Power conversion device and circuit constant determination method

Abstract

To provide a technique capable of suppressing radiation noise.SOLUTION: A power conversion device 1 includes: an inverter circuit 40 including a semiconductor switch SW; a DC line 30 including a positive line 30P and a negative line 30N and inputting DC to the invertor circuit 40; a pair of DC reactors 70P and 70N provided in the positive line 30P and the negative line 30N; an inter-line capacitor 80 provided so as to connect each end of an invertor circuit 40 side in each of the DC reactor 70P of the positive line 30P and the DC reactor 70N of the negative line 30N; and a ground capacitor 85 provided so as to connect between an end of the inverter circuit 40 side in the DC reactor 70N of the negative line 30N and a ground GND.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power conversion device and the like. [Background technology]

[0002] For example, a technique is known for suppressing electromagnetic noise caused by a switching circuit including a switching element as a noise source (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 079617 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, for example, a pair of DC reactors or common-mode choke coils for suppressing electromagnetic noise may be provided on the DC line on the input side of a switching circuit. In this case, high-frequency noise current may circulate between the DC line and ground via the pair of DC reactors or common-mode choke coils and parasitic capacitance between the switching circuit and ground. This may increase the radiated noise, for example, by causing part of the high-frequency noise current to leak to the outside as a common-mode current or by causing the DC line itself to become a radiation source.

[0005] In view of the above problems, an object of the present invention is to provide a technology capable of suppressing radiation noise. [Means for solving the problem]

[0006] In order to achieve the above object, in one embodiment of the present disclosure, a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a pair of DC reactors provided on the positive line and the negative line; a first capacitor provided to connect ends of the DC reactor on the positive line and the DC reactor on the negative line on the side of the switching circuit or between ends of the DC reactor on the opposite side to the switching circuit; a second capacitor provided to connect an end of the DC reactor on the positive line or the negative line on the side of the switching circuit or on the opposite side to the switching circuit and a conductive portion corresponding to a reference potential; A power converter is provided.

[0007] In another embodiment of the present disclosure, a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a common mode choke coil provided on the DC line; a third capacitor provided to connect ends of the positive line and the negative line of the common mode choke coil on the switching circuit side or between ends of the positive line and the negative line of the common mode choke coil on the opposite side to the switching circuit; a fourth capacitor provided to connect an end of the common mode choke coil on the switching circuit side or on the opposite side to the switching circuit of the positive line or negative line coil and a conductive part corresponding to a reference potential; A power converter is provided.

[0008] In still another embodiment of the present disclosure, a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a pair of DC reactors provided on the positive line and the negative line; a first capacitor provided to connect ends of the DC reactor on the positive line and the DC reactor on the negative line on the side of the switching circuit or between ends of the DC reactor on the opposite side to the switching circuit; a second capacitor provided to connect an end of the DC reactor on the positive line or the negative line on the side of the switching circuit or on the side opposite to the switching circuit and a conductive part corresponding to a reference potential, determining a capacitance of the second capacitor so that a resonance frequency of a path circulating between the DC line and the conductive part of the reference potential via a capacitance component between the switching circuit and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the positive line and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the negative line and the conductive part corresponding to the reference potential, and the second capacitor, is smaller than a predetermined value set to 1 MHz or more; A method for determining circuit constants is provided.

[0009] In still another embodiment of the present disclosure, a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a common mode choke coil provided on the DC line; a third capacitor provided to connect ends of the positive line and the negative line of the common mode choke coil on the switching circuit side or between ends of the positive line and the negative line of the common mode choke coil on the opposite side to the switching circuit; a fourth capacitor provided to connect an end of the positive line or negative line coil on the switching circuit side or on the opposite side to the switching circuit and a conductive part corresponding to a reference potential in the common mode choke coil, determining a capacitance of the fourth capacitor so that a resonance frequency of a path circulating between the DC line and the conductive part of the reference potential via a capacitance component between the switching circuit and the conductive part corresponding to the reference potential, a capacitance component between the positive line coil in the common mode choke coil and the conductive part corresponding to the reference potential, a capacitance component between the negative line coil in the common mode choke coil and the conductive part corresponding to the reference potential, and the fourth capacitor, is smaller than a predetermined value set to 1 MHz or more; A method for determining circuit constants is provided. [Effects of the Invention]

[0010] According to the above-described embodiment, radiation noise can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a configuration of a first example of a power conversion device. [Figure 2] FIG. 2 is a diagram showing a first example of an arrangement structure of line capacitors and ground capacitors. [Figure 3] FIG. 10 is a diagram showing a second example of the layout structure of the line capacitors and the ground capacitors. [Figure 4] FIG. 10 is a diagram illustrating a configuration of a second example of a power conversion device. [Figure 5] FIG. 10 is a diagram showing a third example of the layout structure of the line capacitors and the ground capacitors. [Figure 6] FIG. 10 is a diagram showing a fourth example of the arrangement structure of the line capacitors and the ground capacitors. [Figure 7] FIG. 10 is a diagram illustrating a configuration of a third example of a power conversion device. [Figure 8] FIG. 10 is a diagram illustrating a configuration of a fourth example of a power conversion device. [Figure 9] FIG. 10 is a diagram illustrating a configuration of a fifth example of a power conversion device. [Figure 10] FIG. 10 is a diagram illustrating a configuration of a sixth example of a power conversion device. [Figure 11] FIG. 10 is a diagram illustrating a configuration of a seventh example of a power conversion device. [Figure 12] FIG. 10 is a diagram illustrating the configuration of an eighth example of a power conversion device. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment will be described with reference to the drawings.

[0013] [First example of a power conversion device] The configuration of a first example of a power conversion device 1 according to this embodiment will be described with reference to FIG.

[0014] FIG. 1 is a diagram showing the configuration of a first example of a power conversion device 1. As shown in FIG.

[0015] 1, the power conversion device 1 includes an input unit 10, a ground terminal 15, a rectifier circuit 20, a DC line 30, an inverter circuit 40, an output unit 50, a ground terminal 55, a smoothing capacitor 60, and a line capacitor 65. The power conversion device 1 also includes a pair of DC reactors 70P, 70N, a line capacitor 80, and a line capacitor 85.

[0016] The power conversion device 1 converts three-phase AC (i.e., AC having R, S, and T phases) supplied from an external power source into three-phase AC (i.e., AC having U, V, and W phases) of a predetermined voltage and frequency, and outputs the converted AC from the output unit 50. This enables the power conversion device 1 to drive a load device connected to the output unit 50. The external power source is, for example, a commercial power source. The load device is, for example, a synchronous motor or an induction motor.

[0017] The input unit 10 is connected to a three-phase AC external power supply, whereby three-phase AC (AC of R phase, S phase, and T phase) is input from the external power supply to the input unit 10. The input unit 10 includes input terminals 10R, 10S, and 10T of the external power supply.

[0018] The input terminal 10R is electrically connected to an R-phase terminal of an external power supply outside the power conversion device 1. The input terminal 10S is electrically connected to an S-phase terminal of an external power supply outside the power conversion device 1. The input terminal 10T is electrically connected to a T-phase terminal of an external power supply outside the power conversion device 1.

