JP6794875B2 - Power converter - Google Patents

Description

The present invention relates to a power conversion device, and more particularly to a device including two magnetically coupled switching circuits.

Electric vehicles such as hybrid vehicles and electric vehicles are widely used. The electric vehicle is equipped with a battery for supplying electric power to the drive motor. In a hybrid vehicle, the battery is charged by the driving force of the engine and the electric power generated by regenerative braking. Further, in an electric vehicle having a plug-in function, the battery is charged by the electric power supplied from the commercial power source. Electric vehicles are equipped with a power converter to charge the battery. The power converter converts the voltage input for charging the battery into an appropriate voltage and applies it to the battery.

The following Patent Documents 1 and 2 show a power conversion device in which two switching circuits are magnetically coupled by windings of each circuit and power is transmitted between the two switching circuits. Further, Non-Patent Document 1 describes a Cuk circuit as a circuit related to the present invention. The Cuk circuit includes a first loop 10 and a second loop 12 as shown in FIG. The first loop 10 includes power supply side capacitor _{C V,} the first winding _{L 1,} and the power source side switching elements _{S A,} the second loop 12, the load-side capacitor _{C L,} the load-side switching elements _{S B,} and the Two windings L ₂ are included. The first winding L ₁ and the second winding L ₂ are formed by a conducting wire wound around a core Fp formed of a magnetic material. Cuk circuit further includes a one end of the power supply side switching elements S _A, it comprises a connected intermediate capacitor C _t between one end of the load side switching element S _B, the other end and the power source side switching elements S _A The other end of the load-side switching element SB is commonly connected. _A DC power supply EA is connected to both ends of the power supply side capacitor _CV , and a load _RL is connected to both ends of the load side capacitor C _L.

Power source side switching elements S _A is turned on, the load-side switching element S _B is that turned off, current flows Ia and Ib. Current Ia from the parallel-connected DC power source E _A and the power source side capacitor C _V through the first winding L ₁ and the power source side switching elements SA, returning to the DC power source E _A and the power source side capacitor C _V, current Ib from intermediate capacitor _{C t,} the power supply side switching elements _{S a,} through the parallel connected load capacitor _{C L} and the load _{R L,} the flow returns to intermediate capacitor _{C t} through further secondary winding _{L 2.}

Power source side switching elements S _A is turned off, the load-side switching element S _B is that turned on, current flows Ic and current Id. Current Ic is parallel connected DC power source _{E A} and the first winding _{L 1} from the power source side capacitor _{C V,} via intermediate capacitor _{C t} and the load-side switching elements _{S B,} the DC power source _{E A} and the power source side capacitor _{C V} return, current Id, the load-side switching elements _{S B} from the second winding _{L 2,} through the parallel connected load capacitor _{C L} and the load _{R L,} back to the second winding _{L 2.} Power supply side capacitor C _V and the load-side capacitor C _L, respectively, holding the output voltage and the voltage between the terminals of the load R _L of the DC power source E _A.

By the power supply side switching elements S _A and the load-side switching element S _B are alternately turned on and off, and a state in which current flows Ia and Ib, a state in which current flows Ic and Id are formed alternately, the load R from the DC power source E _A Energy is transmitted to _L. By first winding L ₁ and the second winding L ₂ are formed on a common core Fp, magnetic flux interlinking is strengthened in each winding, the power supplied from the DC power source E _A load R _L Becomes larger.

In addition to electric vehicles, electric power converters are also used in general industrial machines, solar cell systems in homes, and private power generation systems.

Japanese Unexamined Patent Publication No. 2011-193713 Japanese Unexamined Patent Publication No. 2006-187147

Web page about "Cuk converter" in English Wikipedia

In a power conversion device as described in Patent Documents 1 and 2 and Non-Patent Document 1, the power transmission efficiency is generally lowered by the heat generated in the winding.

An object of the present invention is to reduce the power loss generated in the winding of the power conversion device.

In a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material, at least one of the first switching circuit and the second switching circuit is provided in the magnetic path. A second loop including a first winding, a first capacitor, and a first switching element, a second winding provided in the magnetic path, a second capacitor, and a second switching element. A loop, a path connecting the first switching element and the first winding, and a third capacitor provided between the path connecting the second switching element and the second winding are provided. The path connecting the first switching element and the first capacitor and the path connecting the second switching element and the second capacitor are commonly connected, and power is input and output from both ends of the third capacitor. It is characterized by being done.

Further, according to the present invention, in a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material, at least one of the first switching circuit and the second switching circuit is the magnetic. A first loop including a first winding, a first capacitor, and a first switching element provided on the path, a second winding provided on the magnetic path, a second capacitor, and a second switching element. A third capacitor provided between a second loop including the above, a path connecting the first switching element and the first winding, and a path connecting the second switching element and the second winding. And a fourth capacitor provided between a path connecting the first winding and the first capacitor and a path connecting the second winding and the second capacitor, the first The path connecting the switching element and the first capacitor and the path connecting the second switching element and the second capacitor are commonly connected, and power is input and output from both ends of the fourth capacitor. It is characterized by that.

Further, according to the present invention, in a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material, each of the first switching circuit and the second switching circuit has the magnetic path. The first winding provided in the magnetic path, the first capacitor, the first loop including the first switching element, the second winding provided in the magnetic path, the second capacitor, and the second switching element. A second loop including the above, a third capacitor provided between a path connecting the first switching element and the first winding, and a path connecting the second switching element and the second winding. The path for connecting the first switching element and the first capacitor and the path for connecting the second switching element and the second capacitor are commonly connected, and the first switching element and the second capacitor are connected in common. The switching elements are alternately turned on and off, and power corresponding to the time difference between the switching timing in the first switching circuit and the switching timing in the second switching circuit is transmitted between the first switching circuit and the second switching circuit. It is characterized by that.

Desirably, in each of the first switching circuit and the second switching circuit, power is input / output from both ends of the third capacitor.

Desirably, each of the first switching circuit and the second switching circuit has a path for connecting the first winding and the first capacitor and a path for connecting the second winding and the second capacitor. A fourth capacitor provided between them is provided, and power is input and output from both ends of the fourth capacitor.

Desirably, power is input and output from both ends of the third capacitor in one of the first switching circuit and the second switching circuit, and the other of the first switching circuit and the second switching circuit is the first. A fourth capacitor provided between a path for connecting the first winding and the first capacitor and a path for connecting the second winding and the second capacitor is provided, and power is supplied from both ends of the fourth capacitor. It is characterized by being input and output.

