JP2020088945A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of suppressing a surge component superimposed on an output voltage. A power conversion device 100 includes an inverter circuit 105 including a switching element, a transformer 106 in which a primary side is connected to an output of the inverter circuit 105, and a rectifier in which an input is connected to a secondary side of the transformer 106. Smoothing the ripple contained in the output voltage of the circuit 107 and the rectifier circuit 107, and smoothing the ripple contained in the output voltage of the first reactor L1 connected in series with the output of the rectifier circuit 107 and the rectifier circuit 107. A first capacitor C1 connected in series to the output of the rectifier circuit 107, and a second capacitor connected in parallel to the output of the rectifier circuit 107 with the first capacitor C1 and having a smaller capacitance than the first capacitor C1. It is equipped with C2. [Selection diagram] Fig. 1

Description

The present invention relates to a power converter, and more particularly to a power converter including an inverter circuit including a switching element.

A power converter represented by a DC/DC converter or the like often includes an inverter circuit including a switching element. Such a power conversion device includes a capacitor for smoothing ripples generated due to the switching operation of the inverter circuit, that is, a smoothing capacitor. The capacity of the smoothing capacitor is determined based on the ripple frequency, the power input to the smoothing capacitor, and the like.

In addition, when the inverter circuit performs the switching operation, a high frequency surge voltage is generated in each part of the circuit due to the parasitic inductance and the parasitic capacitance of the circuit forming the power conversion device. The frequency of this surge voltage is much higher than the frequency of the ripple.

Due to its parasitic inductance component, the smoothing capacitor has a high impedance at surge voltage frequencies much higher than the ripple frequency. Therefore, the smoothing capacitor cannot sufficiently absorb the surge voltage.

As a conventional technique, an invention has been proposed in which the structure of a bus bar of a circuit included in a power conversion device is devised to adjust the inductance component of the circuit to suppress a surge component superimposed on an output voltage (for example, a patent Reference 1).

JP, 2008-61282, A

However, as described in Patent Document 1, there is a limit in adjusting the inductance component of the circuit by devising the structure of the bus bar. Therefore, the method described in Patent Document 1 has a problem that the surge component superimposed on the output voltage of the power conversion device cannot be sufficiently suppressed.

The present invention is for solving such a problem, and an object thereof is to provide a power conversion device capable of suppressing a surge component superimposed on an output voltage.

In order to solve the above problems, a power converter according to the present invention has an inverter circuit including a switching element, a transformer whose primary side is connected to the output of the inverter circuit, and an input on the secondary side of the transformer. A rectifier circuit connected to the rectifier circuit, smoothing ripples contained in the output voltage of the rectifier circuit, and a first reactor serially connected to the output of the rectifier circuit, and ripples contained in the output voltage of the rectifier circuit, and A first capacitor that is connected in series to the output of the rectifier circuit and a second capacitor that is connected to the output of the rectifier circuit in parallel with the first capacitor and has a smaller capacity than the first capacitor are provided.

According to the power converter of the present invention, it is possible to suppress the surge component that is superimposed on the output voltage.

It is a circuit diagram of the power converter device which concerns on Embodiment 1 of this invention. FIG. 2 is a schematic diagram of a switching operation of the power conversion device of FIG. 1 and voltage values and current values of respective parts. It is a figure which shows a part of electric power converter device which concerns on Embodiment 2 of this invention. It is a figure which shows a part of electric power converter device which concerns on Embodiment 3 of this invention. It is a part which shows a part of electric power converter device which concerns on Embodiment 4 of this invention. It is a part which shows a part of electric power converter device which concerns on Embodiment 5 of this invention. It is a figure which shows a part of electric power converter device which concerns on Embodiment 6 of this invention. It is a circuit diagram of the power converter device which concerns on Embodiment 7 of this invention. It is a circuit diagram of the power converter device which concerns on Embodiment 8 of this invention. It is a circuit diagram of the power converter device which concerns on Embodiment 9 of this invention.

Hereinafter, embodiments of a power conversion device disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the embodiments shown below are examples, and the present invention is not limited by these embodiments.

Embodiment 1.
1 is a circuit diagram of a power conversion device 100 according to Embodiment 1 of the present invention.
The DC power supply 1 is connected to the input terminals P100 and N100 of the power converter 100. The load 2 is connected to the output terminals P103 and N103 of the power converter 100.