[0019] The ground terminal 15 is used to ground the ground GND of the power conversion device 1. The ground GND is a conductive part corresponding to the reference potential of the power conversion device 1. The conductive part is, for example, a dedicated line for the reference potential that is connected to the housing of the power conversion device 1 or the housing. One end of a grounding electric path is connected to the ground terminal 15, and the other end of the grounding electric path is grounded. Inside the power conversion device 1, one end of the ground GND is connected to the ground terminal 15.

[0020] The rectifier circuit 20 converts three-phase AC (that is, AC of R phase, S phase, and T phase) input from an external power supply through the input unit 10 into DC and outputs it to the DC line 30.

[0021] For example, as shown in FIG. 1, the rectifier circuit 20 includes a diode bridge circuit configured with six rectifier diodes RD.

[0022] The DC line 30 electrically connects the rectifier circuit 20 and the inverter circuit 40, and supplies the DC output from the rectifier circuit 20 to the inverter circuit 40. In addition, the DC line 30 receives regenerated power from a load device via the inverter circuit 40. The DC line 30 includes a positive line 30P on the positive side (i.e., high-voltage side) and a negative line 30N on the negative side (i.e., low-voltage side).

[0023] The positive line 30P connects the positive output of the rectifier circuit 20 and the positive input of the inverter circuit 40. The negative line 30N connects the positive output of the rectifier circuit 20 and the positive input of the inverter circuit 40.

[0024] The inverter circuit 40 converts the DC of the DC line 30 into three-phase AC (i.e., AC of U phase, V phase, and W phase) of a predetermined voltage and frequency by the switching operation of a semiconductor switch (also called a "switching element") SW, and outputs it to the output section 50.

[0025] The semiconductor switch SW is primarily made of silicon (Si), for example. Alternatively, the semiconductor switch SW may be primarily made of a wide bandgap semiconductor material, such as silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), or carbon (diamond (C)).

[0026] For example, as shown in FIG. 1, the inverter circuit 40 is configured by a full-bridge circuit including six semiconductor switches SW. Specifically, three sets of series-connected bodies (i.e., switch legs) of two semiconductor switches SW corresponding to upper and lower arms are provided, and the three sets of switch legs are connected in parallel between the positive line 30P and the negative line 30N. Then, U-phase, V-phase, and W-phase terminals are drawn from midpoints of the upper and lower arms of the three sets of switch legs and connected to the output unit 50. Furthermore, for example, as shown in FIG. 1, the inverter circuit 40 includes freewheeling diodes FD connected in parallel to each semiconductor switch SW, with the forward direction directed from the negative line 30N side to the positive line 30P side.

[0027] The output unit 50 outputs the three-phase AC power output from the inverter circuit 40 to a load device. The output unit 50 includes output terminals 50U, 50V, and 50W.

[0028] The output terminal 50U is electrically connected to the U-phase output of the inverter circuit 40 inside the power conversion device 1, and is electrically connected to the U-phase terminal of the load device outside the power conversion device 1. The output terminal 50V is electrically connected to the V The output terminal 50W is electrically connected to the W-phase output of the inverter circuit 40 inside the power conversion device 1, and is electrically connected to the W-phase terminal of the load device outside the power conversion device 1. The output terminal 50W is electrically connected to the W-phase output of the inverter circuit 40 inside the power conversion device 1, and is electrically connected to the W-phase terminal of the load device outside the power conversion device 1.

[0029] The ground terminal 55 is electrically connected to a conductive part (for example, a housing) corresponding to the reference potential of the load device. This allows the power conversion device 1 to ground the conductive part corresponding to the reference potential of the load device via a grounding electric path connected to the ground GND and the ground terminal 15.

[0030] The smoothing capacitor 60 is provided to electrically connect the positive line 30P and the negative line 30N. The smoothing capacitor 60 is, for example, an electrolytic capacitor. The smoothing capacitor 60 suppresses and smoothes pulsations in the DC output from the rectifier circuit 20 and the DC regenerated from the inverter circuit 40 while repeatedly charging and discharging as appropriate.

[0031] For example, as shown in Fig. 1, one smoothing capacitor 60 is provided. Alternatively, a plurality of smoothing capacitors 60 may be provided. When a plurality of smoothing capacitors 60 is provided, the plurality of smoothing capacitors 60 may be connected in parallel or in series between the positive line 30P and the negative line 30N. Alternatively, the plurality of smoothing capacitors 60 may be configured such that a series connection of two or more smoothing capacitors 60 is connected in parallel between the positive line 30P and the negative line 30N.

[0032] The line capacitor 65 is provided in the DC line 30 between the smoothing capacitor 60 and the inverter circuit 40 so as to electrically connect between the positive line 30P and the negative line 30N.

[0033] For example, as shown in Fig. 1, one line capacitor 65 is provided. Alternatively, a plurality of line capacitors 65 may be provided. When a plurality of line capacitors 65 is provided, the plurality of line capacitors 65 may be connected in parallel or in series between the positive line 30P and the negative line 30N. Alternatively, the plurality of line capacitors 65 may be configured such that a series connection of two or more line capacitors 65 is connected in parallel between the positive line 30P and the negative line 30N.

[0034] A pair of DC reactors 70P and 70N are provided on the DC line 30 in order to reduce common mode noise on the DC line 30.

[0035] The DC reactor 70P is provided on the positive line 30P between the rectifier circuit 20 and the smoothing capacitor 60. The DC reactor 70N is provided on the negative line 30N between the rectifier circuit 20 and the smoothing capacitor 60.

[0036] The line capacitor 80 is provided to electrically connect the end of the DC reactor 70P on the inverter circuit 40 side and the end of the DC reactor 70N on the inverter circuit 40 side. This makes it possible to suppress imbalance (potential difference) between the respective ends of the pair of DC reactors 70P, 70N on the inverter circuit 40 side when high-frequency common-mode noise currents (hereinafter referred to as "common-mode currents") flow through the positive line 30P and the negative line 30N.

[0037] For example, as shown in Fig. 1, one line capacitor 80 is provided. Alternatively, a plurality of line capacitors 80 may be provided. When a plurality of line capacitors 80 is provided, the plurality of line capacitors 80 may be connected in parallel or in series between an end of the DC reactor 70P on the inverter circuit 40 side and an end of the DC reactor 70N on the inverter circuit 40 side. Alternatively, the plurality of line capacitors 80 may be configured such that a series connection of two or more line capacitors 80 is connected in parallel between an end of the DC reactor 70P on the inverter circuit 40 side and an end of the DC reactor 70N on the inverter circuit 40 side.

[0038] The earth capacitor 85 is provided to electrically connect the end of the DC reactor 70N on the inverter circuit 40 side to the ground GND.

[0039] 1, for example, one earth capacitor 85 is provided. Alternatively, a plurality of earth capacitors 85 may be provided. When a plurality of earth capacitors 85 is provided, the plurality of earth capacitors 85 may be connected in parallel or in series between the end of the DC reactor 70N on the inverter circuit 40 side and ground GND. Alternatively, the plurality of earth capacitors 85 may be configured such that a series connection of two or more earth capacitors 85 is connected in parallel between the end of the DC reactor 70N on the inverter circuit 40 side and ground GND.