According to the present invention, it is possible to reduce the power loss generated in the winding provided in the power conversion device.

It is a figure which shows the structure of the power conversion apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the time waveform of the voltage of each winding and the current flowing through each winding. It is a figure which shows the time waveform of the voltage of each winding, the current flowing through each winding, the input current and the output current. It is a figure which shows the current flowing through each element. It is a figure which shows the current flowing through each element. It is a figure which shows the structure of the ripple suppression / power conversion apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure of the ripple suppression / power conversion apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the time waveform of the voltage of each winding, and the current flowing through each winding. It is a figure which shows the time waveform of the voltage of each winding, the current flowing through each winding, the tank current, the input current and the output current. It is a figure which shows the additional ripple current flowing through each element. It is a figure which shows the additional ripple current flowing through each element. It is a figure which shows the structure of the half-bridge switching circuit and the full-bridge switching circuit. It is a figure which shows the structure of a Cook circuit.

FIG. 1 shows the configuration of the power conversion device according to the first embodiment of the present invention. The power conversion device includes a primary circuit 14, a secondary circuit 16, and a core Fp.

The primary circuit 14 includes a first winding _{L 1,} first capacitor _{C 1,} the first switching element _{S 1,} the second winding _{L 2,} the second capacitor _{C 2,} a second switching element _{S 2,} the primary capacitor _{C A} , A first terminal 1 and a second terminal 2 are provided. A field effect transistor, a bipolar transistor, an IGBT (Insulated Gate Bipolar Transistor), or the like may be used for each switching element. The same applies to each switching element described below.

The first winding L ₁ and the first capacitor C ₁ are connected in series. The first switching element S ₁ is connected in parallel to the first winding L ₁ and the first capacitor C ₁ connected in series. A parasitic diode is connected in parallel to the first switching element S ₁ with the side connected to the first winding L ₁ as a cathode.

The second winding L ₂ and the second capacitor C ₂ are connected in series. The second switching element S ₂ is connected in parallel to the second winding L ₂ and the second capacitor C ₂ connected in series. The second switching element S _2, a parasitic diode is connected in parallel side connected second winding to L ₂ as the anode.

One end of the first capacitor C ₁ on the opposite side of the first winding L ₁ side is connected to one end of the second capacitor C ₂ on the opposite side of the second winding L ₂ side.

A primary capacitor C is located between one end of the first winding L ₁ on the opposite side of the first capacitor C ₁ side and one end of the second winding L ₂ on the opposite side of the second capacitor C ₂ side. _A is connected. Across the primary capacitor C _A has a first terminal 1 and the second terminal 2 are connected.

The winding directions of the first winding L ₁ and the second winding L ₂ are opposite to each other. That is, when the induced electromotive force point is attached side as positive in the first winding L ₁ occurs, induced electromotive force point is attached side as positive in the second winding L ₂ occurs To do. Similarly, when the induced electromotive force point is attached side as positive in the second winding L ₂ occurs, the induced electromotive force of the side where the points attached to the first winding L ₁ is positive Occur. In the following description, the voltage between the terminals of each winding is based on the terminal on the side not marked with a dot.

The secondary circuit 16 includes a third winding L ₃ , a third capacitor C ₃ , a third switching element S ₃ , a fourth winding L ₄ , a fourth capacitor C ₄ , a fourth switching element S ₄ , and a secondary capacitor C _B. , A third terminal 3 and a fourth terminal 4 are provided. The secondary circuit 16 has the same configuration as the primary circuit 14.

The third winding L ₃ and the fourth winding L ₄ correspond to the first winding L ₁ and the second winding L ₂ , respectively. The third capacitor C ₃ and the fourth capacitor C ₄ correspond to the first capacitor C ₁ and the second capacitor C ₂ , respectively. The third switching element S ₃ and the fourth switching element S ₄ correspond to the first switching element S ₁ and the second switching element S ₂ , respectively. The secondary capacitor C _B corresponds to the primary capacitor CA _A. The third terminal 3 and the fourth terminal 4 are connected to both ends of the secondary capacitor C _B.

The core Fp is cyclically formed of a magnetic material such as iron or ferrite. The first winding L ₁ , the second winding L ₂ , the third winding L ₃ and the fourth winding L ₄ are formed by a conducting wire wound around the core Fp. The core Fp forms a magnetic path for the magnetic flux generated by each winding. The magnetic flux generated in one winding passes through the core Fp and interlinks with the other winding. When an induced electromotive force is generated in one winding where the pointed side is positive, an induced electromotive force is generated in the other winding where the pointed side is positive. The first winding L ₁ and the second winding L ₂ are magnetically coupled, the first winding L ₁ and the third winding L ₃ are magnetically coupled, and the second winding L ₂ and the fourth winding Since the wire L ₄ is magnetically coupled and the third winding L ₃ and the fourth winding L ₄ are magnetically coupled, no gap is provided in the core Fp.

The first switching element S ₁ and the second switching element S ₂ alternately repeat on / off. That is, when the first switching element S ₁ is on, the second switching element S ₂ is turned off, and when the first switching element S ₁ is off, the second switching element S ₂ is turned on. Similarly, the third switching element S ₃ and the fourth switching element S ₄ alternately repeat on / off.

Here, the DC voltage V _A is applied to the first terminal 1 and the second terminal 2 of the primary circuit 14, the state in which the DC voltage V _B are outputted from the third terminal 3 and the fourth terminal 4 of the secondary circuit 16 described To do. Each capacitor is charged with a constant voltage. For each capacitor, the voltage with the terminal side marked with "+" as the positive electrode is the positive electrode of the charging voltage of each capacitor.

FIG. 2 shows the voltage of each winding when the first switching element S ₁ and the second switching element S ₂ are turned on and off and the third switching element S ₃ and the fourth switching element S ₄ are turned on and off in the same phase. , And the time waveform of the current flowing through each winding is shown. When the switching timings of the primary circuit 14 and the secondary circuit 16 are in phase in this way, the power transmitted between the primary circuit 14 and the secondary circuit 16 is 0.