The power conversion device 100 includes a capacitor C0, an inverter circuit 105, a transformer 106, a rectifier circuit 107, a first reactor L1 and a first capacitor C1.

The capacitor C0 is connected in parallel to the input terminals P100 and N100 of the power converter 100. The capacitor C0 smoothes the input voltage V1 of the power converter 100.

The inverter circuit 105 includes first to fourth switching elements 101 to 104. By the switching operations of the first to fourth switching elements 101 to 104, the DC power input to the power conversion device 100 is converted into AC power.

The output of the inverter circuit 105 is connected to the primary side of the transformer 106. The input of the rectifier circuit 107 is connected to the secondary side of the transformer 106. In FIG. 1, V3 is a voltage on the primary side of the transformer 106, and I1 is a current on the primary side of the transformer 106.

The rectifier circuit 107 includes a first diode D1 and a second diode D2. The rectifier circuit 107 rectifies the alternating current output from the secondary side of the transformer 106.

To the output of the rectifier circuit 107, the first reactor L1 is connected in series and the first capacitor C1 is connected in parallel. The first reactor L1 and the first capacitor C1 smooth the output voltage of the rectifier circuit 107.

A second capacitor C2 having a smaller capacity than the first capacitor C1 is connected to the output of the rectifier circuit 107 in parallel with the first capacitor C1. The function of the second capacitor C2 will be described later.

Furthermore, the power conversion device 100 includes a voltage measurement circuit 108 that measures the output voltage V2 of the power conversion device 100 and a control circuit 109 that controls the switching operation of the first to fourth switching elements 101 to 104. ..

In FIG. 1, I2 is a current flowing through the first reactor L1, I3 is an output current of the power conversion device 100, and I4 is a current flowing through the negative electrode side of the power conversion device 100.

Next, the operation of the power converter 100 of FIG. 1 will be described with reference to FIG.
In FIG. 2, SW14 is an ON-OFF waveform of the first switching element 101 and the fourth switching element 104. SW23 is an OF-OFF waveform of the second switching element 102 and the third switching element 103.

Further, as described above, V3 is the voltage on the primary side of the transformer 106, and I2 is the current flowing through the first reactor L1.

First, when the first switching element 101 and the fourth switching element 104 are turned on, the voltage V3 is applied to the primary side of the transformer 106, and the voltage V3 of the primary side is applied to the secondary side of the transformer 106. Is divided by the turns ratio γ of the transformer 106 to generate a voltage.

At this time, a voltage equal to the difference between the voltage on the secondary side of the transformer 106 and the output voltage V2 of the power converter 100 is applied to both ends of the first reactor L1, and the current I2 increases. Further, a current I1 having a value obtained by dividing the current I2 flowing through the first reactor L1 by the winding ratio γ flows through the primary side of the transformer 106.

Next, when the first switching element 101 and the fourth switching element 104 are turned off, the voltage V3 on the primary side of the transformer 106 becomes 0 and the current I1 on the primary side of the transformer 106 also becomes 0. .. Also, the voltage on the secondary side of the transformer 106 becomes zero.

At this time, the output voltage V2 of the power converter 100 is applied to the first reactor L1, and the current I2 decreases. In addition, a current having the same value as the current I2 flowing through the first reactor L1 flows into the secondary side of the transformer 106 by the center tap.

Next, when the second switching element 102 and the third switching element 103 are turned ON, the voltage V3 is applied to the primary side of the transformer 106, and the voltage of the primary side is applied to the secondary side of the transformer 106. A voltage having a value obtained by dividing V3 by the turns ratio γ is generated.

At this time, a voltage equal to the difference between the voltage on the secondary side of the transformer 106 and the output voltage V2 of the power converter 100 is applied to both ends of the first reactor L1, and the current I2 increases. Further, a current I1 having a value obtained by dividing the current I2 flowing through the first reactor L1 by the winding ratio γ flows through the primary side of the transformer 106.

Next, when the second switching element 102 and the third switching element 103 are turned off, the voltage V3 on the primary side of the transformer 106 becomes 0, and the current I1 on the primary side of the transformer 106 also becomes 0. .. Also, the voltage on the secondary side of the transformer 106 becomes zero.

At this time, the output voltage V2 of the power converter 100 is applied to the first reactor L1, and the current I2 decreases. In addition, a current having the same value as the current I2 flowing through the first reactor L1 flows into the secondary side of the transformer 106 by the center tap.