[0040] As shown in FIG. 1, a parasitic capacitance (also called "floating capacitance") C mp ,C mn ,C mo exists.

[0041] Parasitic capacitance C mp is the parasitic capacitance between the positive side (i.e., high voltage side) input of the inverter circuit 40 and the ground GND. mn is the parasitic capacitance between the negative (i.e., low-voltage) input of the inverter circuit 40 and the ground GND.mo is the parasitic capacitance between the output of the inverter circuit 40 and the ground GND.

[0042] Furthermore, the parasitic capacitance C mo is the combined capacitance of the parasitic capacitances between the output parts of the U phase, V phase, and W phase of the inverter circuit 40 and the ground GND, and for convenience, only the parasitic capacitance between the output part of the V phase and the ground GND is depicted in FIG.

[0043] Hereinafter, the total parasitic capacitance between the inverter circuit 40 and the ground GND, that is, the parasitic capacitance C mp ,C mn ,C mo The combined capacitance of these is called the "parasitic capacitance C m "

[0044] As shown in FIG. 1, a parasitic capacitance C rp ,C rn exists.

[0045] A high-frequency common mode current generated in response to the switching operation of the semiconductor switch SW in the inverter circuit 40 flows through the parasitic capacitance C m The DC reactors 70P and 70N have a relatively large parasitic capacitance C rp ,C rn Therefore, the high frequency common mode current flowing out from the inverter circuit 40 is transmitted through the parasitic capacitance C m , and the parasitic capacitance C on the DC reactor 70P, 70N side rp ,C rn This may result in an increase in high-frequency radiation noise, as a result of a portion of the high-frequency common-mode current flowing out from the input section 10 and the ground terminal 15 to the outside, or a conductive section (such as a housing) in the common-mode circulation path acting as a radiation source to generate radiation noise.

[0046] In contrast, in this example, when a high-frequency common mode current circulates, the ends of the DC reactors 70P, 70N on the inverter circuit 40 side are short-circuited at high frequencies due to the action of the line capacitor 80. Therefore, imbalance between the positive line 30P and the negative line 30N when a high-frequency common mode current circulates is suppressed, and as a result, it is possible to suppress a situation in which high-frequency noise current flows out from the input unit 10 side and the ground terminal 15 side to the outside.

[0047] In this example, a path is formed in which the common mode current flowing from the inverter circuit 40 to the ground GND flows back to the inverter circuit 40 via the earth capacitor 85. This allows the action of the earth capacitor 85 to change the resonant frequency of the circulation path of the high frequency common mode current. For this reason, for example, when the capacitance C 85 By appropriately setting the resonant frequency of the circulating path of the high-frequency noise current, it is possible to adjust the resonant frequency to be relatively low relative to the frequency band where radiated noise becomes a problem (for example, a frequency band of 30 MHz or higher). This makes it possible to suppress radiated noise that originates from the conductive part of the circulating path as a radiation source.

[0048] [First example of how to determine circuit constants] Continuing with reference to FIG. 1, a method for determining the circuit constants in the first example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0049] For example, the parasitic capacitance C m , and parasitic capacitance C rp , parasitic capacitance C rn The resonant frequency fr of the circulating path of the high frequency common mode current through the earth capacitor 85 is determined by the parasitic inductance L of the DC line 30 (also called "wiring inductance"). pn Using the above, it is expressed by the following equations (1) to (3).

[0050]

number

[0051] The parasitic inductance L of the DC line 30 pn is the parasitic inductance L of the positive line 30P p and the parasitic inductance L of the negative line 30N n The parasitic inductance L pn is expressed by the following equation (4).

[0052]

number

[0053] In addition, the parasitic capacitance C m , and parasitic capacitance C rp , parasitic capacitance C rn The resonant frequency fr of the circulating path of the high frequency common mode current through the earth capacitor 85 is determined by the parasitic inductance L of the DC line 30. pn In addition, the parasitic inductance L e may be expressed by the following equation (5).

[0054]

number

[0055] For example, the capacitance C of the earth capacitor 85 85 is determined so that the resonance frequency fr is equal to or less than the lower limit value fmin of the high frequency band where radiation noise becomes a problem.

[0056] The lower limit fmin is set to a high frequency band where radiation noise becomes a problem, specifically, a frequency of 1 MHz or higher. For example, the lower limit fmin is set to 30 MHz, which is the lower limit of the regulated band in the IEC (International Electrotechnical Commission) standard on EMC (Electromagnetic Compatibility).

[0057] As shown in equation (2), the capacitance C of the earth capacitor 85 85 is the parasitic capacitance C rp ,C rn The larger the parasitic capacitance C in the total capacitance C of the circulation path, rp ,C rn Therefore, as shown in the formula (1) or (5) and the formula (2), for example, the capacitance C of the earth capacitor 85 can be increased. 85 is the parasitic capacitance C rp ,C rn By setting the resonant frequency fr to be greater than each of the above, the resonant frequency fr of the circulation path can be effectively lowered, thereby suppressing radiation noise originating from the conductive part of the circulation path as a radiation source.

[0058] Furthermore, as shown in equation (2), the capacitance C of the earth capacitor 85 85 is the parasitic capacitance C rp ,C rn ,C m If the sum of the numerator and denominator is sufficiently larger than the capacitance of the earth capacitor C 85 As a result, the total capacitance C of the circulation path can be approximated by the parasitic capacitance C m In other words, the capacitance C of the earth capacitor 85 85 is the parasitic capacitance C rp ,C rn ,C m When the value of the resonant frequency fr is increased to a certain extent, the effect of reducing the resonant frequency fr is saturated.

[0059] Considering the above, the capacitance C of the earth capacitor 85 85is set in the range of 100 pF to 1000 pF, for example.

[0060] [First example of the layout of line capacitors and ground capacitors] A first example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 2 in addition to FIG.

[0061] FIG. 2 is a diagram showing a first example of the layout structure of the line capacitors 80 and the ground capacitors 85. In FIG.

[0062] As shown in FIG. 2, in this example, the DC reactors 70P and 70N are fixed to a housing corresponding to the ground GND in the power conversion device 1.

[0063] The DC reactor 70P includes a magnetic core 70PC made of a magnetic material and a winding 70PW formed by winding an electric wire around the magnetic core 70PC. The magnetic material is, for example, ferrite or carbonyl iron.

[0064] The magnetic core 70PC is fixed to the housing of the power converter 1 by a bolt 70PB.

[0065] Both ends of the electric wire of the winding 70PW are drawn out from the winding 70PW as lead wires 70PL1 and 70PL2.

[0066] The lead wire 70PL1 is connected to the positive line 30P on the rectifier circuit 20 side, and the lead wire 70PL2 is connected to the positive line 30P on the inverter circuit 40 side.

[0067] The DC reactor 70N includes a magnetic core 70NC made of a magnetic material and a winding 70NW formed by winding an electric wire around the magnetic core 70PC, such as ferrite or carbonyl iron.

[0068] The magnetic core 70NC is fixed to the housing of the power converter 1 by a bolt 70NB.

[0069] Both ends of the electric wire of the winding 70NW are drawn out from the winding 70NW as lead wires 70NL1 and 70NL2.