First winding _{L 1} of the terminal voltage _{V L1} (first winding voltage _{V L1)} of the time waveform, and the second winding _L between the _two terminal voltages _{V L2} (second winding in FIGS. 2 (a) The time waveform of the voltage _VL2 ) is shown. The first coil voltage V _L1 is high voltage H for a period of time, the second switching element S ₂ coincides with the time of the on-time first winding voltage V _L1 is a low voltage L, the first switching element S ₁ coincides with the on time.

When the first switching element S ₁ is turned off and the second switching element S ₂ is turned on, the first capacitor C ₁ and the primary capacitor CA _A are connected in series between the terminals of the first winding L _1. The first winding voltage _VL1 becomes a high voltage H. This high voltage H is a voltage obtained by subtracting the first charging voltage of the capacitor C ₁ from the charging voltage of the primary capacitor C _A. The first switching element S ₁ is turned on, by the second switching element S ₂ is turned off, the first capacitor C ₁ is connected between the first winding L ₁ terminal, a first winding voltage V _L1 Is a low voltage L. The low voltage L is a voltage obtained by inverting the polarity of the first charging voltage of the capacitor C _1.

Similar to the first winding voltage V _L1, the second coil voltage V _L2 is the time high voltage H, the second switching element S ₂ coincides with the time of the ON state, the second winding voltage V _L2 is low voltage L for a period of time, the first switching element S ₁ is coincident with the time of oN.

When the first switching element S ₁ is turned off and the second switching element S ₂ is turned on, the second capacitor C ₂ is connected between the terminals of the second winding L ₁ , and the second winding voltage V _L2 has a high voltage H. This high voltage H is the charging voltage of the second capacitor C ₂ . When the first switching element S ₁ is turned on and the second switching element S ₂ is turned off, the second capacitor C ₂ and the primary capacitor CA _A are connected in series between the terminals of the second winding L ₂ . The second winding voltage _VL2 becomes a low voltage L. The low voltage L, the second charging capacitor C ₂ of the voltage obtained by subtracting the charge voltage of the primary capacitor C _A from the charging voltage (primary capacitor C _A second capacitor C ₂ from those obtained by inverting the polarity of the charging voltage of the The voltage obtained by subtracting the voltage polarity inverted).

Are shown time waveform in the time waveform, and a fourth winding _{L 4} of the terminal voltage _{V L4} of terminal voltage _{V L3} of the third winding _{L 3} in FIG. 2 (b). The third winding voltage V _L3 is time high voltage H, the fourth switching element S ₄ matches the time on, the third winding voltage V _L3 is time low voltage L, the third switching element S ₃ coincides with the on time. Similar to the first winding L ₁ , the high voltage H appearing between the terminals of the third winding L ₃ is a voltage obtained by subtracting the charging voltage of the third capacitor C ₃ from the charging voltage of the secondary capacitor C _B , and is low. voltage L is a voltage obtained by inverting the polarity of the third charging voltage of the capacitor C _3.

Similar to the second coil voltage V _L2, the fourth winding voltage V _L4 is time high voltage H, the fourth switching element S ₄ coincides with the time of the on, fourth winding voltage V _L4 is low voltage L for a period of time, the third switching element S ₃ coincides with the time of oN. Similar to the second winding L ₂ , the high voltage H appearing in the fourth winding L ₄ is the charging voltage of the fourth capacitor C ₄ , and the low voltage L is the charging voltage of the fourth capacitor C ₄ to the secondary capacitor. a voltage obtained by subtracting the charge voltage of C _B.

FIG. 2 (c) shows the exciting currents (i _L1 , i _L2 , i _L3 and i) flowing through the first winding L ₁ , the second winding L ₂ , the third winding L ₃ and the fourth winding L _4. The time waveform of _L4 ) is shown. The exciting current is a current that does not contribute to power transmission. Time waveform of the exciting current flowing through the first winding L ₁ and the second winding L ₂ is represented by a solid line, the table time waveform by the broken lines of the exciting current flowing through the third winding L ₃ and the fourth winding L ₄ Has been done.

FIG. 2 (d), the input current flows from the positive terminal of the primary capacitor _{C A} to the first switching element _{S 1} or the first winding _{L 1 I A.} Time waveform of _IN, and the output current _{I B.} flowing out of the third switching element _{S 3} or the third winding _{L 3} to the positive terminal of the secondary capacitor _{C B} The time waveform of _OUT is shown. Input current I _{A. IN} is the excitation current and the second winding _{L 2} of the excitation current of the first winding _{L 1.} These exciting currents alternately change in inclination polarity as the second switching element S ₂ and the first switching element S ₁ are turned on and off, and increase or decrease with 0 as the median value. Output current IB _{. OUT} is the excitation current and excitation current of the fourth winding _{L 4} of the third winding _{L 3.} The polarity of the inclination of these exciting currents changes alternately as the fourth switching element S ₄ and the third switching element S ₃ are turned on and off, and the excitation current increases or decreases with 0 as the median value.

When the switching timings of the primary circuit 14 and the secondary circuit 16 are the same, the power transmitted between the primary circuit 14 and the secondary circuit 16 is 0.

3 (a) and 3 (b) show the on / off phases of the first switching element S ₁ and the second switching element S ₂ with respect to the on / off phases of the third switching element S ₃ and the fourth switching element S _4. The voltage of each winding when advanced by φ is shown. The phase is defined as the phase angle when one on / off cycle is 2π.

The FIG. 3 (c), the current _{I L1} flowing in such a state to the first winding _{L 1,} current _{I L2} flowing second winding to _{L 2,} the current _{I L3} flowing through the third winding _{L 3,} and , and the current _{I L4} flowing through the fourth winding _{L 4} is shown. As for the polarity of the current of each winding, the current flowing into the terminal on the side with a dot is positive.

When the switching timings of the primary circuit 14 and the secondary circuit 16 are in phase, the power transmitted from the primary side to the secondary side is 0. However, when there is a phase difference between the switching timings of the primary circuit 14 and the secondary circuit 16, power is transmitted from the primary side to the secondary side.

That is, when there is a phase difference switching timing of the switching timing and the secondary side of the primary side, off of the switching element S ₁ and switching element S ₃ is reversed, off of the switching element S ₂ and the switching element S ₄ is reversed There is a period of reverse polarity. The opposite polarity period _{(r 1, r 2, r} 3, ····) in, as shown in FIG. 3 (b), the first winding voltage _{V L1} of the third winding voltage _{V L3} The polarities are reversed, the polarities of the second winding voltage _VL2 and the fourth winding voltage _VL4 are reversed, and the change in the current flowing through each winding becomes large.

