JP6089281B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device.

  AC devices such as air conditioners, refrigerators, and washing machines that use high power are driven by commercial power (AC power), and DC devices such as personal computers, LCD TVs, telephones, and facsimiles operate with DC power, In stores, techniques for coexistence of an AC power distribution system that supplies AC power and a DC power distribution system that supplies DC power have been proposed.

  In general, as a DC power source used by a DC power distribution system, an AC-DC converter that converts an AC power source into a DC power source is used as shown in Patent Document 1, and the DC power output from the AC-DC converter is a DC power circuit. To be supplied to the DC device. Furthermore, it is possible to store DC surplus power in the secondary battery and supply the stored power to the DC circuit. For example, when a distributed power source composed of a solar cell or the like is used as a DC power source, the solar cell can use daytime sunlight, but cannot be used at night or in bad weather. Therefore, electric power from sunlight during the day is stored in the secondary battery, and DC power of the secondary battery is supplied to the DC circuit as needed at night.

JP 2009-27877 A

  The conventional AC-DC converter performs a boosting operation to improve the power factor, and an inductor for boosting is required in the circuit. Further, a filter is provided at the input stage of the AC-DC converter for noise suppression, and the AC power is input through this filter.

  In addition, when the output of the AC-DC converter is a DC voltage of about DC300V, it is necessary to step down to a low voltage such as DC48V in order to use it in a DC device. DC-DC converters are provided, and it is necessary to provide a filter at the input stage of the DC-DC converter as a countermeasure against noise.

  Therefore, the size of the AC-DC converter is increased by an inductor for boosting and a filter for noise suppression. Further, when a DC-DC converter for voltage reduction is provided, a filter for noise suppression is further required. It was. Further, when a separate AC-DC converter and a step-down DC-DC converter are used, the burden on the user is large due to cost, size, and conversion loss between both converters.

  The present invention has been made in view of the above-described reasons, and an object of the present invention is to provide a step-up function that converts an AC voltage into a first DC voltage, and a step-down function that converts a first DC voltage into a second DC voltage. It is providing the power converter device which aimed at size reduction and cost reduction.

The first aspect of the present invention includes a rectifying unit that converts an AC voltage from an AC power source into a first DC voltage, and turns on or off a switching element that constitutes the rectifying unit, whereby the first AC voltage is supplied. An AC-DC converter configured to be able to switch between a first operation for converting to a direct current voltage and outputting, and a second operation for reversely converting the first direct current voltage to an alternating voltage, DC converter means for stepping down one DC voltage to a second DC voltage is provided, and the first DC voltage is changed to the second DC voltage by turning on and off the switching elements constituting the DC converter means. A DC-DC converter configured to be switchable between a third operation for conversion and output, and a fourth operation for reversely converting the second DC voltage to the first DC voltage, and the AC Inserted between the power supply and the AC-DC converter A filter unit including an inductor, and the AC-DC conversion unit and the DC-DC conversion unit are integrally provided in the same casing, and the AC-DC conversion unit is a switching unit that constitutes the rectification unit. The element is turned on and off to store and discharge energy in the inductor of the filter unit to perform a boosting operation, thereby converting an AC voltage into a first DC voltage, and the DC-DC conversion units are magnetically coupled to each other. A transformer having a pair of coils is provided between the first DC voltage side and the second DC voltage side, and a series circuit of a capacitor and an inductor is connected in series to one of the pair of coils. are connected, said from the impedance element in the filter unit AC devices via the derived path from AC-DC converter unit side is connected, the impedance of the filter section, before When the AC-DC converter performs the second operation, the AC-DC converter increases more than when the AC-DC converter performs the first operation, and the switching element of the AC-DC converter is a bidirectional switch. It is characterized by that.