[0070] The lead-out line 70NL1 is connected to the negative line 30N on the rectifier circuit 20 side, and the lead-out line 70NL2 is connected to the negative line 30N on the inverter circuit 40 side.

[0071] The line capacitor 80 has two terminals 80T1 and 80T2, one terminal 80T1 is electrically connected to the lead-out wire 70PL2, and the other terminal 80T2 is electrically connected to the lead-out wire 70NL2. For example, the terminals 80T1 and 80T2 are connected to the lead-out wires 70PL2 and 70NL2, respectively, by soldering, using a sleeve, or the like.

[0072] The earth capacitor 85 has two terminals 85T1 and 85T2. One terminal 85T1 is connected to the lead wire 70NL2, and the other terminal 85T2 is connected directly or indirectly to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 70NL2 by soldering, using a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 70NC by the bolt 70NB. As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 70NB.

[0073] The connection point between terminal 80T1 of line capacitor 80 and lead wire 70PL2 is preferably as close as possible to winding 70PW. Also, the connection points between terminal 80T2 of line capacitor 80 and lead wire 70NL2 of terminal 85T1 of earth capacitor 85 are preferably as close as possible to winding 70NW.

[0074] It is preferable that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70NL2 are as close as possible to each other. For example, as shown in Fig. 2, the terminal 80T2 and the terminal 85T1 are connected to the lead wire 70NL2 so that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70NL2 coincide with each other.

[0075] [Second example of the layout of line capacitors and ground capacitors] A second example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 3 in addition to FIG.

[0076] Fig. 3 is a diagram showing a second example of the arrangement structure of line capacitors 80 and ground capacitors 85. In the following, this example may be described using the XY coordinates defined in Fig. 3, and the positive X-axis direction and negative X-axis direction may be collectively referred to as the "X-axis direction," and the positive Y-axis direction and negative Y-axis direction may be collectively referred to as the "Y-axis direction."

[0077] 3, only the regions 30BRP and 30BRN on the substrate 30B where the DC reactors 70P and 70N are arranged, respectively, are depicted, and the DC reactors 70P and 70N themselves are not depicted.

[0078] 3, in this example, DC reactors 70P and 70N are mounted on a substrate 30B. The substrate 30B has, for example, a rectangular shape in plan view that is defined by two sides extending in the X-axis direction and the Y-axis direction.

[0079] The substrate 30B includes wiring patterns 30PP1, 30PP2, 30NP1, 30NP2, and 30GP.

[0080] The wiring pattern 30PP1 corresponds to a part of the positive line 30P, and is arranged on the substrate 30B so as to electrically connect the positive-side (i.e., high-voltage side) output portion of the rectifier circuit 20 and one terminal of the DC reactor 70P. In this example, the wiring pattern 30PP1 is arranged on one surface of the substrate 30B so as to extend in the X-axis direction. The end of the wiring pattern 30PP1 facing the negative X-axis is connected to the positive-side (i.e., high-voltage side) output portion of the rectifier circuit 20, and a land LDP1 for connecting one terminal of the DC reactor 70P is provided at the end of the wiring pattern 30PP1 facing the positive X-axis direction.

[0081] The wiring pattern 30PP2 corresponds to a portion of the positive line 30P and is disposed on the substrate 30B so as to electrically connect the other terminal of the DC reactor 70P and the positive-side (i.e., high-voltage) input of the inverter circuit 40. In this example, the wiring pattern 30PP2 is disposed on one surface of the substrate 30B so as to extend in the X-axis direction. The negative X-axis end of the wiring pattern 30PP2 is disposed to face the positive X-axis end of the wiring pattern 30PP1 in the X-axis direction, and a region 30BRP is provided between the wiring patterns 30PP1 and 30PP2 on the one surface of the substrate 30B. The negative X-axis end of the wiring pattern 30PP2 is provided with a land LDP2 for connecting the other terminal of the DC reactor 70P, and the positive X-axis end of the wiring pattern 30PP2 is connected to the positive X-axis (i.e., high-voltage) input of the inverter circuit 40.

[0082] The wiring pattern 30NP1 corresponds to a part of the negative line 30N and is arranged on the substrate 30B so as to electrically connect the negative-side (i.e., low-voltage side) output portion of the rectifier circuit 20 and one terminal of the DC reactor 70N. In this example, the wiring pattern 30NP1 is arranged on one surface of the substrate 30B so as to extend in the X-axis direction at a position spaced a predetermined distance in the negative Y-axis direction from the wiring pattern 30PP1. The end of the wiring pattern 30NP1 in the negative X-axis direction is connected to the negative-side (i.e., low-voltage side) output portion of the rectifier circuit 20, and a land LDN1 for connecting one terminal of the DC reactor 70N is provided at the end of the wiring pattern 30NP1 in the positive X-axis direction.

[0083] The wiring pattern 30NP2 corresponds to a portion of the negative line 30N and is disposed on the substrate 30B so as to connect the other terminal of the DC reactor 70N and the negative-side (i.e., low-voltage side) input of the inverter circuit 40. In this example, the wiring pattern 30NP2 is disposed on one surface of the substrate 30B so as to extend in the X-axis direction at a position spaced a predetermined distance in the negative Y-axis direction from the wiring pattern 30PP2. The end of the wiring pattern 30NP2 in the negative X-axis direction is disposed so as to face the end of the wiring pattern 30NP1 in the positive X-axis direction in the X-axis direction, and a region 30BRN is provided between the wiring patterns 30NP1 and 30NP2 on one surface of the substrate 30B. The end of the wiring pattern 30NP2 in the negative X-axis direction is provided with a land LDN2 for connecting the other terminal of the DC reactor 70P, and the end of the wiring pattern 30NP2 in the positive X-axis direction is connected to the negative-side (i.e., low-voltage side) input of the inverter circuit 40.

[0084] Wiring pattern 30PP3 is disposed on substrate 30B integrally with wiring pattern 30PP2 so as to connect one terminal of line capacitor 80 and a terminal of DC reactor 70P on the inverter circuit 40 side. In this example, wiring pattern 30PP3 is disposed on one surface of substrate 30B so as to protrude in the negative Y-axis direction from a point moved a predetermined distance in the positive X-axis direction from one end of wiring pattern 30PP2 in the negative X-axis direction.

[0085] Wiring pattern 30NP3 is disposed on substrate 30B integrally with wiring pattern 30NP2 so as to connect the other terminal of line capacitor 80 and the terminal of DC reactor 70N on the inverter circuit 40 side. In this example, wiring pattern 30NP3 is disposed on one surface of substrate 30B so as to protrude in the positive direction of the Y axis from the same position on wiring pattern 30NP2 in the X axis direction as wiring pattern 30PP3. As a result, wiring patterns 30PP3 and 30NP3 are disposed so that their tips face each other in the Y axis direction.

[0086] The wiring pattern 30NP4 is disposed on the substrate 30B integrally with the wiring pattern 30NP2 so as to connect between the inverter circuit 40 side terminal of the DC reactor 70N and one terminal of the earth capacitor 85. In this example, the wiring pattern 30NP4 is disposed on one surface of the substrate 30B so as to protrude in the negative Y-axis direction from the same position on the wiring pattern 30NP2 as the wiring pattern 30PP3 in the X-axis direction.