Then, the same polarity period (t ₁ , t ₂ , t ₃ , ...) The on / off of the switching element S ₁ and the switching element S ₃ is the same, and the on / off of the switching element S ₂ and the switching element S ₄ is the same. In (), a trapezoidal current that changes slowly flows through each winding. In this same polarity period, the polarities of the first winding voltage _VL1 and the third winding voltage _VL3 become the same, and the polarities of the second winding voltage _VL2 and the fourth winding voltage _VL4 become the same and change. A gentle trapezoidal current flows through each winding, and the current flowing through each winding holds the current energy in each winding.

In the same polarity period, the electric power determined by the product of the first winding voltages V _L1 and the primary winding L ₁ of the trapezoidal current, determined by the product of the second winding voltage V _L2 and second winding L ₂ of the trapezoidal current The electric power combined with the electric power is transmitted from the primary side to the secondary side. Power transmitted from the primary side to the secondary side, a power determined by the product of the trapezoidal current of the third winding voltage V _L3 and the third winding L _3, fourth winding voltage V _L4 and fourth winding L ₄ It is also represented by the combined power with the power determined by the product of the trapezoidal currents.

That is, in the same polarity period, the electric power determined by the product of the trapezoidal current of the first winding voltages V _L1 and the first coil _L1, by the product of the second winding trapezoidal current of the voltage V _L2 and second winding L ₂ The electric power including the determined electric power is input from the first terminal 1 and the second terminal 2. Further, in the same polarity period, the electric power determined by the product of the trapezoidal current of the third winding voltage V _L3 and the third winding L _3, the product of the trapezoidal current of the fourth winding voltage V _L4 and fourth winding L ₄ The electric power including the electric power determined by is output from the third terminal 3 and the fourth terminal 4.

As the phase difference φ between the switching timing on the primary side and the switching timing on the secondary side is larger in the range of 0 or more and π or less, each inverse polarity period becomes longer and the absolute value of the trapezoidal current becomes larger. Therefore, the larger the phase difference φ is within the range of 0 or more and π or less, the larger the power transmitted from the primary side to the secondary side.

FIG. 4 (a) shows the current flowing through the windings in the opposite polarity period r _1. The winding current I _L1 flowing through the first winding L ₁ passes through the first winding L ₁ to the first capacitor C ₁ , the second switching element S ₂ , and the primary capacitor CA _A , and the first winding L _It flows through the path returning to ₁ , and the direction of this flow is positive. Winding current _{I L1} in reversed polarity period _{r 1,} the input current _{I A.} It becomes _IN . Winding current _{I L2} flowing in the second winding _{L 2} flows through the path back from the secondary winding _{L 2} through the second capacitor _{C 2} and the second switching element _{S 2} to the second winding _{L 2,} the The direction of the flow is positive. The winding current _{IL 3} flowing through the third winding L ₃ flows through the third capacitor C ₃ and the third switching element S ₃ and returns to the third winding L ₃ , and the direction of this flow is positive. .. The winding current I _L4 flowing through the fourth winding L ₄ passes through the fourth winding L ₄ to the fourth capacitor C ₄ , the third switching element S ₃ , and the secondary capacitor C _B , and the fourth winding L ₄ It flows through the path back to, and the direction of this flow is positive. Winding current _{I L4} in the opposite polarity period _{r 1} is the output current _{I B.} It becomes _OUT .

FIG. 4 (b) shows the current flowing through the windings in the same polarity period t _1. Path first winding currents _{I L1} and second winding current _{I L2} flows is similar to the reverse polarity period _{r 1.} Winding current _{I L1} in the same polarity period _{t 1,} the input current _{I A.} It becomes _IN . Winding current _{I L3} flowing through the third winding _{L 3} from the third winding _{L 3,} the third capacitor _{C 3,} the fourth switching element _{S 4,} the third winding _{L 3} through the secondary capacitor _{C B} It flows through the path back to, and the direction of this flow is positive. Obtained by inverting the polarity of the winding current I _L3 in the same polarity period t ₁ is the output current I _B. It becomes _OUT . Winding current _{I L4} flowing through the fourth winding _{L 4} are flow a path back from the fourth winding _{L 4} through a fourth capacitor _{C 4} and the fourth switching element _{S 4} to the fourth winding _{L 4,} the The direction of the flow is positive.

In FIGS. 5 (a) is shown the current flowing through the windings in the opposite polarity period r _2. First winding current I _L1 from the first winding L ₁ through the first capacitor C ₁ and the first switching element S ₁ path flow back to the first winding L _1, the direction of the flow the positive and To do. The second winding current _{IL 2} flows through the second capacitor C ₂ , the first switching element S ₁ , and the primary capacitor CA _A and returns to the second winding L ₂ , and the direction of this flow is positive. To do. Obtained by inverting the polarity of the winding current I _L2 in the opposite polarity period r ₂ is the input current I _A. It becomes _IN . Path third winding currents _{I L3} and the fourth winding current _{I L4} flows is similar to the same polarity period _{t 1.}

In FIG. 5 (b) is shown the current flowing through the windings in the same polarity period t _2. Path first winding currents _{I L1} and second winding current _{I L2} flows is the same opposite polarity period _{r 2.} Path third winding currents _{I L3} and the fourth winding current _{I L4} flows is the same opposite polarity period _{r 1.}

As described above, the power conversion device according to the present embodiment has a primary circuit 14 (first switching circuit) and a secondary circuit 16 (second switching circuit) that are magnetically coupled by a core Fp as a magnetic path formed of a magnetic material. The power is transmitted between the primary circuit 14 and the secondary circuit 16.

The primary circuit 14 includes a first loop including a first winding L ₁ provided on the core Fp, a first capacitor C ₁ , and a first switching element S ₁ , and a second winding L ₂ provided on the core Fp. , The second loop including the second capacitor C ₂ and the second switching element S ₂ , the path connecting the first switching element S ₁ and the first winding L ₁ , and the second switching element S ₁ and the second volume. and a primary capacitor C _{a (third} capacitor) provided between the path connecting the line L _2. The path connecting the first switching element S ₁ and the first capacitor C ₁ and the path connecting the second switching element S ₂ and the second capacitor C ₂ are commonly connected, and the first switching element S ₁ and the path connecting the second capacitor C ₂ are connected in common. The second switching element S ₂ turns on and off alternately.