According to the present invention, the inductor of the filter unit is used for boosting while having a boosting function for converting an AC voltage into a first DC voltage and a step-down function for converting a first DC voltage into a second DC voltage. By sharing the inductor, it is possible to reduce the size and cost. In addition, it is not necessary to separately provide a configuration for reverse conversion from the DC power distribution system to the AC power distribution system, and the configuration is simplified and the cost is reduced by using both the AC-DC conversion means and the DC-AC conversion means. Can be achieved. In addition, since the AC-DC conversion unit and the DC-DC conversion unit are integrally configured, the filter unit, the switching control unit, the protection circuit, and the like can be used together, and the power conversion device can be reduced in size and cost, and the switching element. The drive control circuit can be simplified. Furthermore, conversion loss between the AC-DC converter and the DC-DC converter is also reduced. In addition, it becomes difficult to supply the reversely converted power to the AC power supply side, and the reversely converted power is efficiently supplied to the AC device connected to the electric circuit derived from the AC-DC conversion unit side from the impedance element in the filter unit. can do. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system. Furthermore, loss during rectification is reduced, and efficiency can be improved.

  According to a second aspect of the present invention, in the first aspect, the filter unit includes the impedance element having a variable impedance, and an impedance control unit that controls the impedance of the impedance element. The impedance when the AC-DC converter performs the second operation is set larger than the impedance when the first operation is performed.

  According to the present invention, it is difficult to supply the reversely converted power to the AC power supply side, and the reversely converted power is supplied to the AC device connected to the electrical circuit derived from the AC-DC conversion unit side from the impedance element in the filter unit. Can be supplied efficiently. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system. On the other hand, when the AC-DC converter performs the first operation, the input efficiency of the AC power supplied to the AC-DC converter can be increased.

  According to a third aspect of the present invention, in the first aspect, the AC-DC converter reversely converts the first DC voltage into an AC voltage having a frequency higher than the frequency of the AC power source when performing the second operation. The AC device is connected via an electric circuit that outputs and is derived from an inductor in the filter unit from the AC-DC conversion unit side.

  According to the present invention, since the frequency of the AC power to be reversely converted is increased, the impedance of the inductor of the filter unit is increased, and it is difficult for the reversely converted power to flow to the AC power source side. The reversely converted AC power can be efficiently supplied to the AC device connected to the electric circuit derived from the conversion unit side. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system.

  As described above, the present invention has a step-up function that converts an AC voltage into a first DC voltage and a step-down function that converts a first DC voltage into a second DC voltage. There is an effect that the cost can be reduced. In addition, it is not necessary to separately provide a configuration for reverse conversion from the DC power distribution system to the AC power distribution system, and the configuration is simplified and the cost is reduced by using both the AC-DC conversion means and the DC-AC conversion means. Can be achieved. In addition, since the AC-DC conversion unit and the DC-DC conversion unit are integrally configured, the filter unit, the switching control unit, the protection circuit, and the like can be used together, and the power conversion device can be reduced in size and cost, and the switching element. The drive control circuit can be simplified. Furthermore, conversion loss between the AC-DC converter and the DC-DC converter is also reduced. In addition, it becomes difficult to supply the reversely converted power to the AC power supply side, and the reversely converted power is efficiently supplied to the AC device connected to the electric circuit derived from the AC-DC conversion unit side from the impedance element in the filter unit. can do. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system.

It is a figure which shows the structure of the filter part of Embodiment 3. It is a figure which shows the structure of the power converter device of Embodiment 1. FIG. It is a figure which shows the structure of the power converter device of Embodiment 2. FIG. It is a figure which shows the structure of the filter part of Embodiment 4. (A)-(d) It is a figure which shows each waveform before and behind the filter of the alternating voltage by which the reverse conversion of Embodiment 5 is carried out.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 2 shows a configuration of the power conversion device (bidirectional AC-DC converter) of the present embodiment, and a filter unit 1 to which an AC power source (commercial power source) AC is connected, and an AC power source via the filter unit 1. An AC-DC converter 2 that converts the AC voltage Vac of the AC power supply AC into a DC voltage V1 (first DC voltage) connected to AC and a smoothing connected between the output terminals of the AC-DC converter 2 Capacitor Ca, DC-DC converter 3 that steps down DC voltage V1 output from AC-DC converter 2 to DC voltage V2 (second DC voltage), AC-DC converter 2, and DC-DC It comprises a switching control unit 4 that performs switching control of the conversion unit 3, and the filter unit 1, the AC-DC conversion unit 2, the DC-DC conversion unit 3, the switching control unit 4, and the capacitor Ca are integrated in the same casing ( For example, the same group On, it is formed on the same block).