[0087] The wiring pattern 30GP corresponds to a part or all of the ground GND. In this example, the wiring pattern 30GP is disposed at a position facing the tip of the wiring pattern 30NP4 in the Y-axis direction at a relatively short distance.

[0088] One terminal of the line capacitor 80 is connected to the wiring pattern 30PP3, and the other terminal is connected to the wiring pattern 30NP3. In this example, one terminal of the line capacitor 80 is connected to the tip of the wiring pattern 30PP3 in the Y-axis direction, and the other terminal is connected to the tip of the wiring pattern 30NP3 in the Y-axis direction, and the line capacitor 80 is arranged to bridge between the wiring patterns 30PP3 and 30NP3 in the Y-axis direction.

[0089] One terminal of the ground capacitor 85 is connected to the wiring pattern 30NP4, and the other terminal is connected to the wiring pattern 30GP. In this example, one terminal of the ground capacitor 85 is connected to the tip of the wiring pattern 30NP4 in the Y-axis direction, and the other terminal is connected to the end of the wiring pattern 30GP in the negative X-axis direction, and the ground capacitor 85 is disposed so as to bridge between the wiring patterns 30NP4 and 30GP in the Y-axis direction.

[0090] It is preferable that the land LDP2 and the portion of the wiring pattern 30PP2 corresponding to the base end of the wiring pattern 30PP3 are set as close as possible to each other. It is also preferable that the land LDN2 and the portions of the wiring pattern 30NP2 corresponding to the base ends of the wiring patterns 30NP3 and 30NP4 are set as close as possible to each other.

[0091] It is preferable that the base ends of the wiring patterns 30NP3 and 30NP4 in the wiring pattern 30NP2 are located as close as possible to each other. For example, as shown in Fig. 3, the base ends of the wiring patterns 30NP3 and 30NP4 in the wiring pattern 30NP2 are located at the same position in the X-axis direction.

[0092] [Second example of power conversion device] A configuration of a second example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0093] In the following, components that are the same as or correspond to the first example of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first example described above, and explanations of content that is the same as or corresponds to the first example described above may be omitted.

[0094] FIG. 4 is a diagram showing the configuration of a second example of the power conversion device 1. In FIG.

[0095] The power conversion device 1 according to this example differs from the first example described above mainly in that a common mode choke coil 75 is provided instead of the DC reactors 70P and 70N.

[0096] The common mode choke coil 75 is disposed between the rectifier circuit 20 and the line capacitor 80 on the DC line 30. The common mode choke coil 75 includes a coil 75P provided for the positive line 30P and a coil 75N provided for the negative line 30N.

[0097] One end of the coil 75P is electrically connected to the positive line 30P on the rectifier circuit 20 side, and the other end is electrically connected to the positive line 30P on the inverter circuit 40 side. One end of the coil 75N is electrically connected to the negative line 30N on the rectifier circuit 20 side, and the other end is electrically connected to the negative line 30N on the inverter circuit 40 side.

[0098] Coils 75P and 75N have wires wound in opposite directions around the same magnetic core (for example, magnetic core 75C, described below). This allows common mode choke coil 75 to act as an inductor to suppress the common mode current flowing through positive line 30P and negative line 30N. The magnetic core is made of a magnetic material such as ferrite or carbonyl iron.

[0099] The line capacitor 80 is provided between the end of the coil 75P on the inverter circuit 40 side and the end of the coil 75N on the inverter circuit 40 side, and electrically connects them together. This makes it possible to suppress imbalance (potential difference) between the ends of the coils 75P and 75N on the inverter circuit 40 side when a high-frequency common-mode current flows through the positive line 30P and the negative line 30N.

[0100] The earth capacitor 85 is provided between the end of the coil 75N on the inverter circuit 40 side and the ground GND, with the end electrically connected to the ground GND.

[0101] As shown in FIG. 4, a parasitic capacitance C mp ,C mn ,C mo In other words, there is a parasitic capacitance C mp ,C mn ,C mo The parasitic capacitance C corresponds to the combined capacitance of m exists.

[0102] In FIG. 4, as in the case of FIG. 1 described above, for convenience, only the parasitic capacitance between the V-phase output section and the ground GND is depicted.

[0103] As shown in FIG. 4, there is a parasitic capacitance C cp ,C cn exists.

[0104] A high-frequency common mode current generated in response to the switching operation of the semiconductor switch SW in the inverter circuit 40 flows through the parasitic capacitance C m The coils 75P and 75N have a relatively large parasitic capacitance C cp ,C cn Therefore, the high frequency common mode current flowing out from the inverter circuit 40 is transmitted through the parasitic capacitance C m , and the parasitic capacitance C on the DC reactor 70P, 70N side cp ,C cn This may result in an increase in high-frequency radiation noise due to a portion of the high-frequency common-mode current flowing out from the input section 10 and the ground terminal 15 to the outside, or radiation noise being generated from the conductive portion of the common-mode circulation path as a radiation source.

[0105] In contrast, in this example, as in the first example described above, when a high-frequency common mode current circulates, the ends of the coils 75P, 75N on the inverter circuit 40 side are short-circuited at high frequencies due to the action of the line capacitor 80. This suppresses imbalance between the positive line 30P and the negative line 30N when the high-frequency common mode current circulates, and as a result, it is possible to suppress a situation in which the high-frequency common mode current flows out from the input unit 10 side and the ground terminal 15 side to the outside.

[0106] In this example, similarly to the first example described above, the resonance frequency of the circulating path of the high-frequency common mode current can be changed by the action of the earth capacitor 85. Therefore, for example, the capacitance C 85 By appropriately setting the resonant frequency of the circulating path of the high-frequency noise current, it is possible to adjust the resonant frequency to be relatively low relative to the frequency band where radiated noise becomes a problem (for example, a frequency band of 30 MHz or higher). This makes it possible to suppress radiated noise that originates from the conductive part of the circulating path as a radiation source.

[0107] [Second example of how to determine circuit constants] Continuing with reference to Fig. 4, a method for determining the circuit constants in the second example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0108] The following description will focus on the differences from the first example of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first example may be omitted.

[0109] The capacitance C of the earth capacitor 85 in the second example of the power conversion device 1 85 can be determined in the same way as in the first example above.

[0110] Specifically, "DC reactor 70P, 70N" and "parasitic capacitance C rp ,C rn " is "Coil 75P, 75N", "Parasitic capacitance C cp ,C cn ", the capacitance C of the earth capacitor 85 in the first example of the power conversion device 1 described above is 85 The explanation of the method for determining the value of the variable can be used.

[0111] [Third example of the layout of line capacitors and ground capacitors] A third example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 5 in addition to FIG.

[0112] In the following, the same symbols will be used for configurations that are the same as or correspond to the first example of the arrangement structure described above, and the explanation will focus on the parts that are different from the first example described above, and explanations of the parts that are the same as or correspond to the first example described above may be omitted.

[0113] FIG. 5 is a diagram showing a third example of the layout structure of the line capacitors 80 and the ground capacitors 85. In FIG.