The secondary circuit 16 includes a third loop including a third winding L ₃ provided on the core Fp, a third capacitor C ₃ , and a third switching element S ₃ , and a fourth winding L ₄ provided on the core Fp. , The fourth loop including the fourth capacitor C ₄ and the fourth switching element S ₄ , the path connecting the third switching element S ₃ and the third winding L ₃ , and the fourth switching element S ₄ and the fourth volume. It is provided with a secondary capacitor C _B provided between the path connecting the wire L ₄ and the line L ₄ . The path connecting the third switching element S ₃ and the third capacitor C ₃ and the path connecting the fourth switching element S ₄ and the fourth capacitor C ₄ are commonly connected, and the third switching element S ₃ and the path connecting the fourth capacitor C ₄ are connected in common. The fourth switching element S ₄ turns on and off alternately.

The power corresponding to the phase difference (time difference) between the switching timing of the first switching element S ₁ and the second switching element S _{2 and} the switching timing of the third switching element S ₃ and the fourth switching element S ₄ is the primary circuit 14 And is transmitted between the secondary circuits 16.

In the power conversion device according to the present embodiment, the first winding L ₁ and the second winding L ₂ is provided on the primary side, and the third winding L ₃ and the fourth winding L ₄ is provided on the secondary side There is. In this way, when power is transmitted with two pairs of windings, the transmission power is higher than when power is transmitted with one pair of windings. However, the number of turns on the primary side of the pair of windings is the total number of turns of the first winding L ₁ and the number of turns of the second winding L ₂ , and the number of turns on the secondary side is the number of turns of the third winding L ₃ and a comparison with conditions that are the fourth winding turns in conjunction with the number of turns of L _4. Therefore, even if the trapezoidal current flowing through each winding is reduced during the same polarity period, sufficient power is transmitted and the loss based on the current flowing through each winding is reduced.

Further, one end of the second switching element S ₂ is connected to the second terminal 2. Therefore, when the second terminal 2 is connected to the ground conductor, one end of the second switching element S ₂ is also connected to the ground conductor, facilitating the design of the circuit that controls the second switching element S ₂ . For example, when the second switching element S ₁ is a field transistor, the circuit configuration for obtaining a reference of the gate potential for controlling the on / off of the field transistor becomes easy. Similarly, one end of the fourth switching element S ₄ is connected to the fourth terminal 4. Therefore, when the fourth terminal 4 is connected to the ground conductor, one end of the fourth switching element S ₄ is also connected to the ground conductor, facilitating the design of the circuit for controlling the fourth switching element S 4.

FIG. 6 shows the configuration of the ripple suppression / power conversion device according to the second embodiment of the present invention. The same components as those shown in FIG. 1 are designated by the same reference numerals to simplify the description. It includes a ripple suppression / primary circuit 26, a ripple suppression / secondary circuit 28, and a core Fp.

Ripple suppression / primary circuit 26 includes a first winding L ₁ , a first capacitor C ₁ , a first switching element S ₁ , a second winding L ₂ , a second capacitor C ₂ , a second switching element S ₂ , and a primary circuit. capacitor _{C a,} the primary additional capacitor _{C C,} and a fifth terminal 5 and the sixth terminal 6.

The ripple suppression / secondary circuit 28 includes a third winding L ₃ , a third capacitor C ₃ , a third switching element S ₃ , a fourth winding L ₄ , a fourth capacitor C ₄ , a fourth switching element S ₄ , and a secondary circuit. It is provided with a capacitor C _B , a secondary / additional capacitor C _D , a seventh terminal 7 and an eighth terminal 8.

The ripple suppression / power conversion device is a modification of the power conversion device shown in FIG. FIG. 7 is a diagram showing a deformation process. That is, the ripple suppression / power conversion device is guided through the following transformation process. (I) A primary additional capacitor _CC is connected between the connection point between the first winding L ₁ and the first capacitor C ₁ and the connection point between the second winding L ₂ and the second capacitor C ₂ . (Ii) A secondary / additional capacitor C _D is connected between the connection point between the third winding L ₃ and the third capacitor C ₃ and the connection point between the fourth winding L ₄ and the fourth capacitor C ₄ . And (iii) connecting the fifth terminal 5 and the sixth terminal 6 at both ends of the primary additional capacitor _{C C.} (Iv) connecting the seventh terminal 7 and the eighth terminal 8 across the secondary additional capacitor _{C D.} (V) Each winding is provided on the core Fp so that the fifth terminal 5 and the sixth terminal 6 are located on the left side and the seventh terminal 7 and the eighth terminal 8 are located on the right side.

The FIGS. 8 (a) and 8 (b), and on-off of the first switching element _{S 1} and second switching element _{S 2,} lines in the third switching element _{S 3} and the fourth switching element _{S 4} on-off and is in phase The voltage of each winding when it is used, and the time waveform of the current flowing through each winding are shown. When the switching timings of the ripple suppression / primary circuit 26 and the ripple suppression / secondary circuit 28 are in phase in this way, the power transmitted between the ripple suppression / primary circuit 26 and the ripple suppression / secondary circuit 28 is 0. is there.

In the ripple suppression / power conversion device shown in FIG. 6, the voltage reference terminal of each winding is opposite to the power conversion device shown in FIG. Therefore, the first winding voltages _{V L1} and second winding voltage _{V L2} shown in FIG. 8 (a), first winding voltage VL ₁ and second winding voltage _{V L2} shown in FIG. 2 (a) It has the opposite polarity to. Similarly, the third winding voltage _VL3 and the third winding voltage _VL3 shown in FIG. 8B are the third winding voltage _VL3 and the fourth winding voltage V shown in FIG. 2B. _It has the opposite polarity to _L4 .

The reverse winding direction of each winding does not affect the self-inductance of each winding. Therefore, the exciting current flowing through each winding shown in FIG. 8 (c) is the same as the exciting current shown in FIG. 2 (c).

In FIG. 8 (d), the input current _I flows from the positive terminal of the primary additional capacitor _{C C} in the first winding _{L 1} and the first capacitor _{C 1 A.} Time waveform of _IN, and the output current _{I B.} flowing out of the third winding _{L 3} and the third capacitor _{C 3} to the positive terminal of the secondary additional capacitor _{C D} The time waveform of _OUT is shown. As described later, by the current flowing through the primary add capacitors C _C and secondary additional capacitor C _D, the input current IA. IN and output current IB _. The ripple of _OUT is suppressed, and the input current IA _{. IN} and output current IB _{. OUT} is constant at 0.