  The AC power source AC is a single-phase three-wire 100V / 200V, 50/60 Hz commercial power source, and AC power is supplied to AC devices such as air conditioners, refrigerators, and washing machines via a pair of AC electric circuits Wac disposed in a house. Supply.

The filter unit 1 is provided on the AC side of the AC-DC conversion unit 2, and includes a capacitor C1 connected between the AC circuit Wac and inductors L11 and L12 connected in series to the AC circuit Wac. Wac passes through the filter unit 1 and is connected to the AC - DC conversion unit 2.

  The AC-DC conversion unit 2 includes a parallel circuit of switching elements Q1 and Q2 connected in series and switching elements Q3 and Q4 connected in series, and the switching control unit 4 drives the switching elements Q1 to Q4 individually on and off. The AC circuit Wac is connected via the filter unit 1 to the connection midpoint of the switching elements Q1 and Q2 and the connection midpoint of the switching elements Q3 and Q4. The switching elements Q1 to Q4 are configured by N-type MOSFETs, and body diodes D1 to D4 (hereinafter referred to as diodes D1 to D4) are configured in reverse parallel to the switching elements Q1 to Q4.

  Next, the AC-DC conversion function of the AC-DC conversion unit 2 will be described. The AC-DC converter 2 rectifies and boosts the AC voltage Vac (AC100V / 200V) to generate a DC voltage V1 (DC300V) across the capacitor Ca. The inductor of the filter unit 1 serves as a boosting inductor. L11 and L12 are used. Here, diodes D1 to D4 constitute a full-bridge rectifier circuit, and switching elements Q2 and Q4, diodes D1 and D3, and inductors L11 and L12 constitute a boost chopper circuit.

  First, when the AC voltage Vac is a positive voltage and the switching elements Q1 to Q4 are in the OFF state, the current flows through the path of the AC power supply AC → the inductor L11 → the diode D3 → the capacitor Ca → the diode D2 → the inductor L12 → the AC power supply AC. Although it flows, the switching control part 4 keeps switching element Q1-Q3 in an OFF state, and repeats ON / OFF of switching element Q4. When the switching element Q4 is turned on, current flows through the inductors L11 and L12 through the path of AC power supply AC → inductor L11 → switching element Q4 → diode D2 → inductor L12 → AC power supply AC, and energy is stored in the inductors L11 and L12. . When the switching element Q4 is turned off, the energy accumulated in the inductors L11 and L12 is released through the diode D3, and charges the capacitor Ca. Thus, by repeatedly turning on / off the switching element Q4 when the AC voltage Vac is a positive voltage, the voltage across the capacitor Ca is greater than the rectified voltage obtained by full-wave rectifying the AC voltage Vac with the diodes D1 to D4. It becomes a boosted voltage.

  Next, when the AC voltage Vac is a negative voltage and the switching elements Q1 to Q4 are in the OFF state, the current flows through the path of the AC power supply AC → the inductor L12 → the diode D1 → the capacitor Ca → the diode D4 → the inductor L11 → the AC power supply AC. However, the switching control unit 4 keeps the switching elements Q1, Q3, and Q4 in the off state and repeatedly turns on and off the switching element Q2. When the switching element Q2 is turned on, current flows through the inductors L11 and L12 through the path of AC power supply AC → inductor L12 → switching element Q2 → diode D4 → inductor L11 → AC power supply AC, and energy is stored in the inductors L11 and L12. . When the switching element Q2 is turned off, the energy stored in the inductors L11 and L12 is released through the diode D1 to charge the capacitor Ca. Thus, by repeatedly turning on and off the switching element Q2 when the AC voltage Vac is a negative voltage, the DC voltage V1 generated at both ends of the capacitor Ca becomes the full-wave rectification of the AC voltage Vac by the diodes D1 to D4. It becomes a value boosted from the rectified voltage.