To summarize the above operation, when the first and fourth switching elements 101 and 104 are ON and the second and third switching elements 102 and 103 are OFF, or the first and fourth switching elements 101 and 104 are When 104 is OFF and the second and third switching elements 102 and 103 are ON, a current having a value obtained by dividing the current I2 flowing through the first reactor L1 by the winding ratio γ is provided on the primary side of the transformer 106. Flows.

Further, when the first and fourth switching elements 101 and 104 are ON and the second and third switching elements 102 and 103 are OFF, or the first and fourth switching elements 101 and 104 are OFF, and When the second and third switching elements 102 and 103 are ON, the current I2 flowing through the first reactor L1 increases.

When all the first to fourth switching elements 101 to 104 are off, the current I2 flowing through the first reactor L1 decreases.

Here, as described above, in the output of the rectifier circuit 107, the ripples caused by the switching operations of the first to fourth switching elements 101 to 104 are smoothed mainly by the first capacitor C1. .. The capacitance of the first capacitor C1 is determined based on the ripple frequency, the output power from the rectifier circuit 107, and the like.

In addition, when the first to fourth switching elements 101 to 104 perform a switching operation, a high frequency surge voltage is generated in each part of the circuit due to the parasitic inductance and the parasitic capacitance of the circuit configuring the power conversion device 100. To do. The frequency of this surge voltage is much higher than the frequency of the ripple. When this surge voltage is superimposed on the output voltage V2 of the power converter 100, it adversely affects the load 2.

If there is no parasitic inductance component in the first capacitor C1, the first capacitor C1 has a sufficiently low impedance even at a surge voltage frequency much higher than the ripple frequency. In that case, the surge voltage is absorbed by the first capacitor C1, and the output voltage V2 of the power conversion device 100 has a waveform as shown by V201 in FIG.

However, in reality, since the first capacitor C1 has a parasitic inductance component, the first capacitor C1 has a high impedance at the frequency of the surge voltage. Therefore, the surge voltage cannot be sufficiently absorbed by the first capacitor C1. In that case, the output voltage V2 of the power conversion device 100 has a waveform in which the surge component is superimposed, as indicated by V202 in FIG.

In order to deal with such a problem, in the first embodiment of the present invention, the output of the rectifier circuit 107 is provided in parallel with the first capacitor C1 and the second capacitor C2 having a smaller capacitance than the first capacitor C1. Are connected. The capacitance of the second capacitor C2 is determined based on the frequency of the surge voltage so that the surge voltage can be absorbed. In other words, the capacitance of the second capacitor C2 is determined to have a sufficiently low impedance at the frequency of the surge voltage.

As described above, in the power conversion device 100 according to Embodiment 1 of the present invention, the output of the rectifier circuit is connected in parallel with the first capacitor, and the second capacitor having a smaller capacity than the first capacitor is connected. It has a capacitor. This makes it possible to suppress the surge component superimposed on the output voltage.

Since the capacitance of the second capacitor C2 is smaller than that of the first capacitor C1, the second capacitor C2 can be made smaller than the first capacitor C1. As a result, the second capacitor C2 can be mounted by wiring having a lower impedance than that of the first capacitor C1.

Embodiment 2.
The configuration of power conversion device 200 according to Embodiment 2 of the present invention will be described with reference to FIG. Note that the second to sixth embodiments described below are variations of the mounting form having the first embodiment as a basic structure. Therefore, detailed description of the same or similar configuration as that of the first embodiment is omitted.

The mounting form shown in FIG. 3 is obtained by extracting points P101 to P102 and points N101 to N102 in the circuit diagram of FIG.

The power conversion device 200 includes a first bus bar 210 and a second bus bar 211 that form an output line.

The positive electrode of the first capacitor C201 is electrically connected to the first bus bar 210 via the first terminal 212. The negative electrode of the first capacitor C201 is electrically connected to the second bus bar 211 via the second terminal 213.

The positive electrode of the second capacitor C202 is electrically connected to the first bus bar 210 via the third terminal 214. The negative electrode of the second capacitor C202 is electrically connected to the second bus bar 210 via the fourth terminal 215.

The first capacitor C201 and the second capacitor C202 are each enclosed in a dedicated case.

As described in the first embodiment, the capacitance of the second capacitor C202 is smaller than the capacitance of the first capacitor C201. Therefore, the case of the second capacitor C202 is smaller than the case of the first capacitor C201.