9 (a) and 9 (b) show the on / off phases of the first switching element S ₁ and the second switching element S ₂ with respect to the on / off phases of the third switching element S ₃ and the fourth switching element S _4. The voltage of each winding when advanced by φ is shown.

FIG. 9 (c) shows the first winding current _IL1 , the second winding current _IL2 , the third winding current _IL3 , and the fourth winding current _IL4 in such a state. There is. As for the polarity of the current of each winding, the current flowing out from the terminal on the side with a dot is positive.

If the switching timing of the switching timing and the secondary side of the primary side there is a phase difference, off of the switching element S ₁ and switching element S ₃ is reversed, off of the switching element S ₂ and the switching element S ₄ are opposite A reverse polarity period occurs. In this reverse polarity period (p ₁ , p ₂ , p ₃ , ...), As shown in FIG. 9, the polarities of the first winding voltage VL ₁ and the third winding voltage VL ₃ are opposite. Therefore, the polarities of the second winding voltage _VL2 and the fourth winding voltage _VL4 are reversed, and the change in the current flowing through each winding becomes large.

Then, the same polarity period (q ₁ , q ₂ , q ₃ , ...) The on / off of the switching element S ₁ and the switching element S ₃ is the same, and the on / off of the switching element S ₂ and the switching element S ₄ is the same. In (), a trapezoidal current that changes slowly flows through each winding. In this same polarity period, a first winding voltage V _L1 as indicated polarity of the third winding voltage V _L3 is identical to FIG. 9, the second coil voltage V _L2 and the fourth winding voltage V A trapezoidal current with the same polarity of _{L4 and} a gradual change flows in each winding, and energy is held in each winding by the current flowing in each winding.

Ripple suppression-power converter, by the action of the primary additional capacitors C _C and secondary additional capacitor C _D, the first winding currents I _L1 and the fourth winding current I _L4 is offset in the negative direction, Volume 2 line current _{I L2} and third winding current _{I L3} is offset in the positive direction.

In FIG. 9 (d), the primary capacitor _C tank circuit flows from the positive terminal of the _{A I A.} Tank current _{I B.} flowing to the positive terminal of the _TANK and secondary capacitors _{C B TANK} is shown. Tank current I _{A. The} operation of the _TANK flowing is the input current I _A. in the power converter shown in FIG. _It is the same as the operation in which _IN flows, and the tank current IB _{. The} operation of the _TANK flowing is the output current _IB shown in FIG. _It is the same as the operation in which _OUT flows. That is, the tank current I _A. shown in FIG. 9 (d) _{. TANK} and _{IB . The TANKs} are the input currents I _A. shown in FIG. 3 (d), respectively. _IN and output current I _A. It corresponds to _OUT .

In FIG. _9E , the input current IA _{. IN} and output current IB _{. OUT} is shown. As described below, the ripple current by the primary additional capacitors C _C and secondary additional capacitor C _D is suppressed, the input current I _{A. IN} and output current IB _{. OUT} is constant.

10 and 11, the ripple current flowing through the primary add capacitors C _C and secondary additional capacitor C _D is shown. These figures focus only on the ripple current that flows when the primary / additional capacitor _CC and the secondary additional capacitor C _D are connected to the power converter shown in FIG. Therefore, the currents corresponding to the currents shown in FIGS. 4 and 5, respectively, flow in the elements shown in FIGS. 10 and 11, respectively, but for the sake of simplicity, these currents flow. Is omitted.

In FIG. 10 (a), first additional ripple current 30 and the second additional ripple current 32 flowing in the opposite polarity period p ₁ to the primary add capacitor C _C is shown. The first additional ripple current 30, the primary additional capacitor _{C C} from the first winding _{L 1,} the second capacitor _{C 2,} a second switching element _{S 2,} and the primary capacitor _{C A} stream, the first winding _{L 1} Return to. The second additional ripple current 32 flows from the second winding L ₂ through the primary additional capacitor _CC , the first capacitor C ₁ , and the second switching element S ₂ , and returns to the second winding L ₂ .

Further, in FIG. 10 (a), the third additional ripple current 34 and the fourth additional ripple current 36 flowing in the opposite polarity period p ₁ to the secondary additional capacitor C _D is shown. The third additional ripple current 34, the third winding _{L 3} from the third switching element _{S 3,} a fourth capacitor _{C 4,} and flows through the secondary additional capacitor _{C D,} returns to the third winding _{L 3.} The fourth additional ripple current 36 flows from the fourth winding L ₄ through the secondary capacitor C _B , the third switching element S ₃ , the third capacitor C ₃ , and the secondary additional capacitor C _D, and flows through the fourth winding L ₄ Return to.

FIG. 10 (b) first adding the ripple current 30 and the second additional ripple current 32 flowing through the same polarity period q ₁ to the primary add capacitor C _C is shown. Path first adds ripple current 30 and the second additional ripple current 32 flows is the same as the opposite polarity period p _1.

Further, in FIG. 10 (b) third additional ripple current 34 and the fourth additional ripple current 36 flowing through the same polarity period q ₁ to the secondary additional capacitor C _D is shown. The third additional ripple current 34 flows from the third winding L ₃ through the secondary additional capacitor C _D , the fourth capacitor C ₄ , the fourth switching element S ₄ , and the secondary capacitor C _B, and flows through the third winding L ₃ Return to. The fourth additional ripple current 36 returns from the fourth winding _{L 4} secondary additional capacitor _{C D,} the fourth winding _{L 4} and the third capacitor _{C 3,} and a fourth switching element _{S 4} stream.

FIG. 11 (a), first additional ripple current 30 and the second additional ripple current 32 flowing in the opposite polarity period p ₂ to the primary add capacitor C _C is shown. The first additional ripple current 30, the first switching element _{S 1} from the first winding _{L 1,} the second capacitor _{C 2,} back to the first winding _{L 1} flows through the primary additional capacitor _{C C.} The second additional ripple current 32 flows from the second winding L ₂ through the primary capacitor CA _A , the first switching element S ₁ , the first capacitor C ₁ , and the primary additional capacitor _CC, and flows through the second winding L ₂ Return to. Further, in FIG. 11 (a), the third additional ripple current 34 and the fourth additional ripple current 36 flowing in the opposite polarity period p ₂ to the secondary additional capacitor C _D is shown. The path through which the third additional ripple current 34 and the fourth additional ripple current 36 flow is the same as the same polarity period q ₁ .