  Thus, the switching control unit 4 feeds back the voltage across the capacitor Ca and controls the on / off driving of the switching elements Q1 to Q4 so that the DC voltage V1 = DC300V. In FIG. 2, the feedback path of the voltage across the capacitor Ca is omitted.

  As described above, the AC-DC converter 2 has a boosting function for converting the AC voltage Vac to the DC voltage V1, and also functions as a power factor correction circuit (PFC) by the boosting operation (first operation). . By using the inductors L11 and L12 of the filter unit 1 as the boosting inductor, it is possible to reduce the size and cost.

Next, in the DC-DC converter 3, the parallel circuit of the switching elements Q7 and Q8 connected in series with the switching elements Q5 and Q6 connected in series is connected between both ends of the capacitor Ca, and the switching elements Q5 and Q6 are being connected. A series circuit of a primary winding N1 of the transformer T1, a capacitor Cs, and an inductor Ls is connected between the point and the connection middle point of the switching elements Q7 and Q8. Further, a parallel circuit of the switching elements Q11 and Q12 connected in series with the switching elements Q9 and Q10 connected in series is connected between both ends of the smoothing capacitor Cb, and the connection midpoint of the switching elements Q9 and Q10 and the switching elements Q11, Q10, Between the connection midpoint of Q12, the secondary winding N2 of the transformer T1 is connected. The switching elements Q5 to Q12 are individually turned on / off by the switching control unit 4. The switching elements Q5 to Q12 are N-type MOSFETs, and body diodes D5 to D12 (hereinafter referred to as diodes D5 to D12) are configured in reverse parallel to the switching elements Q5 to Q12.

  The capacitor Cs and the inductor Ls form a series resonance circuit, and the switching control unit 4 alternately turns on / off the switching elements Q5, Q8 and the switching elements Q6, Q7, thereby providing the primary winding N1. An alternating voltage is generated and an alternating voltage is induced in the secondary winding N2. The switching control unit 4 maintains the switching elements Q9 to Q12 in the off state, and the alternating voltage induced in the secondary winding N2 is full-wave rectified by the diodes D9 to D12 and generates a DC voltage V2 across the capacitor Cb. And output to the DC circuit Wdc (second operation). The switching control unit 4 feeds back the voltage across the capacitor Cb and controls the on / off driving of the switching elements Q5 to Q8 so that the DC voltage V2 = DC48V. In this way, the DC-DC converter 3 steps down the direct-current voltage V1 (DC300V) to the direct-current voltage V2 (DC48V) and supplies the direct-current voltage Vdc to the house. A DC device such as a personal computer, a liquid crystal television, a telephone, and a facsimile is connected to the DC circuit Vdc via an outlet plug, a socket, a connector, and the like, and the DC device operates with a DC voltage V2. In FIG. 2, the feedback path of the voltage across the capacitor Cb is omitted.

  In the present embodiment, since the AC-DC conversion unit 2 and the DC-DC conversion unit 3 are integrally configured, one filter unit 1 provided in the previous stage of the AC-DC conversion unit 2 is replaced with the AC-DC conversion unit 2. And the DC-DC converter 3 can be used as noise countermeasures. Further, the drive control of the switching elements Q1 to Q4 included in the AC-DC conversion unit 2 and the drive control of the switching elements Q5 to Q12 included in the DC-DC conversion unit 3 can be combined with one switching control unit 4. Furthermore, the AC-DC converter 2 and the DC-DC converter 3 can also be used as an overvoltage protection circuit (not shown) and a filter provided in the output stage. As described above, the AC-DC conversion unit 2 and the DC-DC conversion unit 3 are integrally configured, so that each unit such as a filter unit, a switching control unit, and a protection circuit can be used together. Cost reduction and simplification of the drive control circuit of the switching element can be achieved.