In addition, the first capacitor C201 branches the first terminal 212 and the second terminal 213 from the first bus bar 210 and the second bus bar 211 of the main circuit due to restrictions such as size, arrangement of parts, and weight. The first bus bar 210 and the second bus bar 211 are arranged apart from each other.

On the other hand, the second capacitor C202 is arranged between the first bus bar 210 and the second bus bar 211 because the restrictions on the size, component arrangement, weight, etc. are smaller than those of the first capacitor C101. There is. Since the second capacitor C202 is arranged near the first bus bar 210 and the second bus bar 211, the parasitic inductance can be suppressed lower than that of the first capacitor C101.

Embodiment 3.
The configuration of power conversion device 300 according to Embodiment 3 of the present invention will be described with reference to FIG.

The mounting form shown in FIG. 4 is obtained by extracting points P101 to P102 and points N101 to N102 in the circuit diagram of FIG.

The power conversion device 300 includes a first bus bar 210 and a second bus bar 211 that form an output line.

The positive electrode of the first capacitor C301 is electrically connected to the first bus bar 210 via the first terminal 312. The negative electrode of the first capacitor C301 is electrically connected to the second bus bar 211 via the second terminal 313.

Further, the second capacitor C302 composed of a plurality of capacitors is mounted on the dedicated substrate 316.

The positive electrode of the second capacitor C302 is electrically connected to the fifth terminal 317 of the dedicated substrate 316. The negative electrode of the second capacitor C302 is electrically connected to the sixth terminal 318 of the dedicated substrate 316.

The fifth terminal 317 of the dedicated substrate 316 is electrically connected to the first bus bar 210. The sixth terminal 318 of the dedicated board 316 is electrically connected to the second bus bar 211.

In the third embodiment, the second capacitor C302 is configured by a plurality of capacitors, and the capacitance, the number of series, the number of parallels, and the like of each capacitor are finely set, so that the capacitance, withstand voltage, and the like of the second capacitor C302 can be freely set. Can be adjusted to.

Fourth Embodiment
The configuration of power conversion device 400 according to Embodiment 4 of the present invention will be described with reference to FIG.

The mounting form shown in FIG. 5 is obtained by extracting points P101 to P102 and points N101 to N102 in the circuit diagram of FIG.

The power conversion device 400 includes a first bus bar 210 and a second bus bar 211 that form an output line.

The positive electrode of the first capacitor C401 is electrically connected to the first bus bar 210 via the first terminal 412. The negative electrode of the first capacitor C401 is electrically connected to the second bus bar 211 via the second terminal 413.

Further, the second capacitor C402 composed of a plurality of capacitors is mounted on the dedicated substrate 416.

The positive electrode of the second capacitor C402 is electrically connected to the fifth terminal 417 of the dedicated substrate 416. The negative electrode of the second capacitor C402 is electrically connected to the sixth terminal 418 of the dedicated substrate 416.

The fifth terminal 417 of the dedicated substrate 416 is electrically connected to the first bus bar 210. The sixth terminal 418 of the dedicated board 416 is electrically connected to the second bus bar 211.

The voltage across the second capacitor C402 is equal to the output voltage V2 of the power converter 400. Therefore, the voltage measuring circuit 108 is also mounted on the dedicated substrate 416.

One measurement terminal of the voltage measurement circuit 108 is electrically connected to the positive electrode of the second capacitor C402 by pattern wiring on the dedicated substrate 416. The other measurement terminal of the voltage measurement circuit 108 is electrically connected to the negative electrode of the second capacitor C402 by pattern wiring on the dedicated substrate 416.

As a result, the second capacitor C402 and the voltage measurement circuit 108 share the fifth terminal 417 which is responsible for connection to the first bus bar 210 and the sixth terminal 418 which is responsible for connection to the second bus bar 211. Therefore, the number of parts can be reduced.

Embodiment 5.
The configuration of power conversion device 500 according to Embodiment 5 of the present invention will be described with reference to FIG.

The mounting form shown in FIG. 6 is obtained by extracting points P101 to P102 and points N101 to N102 in the circuit diagram of FIG.

The power conversion device 500 includes a first bus bar 210 and a second bus bar 211 that form an output line.

The positive electrode of the first capacitor C501 is electrically connected to the first bus bar 210 via the first terminal 512. The negative electrode of the first capacitor C501 is electrically connected to the second bus bar 211 via the second terminal 513.

Further, the second capacitor C502 composed of a plurality of capacitors is mounted on the dedicated substrate 516.