[0114] As shown in FIG. 5, in this example, the common mode choke coil 75 is fixed to a housing corresponding to the ground GND in the power conversion device 1.

[0115] Common mode choke coil 75 includes a magnetic core 75C formed of a magnetic material, and coils 75P and 75N formed by winding an electric wire around magnetic core 75C.

[0116] The magnetic core 75C is fixed to the housing of the power converter 1 by a bolt 75B.

[0117] Both ends of the electric wire of the coil 75P are drawn out from the coil 75P as lead wires 75PL1 and 75PL2.

[0118] The lead wire 75PL1 is connected to the positive line 30P on the rectifier circuit 20 side, and the lead wire 75PL2 is connected to the positive line 30P on the inverter circuit 40 side.

[0119] Both ends of the electric wire of the coil 75N are drawn out from the coil 75N as lead wires 75NL1 and 75NL2.

[0120] The lead-out line 75NL1 is connected to the negative line 30N on the rectifier circuit 20 side, and the lead-out line 75NL2 is connected to the negative line 30N on the inverter circuit 40 side.

[0121] The line capacitor 80 has two terminals 80T1 and 80T2, one terminal 80T1 is electrically connected to the lead wire 75PL2, and the other terminal 80T2 is electrically connected to the lead wire 75NL2. For example, the terminals 80T1 and 80T2 are connected to the lead wires 75PL2 and 75NL2, respectively, by soldering, using a sleeve, or the like.

[0122] The earth capacitor 85 has two terminals 85T1 and 85T2. One terminal 85T1 is connected to the lead wire 75NL2, and the other terminal 85T2 is connected directly or indirectly to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 75NL2 by soldering, using a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 75C by a bolt 75B. As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 75B.

[0123] It is preferable that the connection point between terminal 80T1 of line capacitor 80 and lead wire 75PL2 be as close as possible to coil 75P. It is also preferable that the connection points between terminal 80T2 of line capacitor 80 and lead wire 75NL2 of terminal 85T1 of earth capacitor 85 are as close as possible to coil 75P.

[0124] It is preferable that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75NL2 are as close as possible. For example, as shown in Fig. 5, the terminal 80T2 and the terminal 85T1 are connected to the lead wire 75NL2 so that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75NL2 coincide with each other.

[0125] [Fourth example of the layout of line capacitors and ground capacitors] A fourth example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 6 in addition to FIG.

[0126] Hereinafter, in this example, the same symbols are used for components that are the same as or correspond to the second example of the arrangement structure described above, and the explanation will focus on the parts that are different from the second example of the arrangement structure described above, and explanations of the parts that are the same as or correspond to the second example of the arrangement structure described above may be omitted.

[0127] As shown in FIG. 6, this example differs from the second example of the arrangement structure described above mainly in that the regions 30BRP and 30BRN in which the DC reactors 70P and 70N are respectively arranged are replaced with a region 30BC in which the common mode choke coil 75 is arranged.

[0128] 6, only the region 30BC of the substrate 30B where the common mode choke coil 75 is arranged is depicted, and the common mode choke coil 75 itself is omitted from the drawing.

[0129] 6, in this example, a common mode choke coil 75 is mounted on a substrate 30B. In this example, a region 30BC on the substrate 30B where the common mode choke coil 75 is mounted is set as a region connecting the regions 30BRP and 30BRN in the second example of the arrangement structure described above.

[0130] The wiring pattern 30PP1 corresponds to a part of the positive line 30P, and is connected to the substrate 30B so as to electrically connect the positive-side (i.e., high-voltage side) output of the rectifier circuit 20 and one terminal of the coil 75P. In this example, the end of the wiring pattern 30PP1 in the negative X-axis direction is connected to the positive-side (i.e., high-voltage side) output of the rectifier circuit 20, and a land LDP1 for connecting one terminal of the coil 75P is provided at the end of the wiring pattern 30PP1 in the positive X-axis direction.

[0131] The wiring pattern 30PP2 corresponds to a portion of the positive line 30P and is arranged on the substrate 30B so as to electrically connect the other terminal of the coil 75P and the positive-side (i.e., high-voltage) input of the inverter circuit 40. In this example, the end of the wiring pattern 30PP2 in the negative X-axis direction is arranged to face the end of the wiring pattern 30PP1 in the positive X-axis direction in the X-axis direction, and a region 30BC is provided between the wiring patterns 30PP1 and 30PP2 on one surface of the substrate 30B. A land LDP2 for connecting the other terminal of the coil 75P is provided at the end of the wiring pattern 30PP2 in the negative X-axis direction, and the end of the wiring pattern 30PP2 in the positive X-axis direction is connected to the positive-side (i.e., high-voltage) input of the inverter circuit 40.

[0132] The wiring pattern 30NP1 corresponds to a part of the negative line 30N, and is arranged on the substrate 30B so as to electrically connect the negative-side (i.e., low-voltage side) output part of the rectifier circuit 20 and one terminal of the coil 75N. In this example, the end of the wiring pattern 30NP1 in the negative X-axis direction is connected to the negative-side (i.e., low-voltage side) output part of the rectifier circuit 20, and a land LDN1 for connecting one terminal of the coil 75N is provided at the end of the wiring pattern 30NP1 in the positive X-axis direction.

[0133] The wiring pattern 30NP2 corresponds to a portion of the negative line 30N and is arranged on the substrate 30B so as to connect the other terminal of the coil 75N and the negative-side (i.e., low-voltage side) input of the inverter circuit 40. In this example, the end of the wiring pattern 30NP2 in the negative X-axis direction is arranged to face the end of the wiring pattern 30NP1 in the positive X-axis direction in the X-axis direction, and a region 30BC is provided between the wiring patterns 30NP1 and 30NP2 on one surface of the substrate 30B. A land LDN2 for connecting the other terminal of the coil 75P is provided at the end of the wiring pattern 30NP2 in the negative X-axis direction, and the end of the wiring pattern 30NP2 in the positive X-axis direction is connected to the negative-side (i.e., low-voltage side) input of the inverter circuit 40.

[0134] As in the second example of the arrangement structure described above, one terminal of the line capacitor 80 is connected to the wiring pattern 30PP3, and the other terminal is connected to the wiring pattern 30NP3.

[0135] As in the second example of the arrangement structure described above, one terminal of the earth capacitor 85 is connected to the wiring pattern 30NP4, and the other terminal is connected to the wiring pattern 30GP.

[0136] [Third example of power conversion device] A configuration of a third example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0137] In the following, components that are the same as or correspond to those in the first and second examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first and second examples described above, and explanations of the same or corresponding parts as those in the first and second examples described above may be omitted.

[0138] FIG. 7 is a diagram illustrating a configuration of a third example of the power conversion device 1. In FIG.

[0139] The power conversion device 1 according to this example differs from the first example described above in that an earth capacitor 85 is provided to electrically connect the end of the DC reactor 70P on the inverter circuit 40 side to the ground GND. That is, in this example, compared to the first example described above, the connection destination of the earth capacitor 85 on the DC line 30 side is changed from the end of the DC reactor 70N on the negative line 30N on the inverter circuit 40 side to the end of the DC reactor 70P on the positive line 30P on the inverter circuit 40 side. Furthermore, the power conversion device 1 according to this example may be the same as the first example described above in other respects.