  Next, the DC voltage V2 is also supplied to the DC circuit Wdc from a distributed power source (not shown) configured by a solar battery or the like, and surplus power is accumulated in the secondary battery E1. Charging / discharging of the secondary battery E1 is controlled by the charge / discharge control circuit 5, and the electric power stored in the secondary battery E1 is released to the DC circuit Vdc as necessary. The AC-DC conversion unit 2 and the DC-DC conversion unit 3 are configured to be capable of bi-directional power conversion. The DC-DC conversion unit 3 reversely converts the DC voltage V2 into the DC voltage V1, and the AC− The DC converter 2 reversely converts the DC voltage V1 into the AC voltage Vac, so that the surplus DC power generated in the DC power distribution system in the house can be supplied to the AC power distribution system side in the house, and further It is also possible to cause a reverse power flow to the AC power supply AC side via the system device 100. The grid interconnection device 100 is inserted between the commercial power supply AC and the AC power line Wac, and switches between grid interconnection and grid separation between the power conversion device (AC-D conversion unit 2) and the commercial power supply AC. Therefore, it has a grid connection protection function for detecting the frequency fluctuation or voltage fluctuation of the commercial power supply AC, or a power failure, and disconnecting the power converter from the commercial power supply AC.

  Hereinafter, the operation at the time of this reverse conversion will be described. First, the switching control unit 4 causes the secondary winding N2 to generate an alternating voltage by alternately turning on and off the switching elements Q9 and Q12 and the switching elements Q10 and Q11 in the DC-DC conversion unit 3 to generate the primary voltage. An alternating voltage is induced in the winding N1. The switching control unit 4 maintains the switching elements Q5 to Q8 in the OFF state, and the alternating voltage induced in the primary winding N1 is full-wave rectified by the diodes D5 to D8 and generates a DC voltage V1 across the capacitor Ca. . The switching control unit 4 feeds back the voltage across the capacitor Ca and controls the on / off driving of the switching elements Q9 to Q12 so that the DC voltage V1 = DC300V. In this way, the DC-DC converter 3 boosts the DC voltage V2 (DC48V) to the DC voltage V1 (DC300V) (third operation). In FIG. 2, the feedback path of the voltage across the capacitor Ca is omitted.

  Next, the switching control unit 4 feeds back the output voltage on the AC side in the AC-DC conversion unit 2 and turns the switching elements Q1 and Q4 and the switching elements Q2 and Q3 alternately on and off. The voltage V1 is inversely converted into an AC voltage Vac of 100 V / 200 V and 50/60 Hz, and AC power is supplied to the AC circuit Wac (fourth operation). In FIG. 2, the AC voltage feedback path is omitted.

  Thus, the AC-DC converter 2 can bidirectionally convert the AC voltage Vac-DC voltage V1 and the DC-DC converter 3 can bidirectionally convert the DC voltage V1-DC voltage V2. In addition, it is not necessary to provide a separate configuration for reverse conversion from the DC power distribution system to the AC power distribution system, and both AC-DC conversion means (AC100V / 200V → DC48V) and DC-AC conversion means (DC48V → AC100V / 200V) are used. Thus, the configuration can be simplified and the cost can be reduced.

  In addition, although DC voltage V2 illustrated DC48V, other voltages, such as DC24V and DC12V, may be sufficient.

(Embodiment 2)
In the present embodiment, the switching elements Q1 to Q4 and the diodes D1 to D4 of the AC-DC converter 2 of the first embodiment are configured by bidirectional switches, and the configuration is shown in FIG. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

  The bidirectional switch is a switch capable of supplying current in both directions, and is turned on / off by a control input. This bidirectional switch is, for example, a reverse connection of a pair of IGBTs, and each IGBT is individually turned on / off for each energization direction by the switching control unit 4. Furthermore, since it has a reverse breakdown voltage characteristic, parallel connection of diodes for preventing reverse breakdown voltage is unnecessary, and the configuration can be simplified and the cost can be reduced. Further, since the MOSFET body diode is not used as in the first embodiment, loss generation during rectification is reduced, and high efficiency can be achieved. In the present embodiment, the switches are referred to as bidirectional switches Q1 to Q4.