The positive electrode of the second capacitor C502 is electrically connected to the fifth terminal 517 of the dedicated substrate 516. The negative electrode of the second capacitor C502 is electrically connected to the sixth terminal 518 of the special substrate 516.

The fifth terminal 517 of the dedicated substrate 516 is electrically connected to the first bus bar 210. The sixth terminal 518 of the dedicated substrate 516 is electrically connected to the second bus bar 211.

Further, the voltage across the second capacitor C502 is equal to the output voltage V2 of the power conversion device 500. Therefore, the voltage measuring circuit 108 is also mounted on the dedicated substrate 516.

Further, the control circuit 109 controls the switching operation of the first to fourth switching elements 101 to 104 using the measurement value of the voltage measurement circuit 108. Therefore, the control circuit 109 is also mounted on the dedicated substrate 516, and the voltage measurement circuit 108 and the control circuit 109 are electrically connected by the pattern wiring on the dedicated substrate 516.

As a result, the board on which the control circuit 109 is mounted can be integrated with the dedicated board 516, so that the number of parts can be reduced.

Sixth embodiment.
The configuration of power conversion device 600 according to Embodiment 6 of the present invention will be described with reference to FIG. 7.

The mounting form shown in FIG. 7 is obtained by extracting points P101 to P102 and points N101 to N102 in the circuit diagram of FIG.

The power conversion device 600 is provided on the first bus bar 210 and the second bus bar 211 that form the output line.

The positive electrode of the first capacitor C601 is electrically connected to the first bus bar 210 via the first terminal 612. The negative electrode of the first capacitor C601 is electrically connected to the second bus bar 211 via the second terminal 613.

Further, the second capacitor C602 including a plurality of capacitors is mounted on the dedicated substrate 616.

The positive electrode of the second capacitor C602 is electrically connected to the fifth terminal 617 of the dedicated substrate 616. The negative electrode of the second capacitor C602 is electrically connected to the sixth terminal 618 of the dedicated substrate 616.

The fifth terminal 617 of the dedicated substrate 616 is electrically connected to the first terminal 612 of the first capacitor C601. The sixth terminal 618 of the dedicated substrate 616 is electrically connected to the second terminal 613 of the first capacitor C601.

In the sixth embodiment, it is not necessary to directly connect the fifth terminal 617 of the special board 616 to the first bus bar 210, and it is necessary to directly connect the sixth terminal 618 of the special board 616 to the second bus bar 211. Nor.

Therefore, in the sixth embodiment, compared with the fifth terminal 317 and the sixth terminal 318 of the dedicated substrate 316 according to the third embodiment shown in FIG. 4, the fifth terminal 617 and the sixth terminal 617 of the dedicated substrate 616 are compared. It is not necessary to form the tip of the terminal 618 of the large. As a result, the components and the mounting space can be downsized.

Embodiment 7.
The configuration of power conversion device 700 according to Embodiment 7 of the present invention will be described with reference to the circuit diagram of FIG.

In power conversion device 700, second reactor L702 is connected in series at the subsequent stage of first capacitor C1 and second capacitor C2. The value of the second reactor L702 is determined to have an impedance higher than that of the second capacitor C2 at the frequency of the surge voltage.

The presence of the second reactor L702 increases the impedance of the subsequent stage of the first capacitor C1 and the second capacitor C2. Therefore, in the seventh embodiment, even a slight surge current that has flowed out to the output terminals P103, N103 side without flowing into the second capacitor C2 in the previous embodiments is transferred to the second capacitor C2. It will begin to flow. As a result, a larger amount of surge component is absorbed by the second capacitor C2, so that the surge component superimposed on the output voltage V2 can be further suppressed.

Eighth embodiment.
The configuration of power conversion device 800 according to Embodiment 8 of the present invention will be described with reference to the circuit diagram of FIG.

In the power conversion device 800, points N101 to N102 on the negative side of the output line are configured by a housing 819 that houses the power conversion device 800. The center tap of the transformer 106 is electrically connected to the housing 819 at a point N101.

In this case, due to the inductance component of the casing 819, the impedance between the output terminal N103 and the first capacitor C1 becomes high impedance, and the surge voltage rises.

To deal with this, in the eighth embodiment, the negative electrode side of the second capacitor C2 is connected to the transformer 106 side rather than the point N101 at which the center tap of the transformer 106 is connected to the housing 819. Has been done.