[0140] In this example, similar to the first example described above, the resonant frequency of the circulating path of the high-frequency common mode current can be changed by the action of earth capacitor 85. Therefore, the same actions and effects as those of the first example described above can be achieved.

[0141] [Third example of how to determine circuit constants] Continuing with reference to Fig. 7, a method for determining the circuit constants in the third example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0142] The following description will focus on the differences from the first and second examples of the method for determining circuit constants described above, and may omit descriptions of the same or corresponding parts as the first and second examples.

[0143] Parasitic capacitance C m , and parasitic capacitance C rp , parasitic capacitance C rnThe resonant frequency fr of the circulating path of the high-frequency common mode current through the line capacitor 80 and the ground capacitor 85 is expressed by equation (1) or equation (4) based on equations (2) to (4), as in the first example described above. This is because the line capacitor 80 can be regarded as being short-circuited at high frequencies.

[0144] Therefore, by using the same method as in the first example of the power conversion device 1 described above, the capacitance C 85 can be determined.

[0145] [5th ​​example of the layout of line capacitors and ground capacitors] A fifth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 2 in addition to FIG.

[0146] In the following, the same symbols will be used for configurations that are the same as or correspond to the first example of the arrangement structure described above, and the explanation will focus on the parts that are different from the first example described above, and explanations of the parts that are the same as or correspond to the first example described above may be omitted.

[0147] In this example, similarly to the first example (see FIG. 2) described above, the DC reactors 70P and 70N are fixed to a housing of the power conversion device 1 that corresponds to the ground GND.

[0148] In this example, the layout structure of the line capacitors 80 is the same as in the first example described above.

[0149] In this example, unlike the first example described above, the connection destination of the earth capacitor 85 on the DC line 30 side is disposed at the end of the DC reactor 70P on the inverter circuit 40 side. Therefore, one terminal 85T1 of the earth capacitor 85 is connected to the lead wire 70PL2, and the other terminal 85T2 is connected directly or indirectly to the housing of the power conversion device 1. For example, the terminal 85T1 is connected to the lead wire 70PL2 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 70PC by the bolt 70PB on the right side in FIG. 2 . As a result, the terminal 85T2 is electrically connected to the housing of the power conversion device 1 via the bolt 70PB.

[0150] The connection points between the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 and the lead wire 70PL2 are preferably as close as possible to the winding 70PW.

[0151] It is preferable that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70PL2 are as close as possible to each other. For example, the terminals 80T1 and 85T1 are connected to the lead wire 70PL2 so that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70PL2 coincide with each other.

[0152] [Example 6 of the layout of line capacitors and ground capacitors] A sixth example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 3 in addition to FIG.

[0153] Hereinafter, the same symbols will be used for the same or corresponding configurations as the second and fourth examples of the arrangement structure described above, and the explanation will focus on the parts that are different from the second and fourth examples described above, and explanations of the parts that are the same or corresponding to the second and fourth examples described above may be omitted.

[0154] In this example, similarly to the second example (see FIG. 3) described above, DC reactors 70P and 70N are mounted on the substrate 30B.

[0155] In this example, unlike the second example described above, the connection destination of the DC line 30 side of the earth capacitor 85 is arranged at the end of the DC reactor 70P on the inverter circuit 40 side.

[0156] For example, instead of wiring pattern 30NP4, an additional wiring pattern is provided that is disposed integrally with wiring pattern 30PP2 on one side of substrate 30B, and wiring pattern 30GP is moved to the vicinity of the additional wiring pattern. Specifically, for example, the additional wiring pattern is disposed on one side of substrate 30B so as to protrude in the positive Y-axis direction from the same position on wiring pattern 30PP2 as wiring pattern 30PP3 in the X-axis direction, and wiring pattern 30GP is disposed so as to face the additional wiring pattern in the positive Y-axis direction.

[0157] One terminal of the ground capacitor 85 is connected to the additional wiring pattern, and the other terminal is connected to the wiring pattern 30GP. For example, one terminal of the ground capacitor 85 is connected to the tip of the additional wiring pattern in the positive Y-axis direction, and the other terminal is connected to the end of the wiring pattern 30GP in the negative X-axis direction, which is arranged to extend in the X-axis direction. Thus, the ground capacitor 85 is arranged to bridge between the additional wiring pattern and the wiring pattern 30GP in the Y-axis direction.

[0158] It is preferable that the land LDP2 and the portions of the wiring pattern 30PP2 that correspond to the base ends of the wiring pattern 30PP3 and the additional wiring pattern are set as close as possible to each other.

[0159] In the wiring pattern 30PP2, it is preferable that the base ends of the wiring pattern 30PP3 and the additional wiring pattern are located as close as possible to each other. For example, in the wiring pattern 30PP2, the base ends of the wiring pattern 30PP3 and the additional wiring pattern are located at the same position in the X-axis direction.

[0160] [Fourth example of a power conversion device] With reference to FIG. 8, a configuration of a fourth example of the power conversion device 1 according to this embodiment will be described.

[0161] In the following, components that are the same as or correspond to those in the first to third examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first to third examples described above, and explanations of the same or corresponding content as the first to third examples described above may be omitted.

[0162] FIG. 8 is a diagram illustrating a configuration of a fourth example of the power conversion device 1. In FIG.

[0163] 8, the power conversion device 1 according to this embodiment differs from the first and third embodiments described above in that a line capacitor 80 and a ground capacitor 85 are electrically connected to ends of a pair of DC reactors 70P, 70N on the side of the rectifier circuit 20. In other respects, the power conversion device 1 according to this embodiment may be the same as the first and third embodiments described above.

[0164] The line capacitor 80 is provided to electrically connect the ends of the DC reactors 70P, 70N on the rectifier circuit 20 side to each other.

[0165] The earth capacitor 85 is provided to electrically connect the end of the DC reactor 70N on the rectifier circuit 20 side to the ground GND.

[0166] In this example, when a high-frequency common mode current circulates, the ends of the DC reactors 70P, 70N on the rectifier circuit 20 side are short-circuited at high frequencies due to the action of the line capacitor 80. This suppresses imbalance between the positive line 30P and the negative line 30N when a high-frequency common mode current circulates, and as a result, it is possible to suppress a situation in which a high-frequency noise current flows out from the input unit 10 side and the ground terminal 15 side to the outside.

[0167] Furthermore, in this example, similar to the first and third examples described above, the action of the earth capacitor 85 forms a path through which the common mode current flowing out from the inverter circuit 40 to the ground GND flows back to the inverter circuit 40 via the earth capacitor 85. This provides the same functions and effects as the first and third examples described above.

[0168] [Fourth example of how to determine circuit constants] Continuing with reference to Fig. 8, a method for determining the circuit constants in the fourth example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0169] The following description will focus on the differences from the first to third examples of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first to third examples described above may be omitted.

[0170] For example, for simplicity, assume that the positive line 30P and the negative line 30N are balanced, and that the respective parasitic inductances L of the positive line 30P and the negative line 30N are p ,L n , parasitic capacitance C rp ,C rn , and the parasitic capacitance EPC between both ends of each of the DC reactors 70P and 70N rp ,EPC rn Consider the case where the following equations (6) to (8) hold.