  First, an operation in which the AC-DC converter 2 converts the AC voltage Vac to the DC voltage V1 will be described. When the AC voltage Vac is a positive voltage, the switching control unit 4 maintains the bidirectional switches Q2 and Q3 [X1 direction: off state, X2 direction: on state] and bidirectional switch Q1 [both in the X1 and X2 directions]. Then, the drive control is performed to the bidirectional switch Q4 [X1 direction: ON / OFF repeated, X2 direction: OFF state]. When the bidirectional switch Q4 is turned on in the X1 direction, current flows through the inductors L11 and L12 through the path of the AC power supply AC → the inductor L11 → the bidirectional switch Q4 → the bidirectional switch Q2 → the inductor L12 → the AC power supply AC. Energy is stored in L11 and L12. When the X1 direction of the bidirectional switch Q4 is turned off, the energy accumulated in the inductors L11 and L12 is released through the bidirectional switch Q3, and charges the capacitor Ca. Thus, by repeatedly turning on and off the bidirectional switch Q4 in the X1 direction when the AC voltage Vac is a positive voltage, the voltage across the capacitor Ca rectifies the AC voltage Vac with the bidirectional switches Q2 and Q3. The voltage is boosted from the rectified voltage.

  Next, when the AC voltage Vac is a negative voltage, the switching control unit 4 switches the bidirectional switches Q1 and Q4 [X1 direction: off state, X2 direction: on state] and bidirectional switch Q3 [X1 and X2 direction both off state] , And drive control is performed to the bidirectional switch Q2 [X1 direction: ON / OFF repeated, X2 direction: OFF state]. When the bidirectional switch Q2 is turned on in the X1 direction, current flows through the inductors L11 and L12 through the path of the AC power supply AC → inductor L12 → bidirectional switch Q2 → bidirectional switch Q4 → inductor L11 → AC power supply AC. Energy is stored in L12. When the X1 direction of the bidirectional switch Q2 is turned off, the energy accumulated in the inductors L11 and L12 is released through the bidirectional switch Q1 to charge the capacitor Ca. Thus, when the AC voltage Vac is a negative voltage, the bidirectional switch Q2 is repeatedly turned on and off in the X1 direction, so that the DC voltage V1 generated at both ends of the capacitor Ca is changed to the AC voltage Vac by the bidirectional switch Q1. , Q4, a value boosted from the rectified voltage rectified.

  Thus, the switching control unit 4 feeds back the voltage across the capacitor Ca and controls the on / off driving of the bidirectional switches Q1 to Q4 so that the DC voltage V1 = DC300V. In FIG. 3, the feedback path of the voltage across the capacitor Ca is omitted.

  Next, the operation of the AC-DC converter 2 when the power conversion device performs reverse conversion will be described. First, the switching control unit 4 alternately turns on and off the X1 directions of the bidirectional switches Q1 and Q4 and the bidirectional switch elements Q2 and Q3 with the bidirectional switches Q1 to Q4 turned on in the X2 direction. As a result, the DC voltage V1 is inversely converted to an AC voltage Vac of 100 V / 200 V and 50/60 Hz, and AC power is supplied to the AC circuit Wac.

  By using the bidirectional switches Q1 to Q4 in this way, loss during rectification is reduced and efficiency can be improved as compared to the first embodiment in which MOSFET body diodes D1 to D4 are used in the rectifier circuit.

(Embodiment 3)
In the present embodiment, the filter unit 1 of the first or second embodiment is configured as shown in FIG. Other configurations are the same as those in the first or second embodiment, and a description thereof will be omitted.

  First, the AC power reversely converted via the DC-DC converter 3 and the AC-DC converter 2 is likely to flow to the AC power supply AC side having a small output impedance, and the AC power converted from the reverse conversion is used as a home AC distribution system. It was difficult to consume. Therefore, in the present embodiment, the impedance of the filter unit 1 is increased at the time of reverse conversion, and the reverse converted AC power is supplied to the home AC device Ka connected to the power supply path drawn from the filter unit 1. The reverse power flow flowing to the AC power source AC side is reduced, and the reverse-converted power is efficiently consumed by the AC distribution system in the house.

