching element SW-1. This causes the switching element SW-1 to be turned on.

Referring again to FIG. 13, oscillations (ringing) may occur in the voltage between the high-side diode D1 and the low-side switching element SW in rectifier arms 3-1B to 3-5B.

The ringing that occurs in the voltage of the rectifier arms 3-1B to 3-5B where current flows between them and capacitor 103 (current flows in and out of capacitor 103) is caused by the leakage inductance of transformer T and the capacitance of capacitor 103. The frequency of the ringing is lower than the switching frequency of current resonant converter 2 because the capacitance of capacitor 103 is large. Therefore, the ringing is not observed as a waveform.

On the other hand, ringing occurs in the voltage of rectifier arms 3-1B to 3-5B where no current flows between them and capacitor 103 (no current flows in or out of capacitor 103) due to the leakage inductance of transformer T and the parasitic capacitance of diode D1. The frequency of the ringing is higher than the switching frequency of current resonant converter 2 because the parasitic capacitance of diode D1 is small. Therefore, the ringing is observed as a waveform.

Therefore, if the reset pulse generating circuit 5 were to generate the reset pulse signal _S0 based on the voltage of the rectifier arm in which no current flows between the capacitor 103 and the ringing waveform, the ringing waveform would be differentiated, resulting in the reset pulse signal _S0 being generated at an unintended timing. As a result, the drive circuits 6-1 to 6-5 would be unable to detect the current correctly (would be unable to integrate correctly), and would therefore be unable to drive the switching element SW at an appropriate timing.

The control unit 4 operates the current resonant converter 2 in an operation pattern that always operates the current resonant converter 2-1 (or 2-4) at the extreme end (one end or the other end). The reset pulse generating circuit 5 is then electrically connected to the rectifier arm 3-1B (or 3-5B) at the extreme end (one end or the other end). For example, as shown in FIG. 13, the reset pulse generating circuit 5 is electrically connected to the rectifier arm 3-1B.

Figure 15 is a diagram showing an operating pattern of a power supply device according to a third embodiment, which always operates a current resonant converter at one end, and a rectifier arm through which a current flows between the capacitor. In Figure 15, "on" indicates a rectifier arm through which a current flows between the capacitor 103. "off" indicates a rectifier arm through which no current flows between the capacitor 103.

As shown in FIG. 15(a), in the case of an operating pattern in which current resonant converters 2-1 to 2-4 operate in positive polarity, current flows between rectifier arms 3-1B and 3-5B and capacitor 103. No current flows between rectifier arms 3-2B, 3-3B, and 3-4B and capacitor 103.

As shown in FIG. 15(b), in the case of an operation pattern in which current resonant converters 2-1 to 2-3 operate in positive polarity and current resonant converter 2-4 is at rest, current flows between rectifier arms 3-1B and 3-4B and capacitor 103. No current flows between rectifier arms 3-2B, 3-3B, and 3-5B and capacitor 103.

As shown in FIG. 15(c), in the case of an operation pattern in which the current resonant converters 2-1 and 2-2 operate in positive polarity and the current resonant converters 2-3 and 2-4 are at rest, current flows between the rectifier arms 3-1B and 3-3B and the capacitor 103. No current flows between the rectifier arms 3-2B, 3-4B, and 3-5B and the capacitor 103.

As shown in FIG. 15(d), in the case of an operation pattern in which current resonant converter 2-1 operates in positive polarity and current resonant converters 2-2 to 2-4 are at rest, current flows between rectifier arms 3-1B and 3-2B and capacitor 103. No current flows between rectifier arms 3-3B, 3-4B, and 3-5B and capacitor 103.

As shown in FIG. 15(e), in the case of an operating pattern in which the current resonant converters 2-1 and 2-2 operate with positive polarity and the current resonant converters 2-3 and 2-4 operate with reverse polarity, current flows between the rectifier arms 3-1B, 3-3B, and 3-5B and the capacitor 103. No current flows between the rectifier arms 3-2B and 3-4B and the capacitor 103.