FIG. 11 (b) first adding the ripple current 30 and the second additional ripple current 32 flowing through the same polarity period q ₂ to the primary add capacitor C _C is shown. The path through which the first additional ripple current 30 and the second additional ripple current 32 flow is the same as the reverse polarity period q ₂ .

Further, in FIG. 11 (b) third additional ripple current 34 and the fourth additional ripple current 36 flowing through the same polarity period q ₂ to the secondary additional capacitor C _D is shown. The path through which the third additional ripple current 34 and the fourth additional ripple current 36 flow is the same as the reverse polarity period q ₁ .

As shown in FIGS. 10 and 11, the first additional ripple current 30 and the second additional ripple current 32 flowing through the primary additional capacitor C _C in any of the periods is the opposite direction at the same value. Therefore, the ripple current flowing through the primary add capacitor C _C is suppressed. Similarly, the third additional ripple current 34 and the fourth additional ripple current 36 flowing through the secondary additional capacitor C _D in any of the periods is the opposite direction at the same value. Therefore, the ripple current flowing through the secondary additional capacitor C _D is suppressed.

As described above, the ripple suppression / power conversion device according to the present embodiment has the ripple suppression / primary circuit 26 (first switching circuit) and ripple suppression that are magnetically coupled by the core Fp as a magnetic path formed of a magnetic material. A secondary circuit 28 (second switching circuit) is provided, and power is transmitted between the ripple suppression / primary circuit 26 and the ripple suppression / secondary circuit 28.

The ripple suppression / primary circuit 26 includes a first loop including a first winding L ₁ provided on the core Fp, a first capacitor C ₁ , and a first switching element S ₁ , and a second volume provided on the core Fp. A path connecting the second loop including the wire L ₂ , the second capacitor C ₂ , and the second switching element S ₂ , the first switching element S ₁ and the first winding L ₁ , the second switching element S ₂ and and a, a primary capacitor C _{a (third} capacitor) provided between the path connecting the second winding L _2. The path connecting the first switching element S ₁ and the first capacitor C ₁ and the path connecting the second switching element S ₂ and the second capacitor C ₂ are commonly connected, and the first switching element S ₁ and the path connecting the second capacitor C ₂ are connected in common. The second switching element S ₂ turns on and off alternately.

The ripple suppression / secondary circuit 28 includes a third loop including a third winding L ₃ provided on the core Fp, a third capacitor C ₃ , and a third switching element S ₃ , and a fourth volume provided on the core Fp. A path connecting a fourth loop including a wire L ₄ , a fourth capacitor C ₄ , and a fourth switching element S ₄ , a third switching element S ₃ and a third winding L ₃ , a fourth switching element S ₄ and It is provided with a secondary capacitor C _B provided between the path connecting the fourth winding L ₄ and the path. The path connecting the third switching element S ₃ and the third capacitor C ₃ and the path connecting the fourth switching element S ₄ and the fourth capacitor C ₄ are commonly connected, and the third switching element S ₃ and the path connecting the fourth capacitor C ₄ are connected in common. The fourth switching element S ₄ turns on and off alternately.

The power corresponding to the phase difference (time difference) between the switching timing of the first switching element S ₁ and the second switching element S _{2 and} the switching timing of the third switching element S ₃ and the fourth switching element S ₄ suppresses ripple. It is transmitted between the primary circuit 26 and the ripple suppression / secondary circuit 28.

The ripple suppression / primary circuit 26 is a primary provided between a path connecting the first winding L ₁ and the first capacitor C ₁ and a path connecting the second winding L ₂ and the second capacitor C _2. - comprises an additional capacitor C _C, power from both ends of the primary additional capacitor C _C is input and output.

The ripple suppression / secondary circuit 28 is a secondary circuit provided between a path connecting the third winding L ₃ and the third capacitor C ₃ and a path connecting the fourth winding L ₄ and the fourth capacitor C _4. - comprises an additional capacitor C _D, the power from both ends of the secondary additional capacitor C _D is input.

According to the ripple suppression / power conversion device, the ripple current flowing in the circuit connected to the 5th terminal 5 and the 6th terminal 6 and the ripple current flowing in the circuit connected to the 7th terminal 7 and the 8th terminal 8 are suppressed. Will be done. This ripple suppressing effect is due to the fact that the ripple currents flowing in the opposite directions suppress each other. Therefore, the capacity of the primary additional capacitors C _C and secondary additional capacitor C _D may be smaller than the capacitance of the primary capacitors C _A and secondary capacitor C _B in the power conversion apparatus shown in Figure 1.

Further, similarly to the power converting apparatus according to the first embodiment, in the ripple suppressing power conversion device according to this embodiment, first winding L ₁ and the second winding L ₂ is provided on the primary side, the secondary side third winding L ₃ and the fourth winding L ₄ the power transmission is performed by winding two pairs is provided. In this case, it is expected that the transmission power will increase as compared with the case where the power is transmitted by a pair of windings as described above. Therefore, even if the trapezoidal current flowing through each winding is reduced during the same polarity period, sufficient power is transmitted and the loss based on the current flowing through each winding is reduced.

The secondary circuit 16 in the first embodiment may be replaced with the ripple suppression / secondary circuit 28 in the second embodiment. Similarly, the ripple suppression / secondary circuit 28 in the second embodiment may be replaced with the secondary circuit 16 in the first embodiment.

Further, the switching circuit on the primary side or the secondary side of the power conversion device according to the first embodiment may be replaced with a half-bridge switching circuit or a full-bridge switching circuit. Similarly, the switching circuit on the primary side or the secondary side of the ripple suppression / power conversion device according to the second embodiment may also be replaced with a half-bridge switching circuit or a full-bridge switching circuit.