The filter unit 1 of the present embodiment is provided on the AC side of the AC-DC conversion unit 2, and is connected in series to the AC circuit Wac between the capacitors C11 and C12 connected between the AC circuit Wac and the capacitors C11 and C12. The inductors L11 and L12 and the inductors L21 and L22 connected in series to the AC power circuit Wac on the commercial power supply AC side are connected to the AC - DC converter 2 through the filter unit 1. . Furthermore, a residential AC device Kac is connected to an AC circuit W1 derived from both ends of a capacitor C11 provided on the AC-DC converter 2 side of the inductors L21 and L22 (impedance elements).

  The inductor L22 is configured by a mag-amplifier (saturable reactor), and when a direct current is passed through the control winding Na, the iron core is saturated and the impedance is lowered. In the present embodiment, both ends of the control winding Na are connected to the variable DC power source Ea, and the impedance control unit 11 adjusts the DC voltage of the variable DC power source Ea, so that the impedance of the inductor L22 is variably controlled.

  First, when the power converter performs an AC-DC conversion operation and the AC-DC conversion unit 2 converts the AC voltage Vac to the DC voltage V1, the impedance control unit 11 increases the DC voltage of the variable DC power source Ea. Thus, the impedance of the inductor L22 is lowered, and the input efficiency of the AC power supplied to the AC-DC converter 2 is increased.

  On the other hand, when the power converter performs an inverse conversion operation and the AC-DC converter 2 reversely converts the DC voltage V1 to the AC voltage Vac, the impedance controller 11 reduces the DC voltage of the variable DC power source Ea. (For example, 0 V), the impedance of the inductor L22 is increased. That is, the impedance with respect to the AC power flowing from the AC-DC converter 2 to the AC power supply AC is increased. Therefore, it becomes difficult to supply the reversely converted power to the AC power source AC, and the reversely converted power is efficiently supplied to the AC device Kac of the house connected to the AC circuit W1 derived from both ends of the capacitor C11 of the filter unit 1. Can be supplied well. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system.

  Further, when the AC-DC conversion unit 2 performs the reverse conversion operation, the increased impedance of the inductor L22 is set to a value that allows the AC power from the AC power source AC to pass to some extent, and the house connected to the AC circuit W1. Can be supplied by mixing the reverse conversion power from the AC-DC conversion unit 2 and the AC power supplied from the AC power source AC.

(Embodiment 4)
In the present embodiment, the filter unit 1 of the first or second embodiment is configured as shown in FIG. Other configurations are the same as those in the first or second embodiment, and a description thereof will be omitted.

  First, the AC power reversely converted via the DC-DC converter 3 and the AC-DC converter 2 is likely to flow to the AC power supply AC side having a small output impedance, and the AC power converted from the reverse conversion is used as a home AC distribution system. It was difficult to consume. Therefore, in the present embodiment, during reverse conversion, the electric path from the filter unit 1 to the AC power source AC is interrupted, and the reverse-converted AC power is supplied to the AC device Ka of the house connected to the power supply path drawn from the filter unit 1. By supplying the power, the reverse power flow flowing to the AC power source AC side is cut off, and the reverse-converted power is efficiently consumed by the AC power distribution system in the house.

  The filter unit 1 of the present embodiment is provided on the AC side of the AC-DC conversion unit 2, and is connected in series to the AC circuit Wac between the capacitors C11 and C12 connected between the AC circuit Wac and the capacitors C11 and C12. Inductors L11 and L12. A relay contact 13 is connected in series to the AC electric circuit Wac, and the relay contact 13 is driven on and off by the relay drive unit 12. Furthermore, a residential AC device Kac is connected to the AC circuit W1 derived from both ends of the capacitor C11 provided on the AC-DC converter 2 side of the relay contact 13.

  First, when the power conversion device performs an AC-DC conversion operation and the AC-DC conversion unit 2 converts the AC voltage Vac to the DC voltage V1, the relay driving unit 12 turns on the relay contact 13, and the AC-DC conversion operation is performed. The converter 2 is supplied with AC power from the AC power supply AC.