With such a connection, even when the points N101 to N102 are formed by the housing 819, the surge component superimposed on the output voltage V2 can be suppressed.

Ninth Embodiment
The configuration of power conversion device 900 according to Embodiment 9 of the present invention will be described with reference to the circuit diagram of FIG. 10.

In the power conversion device 900, the points N101 to N102 on the negative side of the output line are configured by a housing 919 that houses the power conversion device 900. The center tap of the transformer 106 is connected to one end of the first reactor L1.

The anode of the first diode D901 is electrically connected to the housing 919, and the cathode of D901 of the first diode is connected to the secondary side positive electrode of the transformer 106. The anode of the second diode D902 is electrically connected to the housing 919, and the cathode of the second diode D902 is connected to the negative electrode on the secondary side of the transformer 106.

Also in this case, due to the inductance component of the housing 919, the impedance between the output terminal N103 and the first capacitor C1 becomes high impedance, and the surge voltage rises.

To deal with this, in the ninth embodiment, the negative electrode side of the second capacitor C2 is closer to the negative electrode side than the point N101 at which the anode of the second diode D902 forming the rectifying circuit 907 is connected to the housing 919. It is connected to the second diode D902 side.

By connecting in this way, even when the points N101 to N102 are formed by the housing 919, the surge component superimposed on the output voltage V2 can be suppressed.

100, 200, 300, 400, 500, 600, 700, 800, 900 Power conversion device, 101 1st switching element, 102 2nd switching element, 103 3rd switching element, 104 4th switching element, 105 Inverter circuit, 106 transformer, 107,907 rectifier circuit, 108 voltage measuring circuit, 109 control circuit, 210 first bus bar, 211 second bus bar, 212, 312, 412, 512, 612 first terminal, 213. 313, 413, 513, 613 2nd terminal, 214 3rd terminal, 215 4th terminal, 316, 416, 516, 616 Dedicated substrate, 317, 417, 517, 617 5th terminal, 318, 418, 518,618 sixth terminal, 819,919 housing, C1, C201, C301, C401, C501, C601 first capacitor, C2, C202, C302, C402, C502, C602 second capacitor, D1, D901 1 diode, D2, D902 2nd diode, L1 1st reactor, L702 2nd reactor.

In order to solve the above problems, a power converter according to the present invention has an inverter circuit including a switching element, a transformer whose primary side is connected to the output of the inverter circuit, and an input on the secondary side of the transformer. A rectifier circuit connected to the rectifier circuit, smoothing ripples contained in the output voltage of the rectifier circuit, and a first reactor serially connected to the output of the rectifier circuit, and ripples contained in the output voltage of the rectifier circuit, and A first capacitor connected in parallel to the output of the rectifier circuit; and a second capacitor connected to the output of the rectifier circuit in parallel with the first capacitor and having a smaller capacitance than the first capacitor , The capacity of the capacitor is determined so as to absorb the surge voltage based on the frequency of the surge voltage generated in the power conversion device, and a part of the negative side of the output line of the power conversion device is connected to the power conversion device. The center tap of the transformer is electrically connected to the housing, and the negative electrode of the second capacitor is more than the point where the center tap of the transformer is electrically connected to the housing. Connected to the transformer side.
Another power converter according to the present invention is an inverter circuit including a switching element, a transformer whose primary side is connected to the output of the inverter circuit, and a rectifier circuit whose input is connected to the secondary side of the transformer. And a ripple contained in the output voltage of the rectifier circuit, smoothing the ripple contained in the first reactor connected in series with the output of the rectifier circuit and the output voltage of the rectifier circuit, and A first capacitor connected in parallel and a second capacitor connected in parallel to the first capacitor at the output of the rectifier circuit and having a smaller capacitance than the first capacitor are provided, and the capacitance of the second capacitor is , It is determined to absorb the surge voltage based on the frequency of the surge voltage generated in the power conversion device, and a part of the negative side of the output line of the power conversion device depends on the housing that houses the power conversion device. The rectifier circuit is configured such that the anode is electrically connected to the casing and the first diode whose anode is electrically connected to the casing and whose cathode is connected to the positive electrode on the secondary side of the transformer. And a second diode whose cathode is connected to the negative electrode on the secondary side of the transformer, wherein the negative electrode of the second capacitor is more than the point where the anode of the second diode is electrically connected to the housing. It is connected to the side of the second diode.
Another power converter according to the present invention is an inverter circuit including a switching element, a transformer whose primary side is connected to the output of the inverter circuit, and a rectifier circuit whose input is connected to the secondary side of the transformer. And a ripple contained in the output voltage of the rectifier circuit, smoothing the ripple contained in the first reactor connected in series with the output of the rectifier circuit and the output voltage of the rectifier circuit, and A first capacitor connected in parallel and a second capacitor connected in parallel to the first capacitor at the output of the rectifier circuit and having a smaller capacitance than the first capacitor are provided, and the capacitance of the second capacitor is Further comprising a second reactor that is determined based on the frequency of the surge voltage generated in the power conversion device so as to absorb the surge voltage, and that is connected in series to the subsequent stage of the first capacitor and the second capacitor, The value of the second reactor is determined to have a higher impedance than the second capacitor at the frequency of the surge voltage.