As shown in FIG. 15(f), in the case of an operation pattern in which the current resonant converter 2-1 operates with positive polarity, the current resonant converter 2-2 operates with reverse polarity, and the current resonant converters 2-3 and 2-4 are at rest, current flows between the rectifier arms 3-1B, 3-2B, and 3-3B and the capacitor 103. No current flows between the rectifier arms 3-4B and 3-5B and the capacitor 103.

As shown in FIG. 15(g), in the case of an operating pattern in which current resonant converters 2-1 and 2-3 operate in positive polarity, current resonant converter 2-2 operates in reverse polarity, and current resonant converter 2-4 is at rest, current flows between rectifier arms 3-1B to 3-4B and capacitor 103. No current flows between rectifier arm 3-5B and capacitor 103.

As shown in FIG. 15(h), in the case of an operating pattern in which current resonant converters 2-1 and 2-3 operate with positive polarity and current resonant converters 2-2 and 2-4 operate with reverse polarity, current flows between rectifier arms 3-1B to 3-5B and capacitor 103.

Figures 16 and 17 show the operating pattern of the power supply device of the third embodiment that always operates the current resonant converter at one end, and the voltage of the rectifier arm.

As shown in FIG. 16(a), in the case of an operating pattern in which current resonant converters 2-1 to 2-4 operate in positive polarity, current flows between rectifier arm 3-1B and capacitor 103. Therefore, ringing is not observed as a waveform in rectifier arm 3-1B.

As shown in FIG. 16(b), in the case of an operating pattern in which current resonant converters 2-1 to 2-3 operate in positive polarity and current resonant converter 2-4 is at rest, current flows between rectifier arm 3-1B and capacitor 103. Therefore, ringing is not observed as a waveform in rectifier arm 3-1B.

As shown in FIG. 16(c), in the case of an operating pattern in which the current resonant converters 2-1 and 2-2 operate in positive polarity and the current resonant converters 2-3 and 2-4 are at rest, a current flows between the rectifier arm 3-1B and the capacitor 103. Therefore, no ringing is observed as a waveform in the rectifier arm 3-1B.

As shown in FIG. 16(d), in the case of an operating pattern in which current resonant converter 2-1 operates in positive polarity and current resonant converters 2-2 to 2-4 are at rest, current flows between rectifier arm 3-1B and capacitor 103. Therefore, ringing is not observed as a waveform in rectifier arm 3-1B.

As shown in FIG. 17(e), in the case of an operating pattern in which the current resonant converters 2-1 and 2-2 operate with positive polarity and the current resonant converters 2-3 and 2-4 operate with reverse polarity, a current flows between the rectifier arm 3-1B and the capacitor 103. Therefore, ringing is not observed as a waveform in the rectifier arm 3-1B.

As shown in FIG. 17(f), in the case of an operating pattern in which the current resonant converter 2-1 operates with positive polarity, the current resonant converter 2-2 operates with reverse polarity, and the current resonant converters 2-3 and 2-4 are at rest, a current flows between the rectifier arm 3-1B and the capacitor 103. Therefore, ringing is not observed as a waveform in the rectifier arm 3-1B.

As shown in FIG. 17(g), in the case of an operating pattern in which the current resonant converters 2-1 and 2-3 operate in positive polarity, the current resonant converter 2-2 operates in reverse polarity, and the current resonant converter 2-4 is at rest, a current flows between the rectifier arm 3-1B and the capacitor 103. Therefore, ringing is not observed as a waveform in the rectifier arm 3-1B.

As shown in FIG. 17(h), in the case of an operating pattern in which the current resonant converters 2-1 and 2-3 operate with positive polarity and the current resonant converters 2-2 and 2-4 operate with reverse polarity, a current flows between the rectifier arm 3-1B and the capacitor 103. Therefore, ringing is not observed as a waveform in the rectifier arm 3-1B.

This allows the reset pulse generating circuit 5 to generate the reset pulse signal _S0 at an appropriate timing without being affected by ringing. Therefore, in the rectifier circuit 3B, the low-side diodes D2-1 to D2-5 (see FIG. 5) can be replaced with the switching elements SW-1 to SW-5.