  On the other hand, when the power conversion device performs the reverse conversion operation and the AC-DC conversion unit 2 reversely converts the DC voltage V1 to the AC voltage Vac, the relay driving unit 12 turns off the relay contact 13 to perform reverse conversion. The electric path from the filter unit 1 to the AC power supply AC is interrupted. Therefore, the circuit of the reversely converted power reaching the AC power source AC is interrupted, and the reversely converted AC power is supplied to the AC device Kac of the house connected to the AC circuit W1 derived from both ends of the capacitor C11 of the filter unit 1. It can be supplied efficiently. That is, it becomes possible to complete the supply and consumption of the reversely converted power in the residential power distribution system.

(Embodiment 5)
In the first to fourth embodiments, the AC-DC converter 2 generally generates and reverse-converts the 50/60 Hz AC voltage Vac when the DC voltage V1 is reversely converted to the AC voltage Vac. When the AC-DC converter 2 reversely converts the DC voltage V1 to the AC voltage Vac by the PWM control method, the waveform of the 60 Hz AC voltage output from the AC-DC converter 2 is shown in FIG. The voltage waveform across the capacitor C1 of the filter unit 1 is shown in FIG.

  However, the AC-DC converter 2 may generate and reverse-convert an AC voltage Vac having a high frequency of about 480 Hz, for example. The waveform of the AC voltage of 480 Hz output from the AC-DC conversion unit 2 at this time is shown in FIG. 5C, and the voltage waveform across the capacitor C1 of the filter unit 1 is shown in FIG.

  When the frequency of the inversely converted AC power is increased in this way, the impedances of the inductors L11 and L12 of the filter unit 1 increase, and the inversely converted power hardly flows to the AC power source AC side, and the capacitor C11 of the filter unit 1 It is possible to more efficiently supply the reverse-converted AC power to the AC device Kac of the house connected to the AC circuit W1 derived from both ends of the AC.

DESCRIPTION OF SYMBOLS 1 Filter part 2 AC-DC conversion part 3 DC-DC conversion part 11 Impedance control part Na Control coil | winding L11, L12 Inductor L21, L22 Inductor AC AC power supply W1 AC electric circuit Kac AC apparatus

Claims (3)

A rectifying unit that converts an AC voltage from an AC power source into a first DC voltage is provided, and an AC voltage is converted into a first DC voltage by turning on and off a switching element that constitutes the rectifying unit. An AC-DC converter configured to be switchable between a first operation to output and a second operation to reversely convert the first DC voltage to an AC voltage;
DC converter means for stepping down the first DC voltage to the second DC voltage is provided, and the first DC voltage is converted to the second DC voltage by turning on and off the switching elements constituting the DC converter means. A DC-DC converter configured to be switchable between a third operation for converting to a first direct current voltage and a fourth operation for converting the second direct current voltage back to the first direct current voltage and outputting,
A filter unit including an inductor interposed between the AC power source and the AC-DC conversion unit,
The AC-DC converter and the DC-DC converter are integrally provided in the same housing,
The AC-DC conversion unit turns on / off a switching element that constitutes the rectifying unit, stores and discharges energy in the inductor of the filter unit, and performs a boosting operation, thereby converting an AC voltage into a first DC voltage. Converted to
The DC-DC converter includes a transformer having a pair of coils that are magnetically coupled to each other between a first DC voltage side and a second DC voltage side, and one of the pair of coils is disposed on one coil. Is a series connection of a capacitor and an inductor,
An AC device is connected via an electric circuit derived from the AC-DC conversion unit side from the impedance element in the filter unit, and the impedance of the filter unit is determined when the AC-DC conversion unit performs the second operation. Increased when the AC-DC converter performs the first operation;
The switching element of the AC-DC conversion unit is a bidirectional switch.   The filter unit includes the impedance element whose impedance is variably configured, and an impedance control unit that controls the impedance of the impedance element. The impedance control unit is configured such that the AC-DC conversion unit performs the second operation. The power converter according to claim 1, wherein an impedance when performing the first operation is set larger than an impedance when performing the first operation.   When the second operation is performed, the AC-DC converter back-converts the first DC voltage into an AC voltage having a frequency higher than the frequency of the AC power supply, and outputs the AC voltage from the inductor in the filter unit. The power converter according to claim 1, wherein the AC device is connected through an electric circuit derived from a DC converter.

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