FIG. 12A shows a half-bridge switching circuit. The half-bridge switching circuit includes an upper switching element S ₅ , a lower switching element S ₆ , an upper capacitor C ₅ , a lower capacitor C ₆ , an inter-terminal capacitor _CE , and a winding L. One end of the upper switching element S ₅ is connected to the terminal A, and one end of the lower switching element S ₆ is connected to the terminal B. The other end of the upper switching element S _{5 and} the other end of the lower switching element S ₆ are commonly connected. One end of the upper capacitor C ₅ is connected to the terminal A, and one end of the lower capacitor C ₆ is connected to the terminal B. The other end of the upper capacitor C _{5 and} the other end of the lower capacitor C ₆ are commonly connected. A winding L is connected between the connection points of the upper switching element S ₅ and the lower switching element S _{6 and} the connection points of the upper capacitor C ₅ and the lower capacitor C ₆ . An inter-terminal capacitor _CE is connected between the terminal A and the terminal B.

By upper switching element S ₅ and the lower switching element S ₆ is alternately turned on and off, the induced electromotive force generated in the coil L is applied to the upper capacitor C ₅ and the lower capacitor C _6, the upper capacitor C ₅ and the lower capacitor C ₆ is charged. Further, the inter-terminal capacitor _CE is charged by the combined voltage of the inter-terminal voltage of the upper capacitor C _{5 and} the inter-terminal voltage of the lower capacitor C ₆ . Further, when the upper switching element S ₅ and the lower switching element S ₆ are alternately turned on and off, the charging voltage of the upper capacitor C _{5 and} the charging voltage of the lower capacitor C ₆ are alternately applied to the winding L.

By making the phase of the switching timing on the primary side different from the phase of the switching timing on the secondary side, power is transmitted from the winding L to the terminals A and B, or power is transmitted from the terminals A and B to the winding L. Be transmitted.

FIG. 12B shows a full bridge switching circuit. In this circuit, the upper capacitor C ₅ and the lower capacitor C ₆ in FIG. 12A are replaced with the second upper switching element S ₇ and the second lower switching element S ₈ , respectively. The upper switching element S ₅ and the lower switching element S ₆ are alternately turned on and off, and the second upper switching element S ₇ and the second lower switching element S ₈ are also alternately turned on and off. The phases of the switching timings of the upper switching element S ₅ and the lower switching element S _{6 and} the switching timing phases of the second upper switching element S ₇ and the second lower switching element S ₈ are different by 180 °. By making the phase of the switching timing on the primary side different from the phase of the switching timing on the secondary side, power is transmitted from the winding L to the terminals A and B, or power is transmitted from the terminals A and B to the winding L. Be transmitted.

As another embodiment, the switching circuit on the primary side or the secondary side of the power conversion device according to the first embodiment may be replaced with a general power conversion circuit such as a step-up circuit or a step-down circuit. Similarly, the switching circuit on the primary side or the secondary side of the ripple suppression / power conversion device according to the second embodiment may also be replaced with a general power conversion circuit such as a step-up circuit or a step-down circuit.

1-8 1st to 8th terminals, 10 1st loop, 12 2nd loop, 14 primary circuit, 16 secondary circuit, 26 ripple suppression / primary circuit, 28 ripple suppression / secondary circuit, 30 1st additional ripple current, 32 the second additional ripple current, 34 third additional ripple current, 36 fourth additional ripple current, _{E A} DC power supply, _{C V} power source side capacitor, _{C t} intermediate capacitor, _{C L} load capacitor, _{R L} load, Fp core, L _{1 to} L ₄ 1st to 4th windings, C _{1 to} C ₄ 1st to 4th capacitors, C ₅ upper capacitor, C ₆ lower capacitor, _CE terminal capacitor, S _{1 to} S ₄ 1st to 4th switching element, _{S 5} on the switching element, _{S 6} lower switching element, _{S 7} second upper switching element, _{S 8} second lower switching element, _{C A} primary capacitor, _{C B} secondary capacitor, _{C C} primary additional capacitor, _CD secondary / additional capacitor, L winding.

Claims (6)

In a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material.
At least one of the first switching circuit and the second switching circuit
A first winding provided in the magnetic path, a first capacitor, and a first loop including a first switching element.
A second winding provided in the magnetic path, a second capacitor, and a second loop including a second switching element.
A path for connecting the first switching element and the first winding and a third capacitor provided between the path for connecting the second switching element and the second winding are provided.
The path connecting the first switching element and the first capacitor and the path connecting the second switching element and the second capacitor are commonly connected.
A power conversion device characterized in that power is input and output from both ends of the third capacitor. In a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material.
At least one of the first switching circuit and the second switching circuit
A first winding provided in the magnetic path, a first capacitor, and a first loop including a first switching element.
A second winding provided in the magnetic path, a second capacitor, and a second loop including a second switching element.
A third capacitor provided between the path connecting the first switching element and the first winding and the path connecting the second switching element and the second winding.
A fourth capacitor provided between a path connecting the first winding and the first capacitor and a path connecting the second winding and the second capacitor,
With
The path connecting the first switching element and the first capacitor and the path connecting the second switching element and the second capacitor are commonly connected.
A power conversion device characterized in that power is input / output from both ends of the fourth capacitor. In a power conversion device including a first switching circuit and a second switching circuit coupled by a magnetic path formed of a magnetic material.
Each of the first switching circuit and the second switching circuit
A first winding provided in the magnetic path, a first capacitor, and a first loop including a first switching element.
A second winding provided in the magnetic path, a second capacitor, and a second loop including a second switching element.
A path for connecting the first switching element and the first winding and a third capacitor provided between the path for connecting the second switching element and the second winding are provided.
The path connecting the first switching element and the first capacitor and the path connecting the second switching element and the second capacitor are commonly connected.
The first switching element and the second switching element are alternately turned on and off,
The electric power according to the time difference between the switching timing in the first switching circuit and the switching timing in the second switching circuit is transmitted between the first switching circuit and the second switching circuit. Conversion device. In the power conversion device according to claim 3,
A power conversion device, wherein in each of the first switching circuit and the second switching circuit, electric power is input / output from both ends of the third capacitor. In the power conversion device according to claim 3,
Each of the first switching circuit and the second switching circuit
A fourth capacitor provided between a path connecting the first winding and the first capacitor and a path connecting the second winding and the second capacitor is provided.
A power conversion device characterized in that power is input / output from both ends of the fourth capacitor. In the power conversion device according to claim 3,
In one of the first switching circuit and the second switching circuit, power is input / output from both ends of the third capacitor.
The other of the first switching circuit and the second switching circuit
A fourth capacitor provided between a path connecting the first winding and the first capacitor and a path connecting the second winding and the second capacitor is provided.
A power conversion device characterized in that power is input / output from both ends of the fourth capacitor.