In this way, the diodes D2-1 to D2-5 on the low side of the rectifier circuit 3B can be replaced with the switching elements SW-1 to SW-5. The loss when the switching elements SW-1 to SW-5 are in the on state is less than the loss in the diodes D2-1 to D2-5. This allows the power supply device 1B to suppress the loss in the rectifier circuit 3B, thereby suppressing a decrease in efficiency.

In the third embodiment, the number of current resonant converters is an even number (four as a representative even number), but the present disclosure is not limited to this. The number of current resonant converters may be an odd number. In the third embodiment, the number of current resonant converters is four, but the number of current resonant converters may be two, or six or more.

In addition, in the third embodiment, a case has been described in which the low-side diode of each rectifier arm is replaced with a switching element, but the present disclosure is not limited to this. The high-side diode of each rectifier arm may also be replaced with a switching element.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and gist of the invention.

1, 1A, 1B, 100 Power supply device 2-1, 2-2, 2-3, 2-4, 101 Current resonant converter 3, 3A, 3B, 102 Rectifier circuit 4 Control unit 5 Reset pulse generating circuit 6-1, 6-2, 6-3, 6-4, 6-5 Drive circuit 41 Command unit 42 Switching unit D1-1, D1-2, D1-3, D1-4, D1-5 Diodes FB, FB1, FB2, FB3, FB4 Full bridge circuit SW-1, SW-2, SW-3, SW-4, SW-5 Switching elements T, T1, T2, T3, T4 Transformer 103, 122 Capacitor 104 Voltage sensor 105 Current sensor 106 Control unit 121 DC power supply 123 Load 124 Output setting unit

Claims (7)

A plurality of current resonant converters;
a rectifier circuit including a plurality of rectifier arms each including one of a rectifier element and a switching element on a high side and the other of a rectifier element and a switching element on a low side, and rectifying output voltages of the plurality of current resonant converters and outputting the rectified output voltages to a load;
A control circuit for controlling the plurality of current resonant converters;
a plurality of current sensors each detecting a current flowing through the plurality of rectifier arms;
a plurality of drive circuits each outputting a drive signal for operating the switching element of each of the rectifier arms based on an integral value obtained by integrating an output signal of each of the current sensors;
a reset pulse output circuit that outputs a reset pulse for resetting an integral value of the plurality of driving circuits;
Equipped with
One output terminal of each of the plurality of current resonant converters is electrically connected to the other output terminal of each adjacent current resonant converter and is also electrically connected to one rectifier arm of the plurality of rectifier arms;
The control circuit includes:
A current resonant converter at one end or the other end of the plurality of current resonant converters is always operated, and each of the remaining current resonant converters of the plurality of current resonant converters is controlled to any one of a positive polarity output operation, a negative polarity output operation, and a pause;
The reset pulse output circuit includes:
outputting the reset pulse based on a voltage between the rectifier element and the switching element of a rectifier arm at one end or the other end of the plurality of rectifier arms;
A power supply device comprising: The reset pulse output circuit includes:
outputting the reset pulse based on a voltage between the rectifier element on a high side or a low side of a rectifier arm at one end or the other end of the plurality of rectifier arms and the switching element on a low side or a high side;
2. The power supply device according to claim 1 . The current sensor is a Rogowski coil.
3. The power supply device according to claim 1 or 2. The control circuit includes:
performing control to increase an output voltage to the load from a predetermined first voltage to a predetermined second voltage while maintaining an output current to the load at a predetermined first current;
4. The power supply device according to claim 1, wherein the power supply device is a power supply unit. The control circuit includes:
After the output voltage reaches the second voltage, a control is performed to reduce the output current from the first current while maintaining the output voltage at the second voltage.
5. The power supply device according to claim 4. the number of the current resonant converters is an even number;
6. A power supply device according to claim 1, wherein the power supply device is a power supply unit. the number of the current resonant converters is an odd number;
6. A power supply device according to claim 1, wherein the power supply device is a power supply unit.

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