Claims (12)

An inverter circuit including a switching element,
A transformer whose primary side is connected to the output of the inverter circuit;
A rectifier circuit whose input is connected to the secondary side of the transformer,
A first reactor that smoothes ripples contained in the output voltage of the rectifier circuit and that is connected in series to the output of the rectifier circuit;
A first capacitor that smoothes ripples contained in the output voltage of the rectifier circuit and that is connected in series to the output of the rectifier circuit;
A power conversion device comprising: a second capacitor connected to the output of the rectifier circuit in parallel with the first capacitor and having a smaller capacity than the first capacitor. The power conversion device according to claim 1, wherein the capacitance of the second capacitor is determined so as to absorb the surge voltage based on the frequency of the surge voltage generated in the power conversion device. A part of the output line of the power conversion device includes a first bus bar and a second bus bar,
The positive electrode of the first capacitor is electrically connected to the first bus bar via a first terminal,
The power converter according to claim 2, wherein the negative electrode of the first capacitor is electrically connected to the second bus bar via a second terminal. The positive electrode of the second capacitor is electrically connected to the first bus bar via a third terminal,
The power converter according to claim 3, wherein the negative electrode of the second capacitor is electrically connected to the second bus bar via a fourth terminal. The second capacitor is composed of a plurality of capacitors,
Further comprising a dedicated substrate on which the second capacitor is mounted,
The positive electrode of the second capacitor is electrically connected to the fifth terminal of the dedicated substrate,
The power converter according to claim 3, wherein the negative electrode of the second capacitor is electrically connected to the sixth terminal of the dedicated substrate. Further comprising a voltage measurement circuit for measuring the output voltage of the power converter,
The voltage measurement circuit is mounted on the dedicated board,
One measurement terminal of the voltage measurement circuit is electrically connected to the fifth terminal of the dedicated substrate,
The power conversion device according to claim 5, wherein the other measurement terminal of the voltage measurement circuit is electrically connected to the sixth terminal of the dedicated substrate. Further comprising a control circuit for controlling the switching operation of the inverter circuit,
The control circuit is mounted on the dedicated board,
The power converter according to claim 6, wherein the control circuit is electrically connected to the voltage measurement circuit. The fifth terminal of the dedicated substrate is electrically connected to the first bus bar,
The power conversion device according to claim 5, wherein the sixth terminal of the dedicated substrate is electrically connected to the second bus bar. The fifth terminal of the dedicated substrate is electrically connected to the first terminal,
The power conversion device according to claim 5, wherein the sixth terminal of the dedicated substrate is electrically connected to the second terminal. A part of the negative side of the output line of the power conversion device is configured by a housing that houses the power conversion device,
The center tap of the transformer is electrically connected to the housing,
The power conversion device according to claim 2, wherein the negative electrode of the second capacitor is connected to the transformer side with respect to a point where the center tap of the transformer is electrically connected to the housing. A part of the negative side of the output line of the power conversion device is configured by a housing that houses the power conversion device,
In the rectifier circuit, an anode is electrically connected to the casing, and a first diode whose cathode is connected to a secondary side positive electrode of the transformer and an anode is electrically connected to the casing. And a second diode whose cathode is connected to the negative electrode on the secondary side of the transformer,
The power conversion according to claim 2, wherein the negative electrode of the second capacitor is connected to the second diode side with respect to the point where the anode of the second diode is electrically connected to the housing. apparatus. Further comprising a second reactor connected in series to the latter stage of the first capacitor and the second capacitor,
The power conversion device according to claim 2, wherein the value of the second reactor is determined so as to have an impedance higher than that of the second capacitor at the frequency of the surge voltage.

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