[0171]

number

[0172] In this case, the parasitic capacitance C m , and parasitic capacitance C rp , parasitic capacitance C rn The resonant frequency fr of the circulating path of the high frequency common mode current through the earth capacitor 85 is determined by the parasitic inductance L of the DC line 30. pn , the parasitic inductance L of the ground GND eand a parasitic capacitance EPC between both ends of the DC reactors 70P and 70N, the following equations (9) to (12) are used.

[0173]

number

[0174] Similarly to the first example (see equation (1)), the parasitic inductance L pn , and the parasitic inductance L of the ground GND e The resonance frequency fr may be evaluated by considering only the former of the above.

[0175] For example, as in the first and third examples described above, the capacitance C of the earth capacitor 85 85 is determined so that the resonance frequency fr is equal to or less than the lower limit value fmin of the high frequency band where radiation noise becomes a problem.

[0176] As shown in equations (6), (10), and (11), the capacitance C of the earth capacitor 85 85 is the parasitic capacitance C rp ,C rn The larger the parasitic capacitance C in the total capacitance C of the circulation path, rp ,C rn Therefore, as shown in equation (9), for example, the capacitance C of the earth capacitor 85 can be 85 is the parasitic capacitance C rp ,C rn By setting the resonant frequency fr to be greater than each of the above, the resonant frequency fr of the circulation path can be effectively lowered, thereby suppressing radiation noise originating from the conductive part of the circulation path as a radiation source.

[0177] In addition, the parasitic capacitance C r The capacitance C of the earth capacitor 85 is set to a value that can be ignored. 85 is sufficiently large, the total capacitance C of the circulation path is calculated by the parasitic capacitance C m ,EPC rp,EPC rn Therefore, the capacitance C of the earth capacitor 85 85 is the parasitic capacitance C rp ,C rn When the value of the resonant frequency fr is increased to a certain extent, the effect of reducing the resonant frequency fr is saturated.

[0178] Considering the above, the capacitance C of the earth capacitor 85 85 is set in the range of 100 pF to 1000 pF, for example.

[0179] [7th example of the layout of line capacitors and earth capacitors] A seventh example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 2 in addition to FIG.

[0180] Hereinafter, the same symbols will be used for the same or corresponding configurations as the first and fifth examples of the arrangement structure described above, and the explanation will focus on the parts that are different from the first and fifth examples described above, and explanations of the parts that are the same or corresponding to the first and fifth examples described above may be omitted.

[0181] In this example, similarly to the first example (see FIG. 2) described above, the DC reactors 70P and 70N are fixed to a housing of the power conversion device 1 that corresponds to the ground GND.

[0182] In this example, unlike the first and fifth examples described above, the line capacitor 80 is connected to the ends of the DC reactors 70P and 70N on the rectifier circuit 20 side. Therefore, one terminal 80T1 of the line capacitor 80 is electrically connected to the lead-out wire 70PL1, and the other terminal 80T2 is connected to the lead-out wire 70NL1. For example, the terminals 80T1 and 80T2 are connected to the lead-out wires 70PL1 and 70NL1, respectively, by soldering, using a sleeve, or the like.

[0183] Furthermore, in this example, unlike the first and fifth examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is disposed at the end of the DC reactor 70N on the rectifier circuit 20 side. Therefore, one terminal 85T1 of the earth capacitor 85 is electrically connected to the lead wire 70NL1, and the other terminal 85T2 is directly or indirectly connected to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 70NL1 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 70NC by the bolt 70NB on the left side in FIG. 2 . As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 via the bolt 70NB.

[0184] The connection point between terminal 80T1 of line capacitor 80 and lead wire 70PL1 is preferably as close as possible to winding 70PW. Also, the connection points between terminal 80T2 of line capacitor 80 and lead wire 70NL1 of terminal 85T1 of earth capacitor 85 are preferably as close as possible to winding 70NW.

[0185] It is preferable that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70NL1 are as close as possible to each other. For example, the terminal 80T2 and the terminal 85T1 are connected to the lead wire 70NL1 so that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70NL1 coincide with each other.

[0186] [Example 8 of the layout of line capacitors and ground capacitors] An eighth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 3 in addition to FIG.

[0187] Hereinafter, the same symbols will be used for the same or corresponding configurations as those in the second, fourth, and sixth examples of the arrangement structure described above, and the explanation will focus on the parts that differ from the second, fourth, and sixth examples described above, and explanations of the parts that are the same or corresponding to those in the second, fourth, and sixth examples described above may be omitted.

[0188] In this example, similarly to the second example (see FIG. 3) described above, DC reactors 70P and 70N are mounted on the substrate 30B.

[0189] In this example, unlike the second and sixth examples described above, the line capacitor 80 is connected to the ends of the DC reactors 70P and 70N on the rectifier circuit 20 side.

[0190] For example, instead of wiring pattern 30PP3, an additional wiring pattern (hereinafter, for convenience, referred to as "wiring pattern 30PP5") is provided that is disposed integrally with wiring pattern 30PP1 on one side of substrate 30B, and instead of wiring pattern 30NP3, an additional wiring pattern (hereinafter, for convenience, referred to as "wiring pattern 30NP5") is provided that is disposed integrally with wiring pattern 30NP1 on one side of substrate 30B. Specifically, for example, wiring pattern 30PP5 is disposed on one side of substrate 30B so as to protrude from wiring pattern 30PP1 in the negative direction of the Y axis, and wiring pattern 30NP5 is disposed on one side of substrate 30B so as to protrude from wiring pattern 30NP1 in the positive direction of the Y axis.

[0191] One terminal of the line capacitor 80 is connected to the wiring pattern 30PP5, and the other terminal is connected to the wiring pattern 30NP5, so that the line capacitor 80 is disposed so as to bridge the wiring patterns 30PP5 and 30NP5 in the Y-axis direction.

[0192] Moreover, in this example, unlike the second and sixth examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is arranged at the end of the DC reactor 70N on the rectifier circuit 20 side.

[0193] For example, instead of wiring pattern 30NP4, an additional wiring pattern (hereinafter, for convenience, referred to as "wiring pattern 30NP6") is provided that is disposed integrally with wiring pattern 30NP1 on one side of substrate 30B, and wiring pattern 30GP is moved to the vicinity of wiring pattern 30NP6. Specifically, for example, wiring pattern 30NP6 is disposed on one side of substrate 30B so as to protrude in the negative Y-axis direction from the same position on wiring pattern 30NP1 as wiring pattern 30NP5 in the X-axis direction, and wiring pattern 30GP is disposed so as to face wiring pattern 30NP5 in the negative Y-axis direction.

[0194] One terminal of the ground capacitor 85 is connected to the wiring pattern 30NP5, and the other terminal is connected to the wiring pattern 30GP. For example, one terminal of the ground capacitor 85 is connected to the tip of the wiring pattern 30NP5 in the negative Y-axis direction, and the other terminal is connected to the end of the wiring pattern 30GP in the positive X-axis direction, which is arranged to extend in the X-axis direction. Thus, the ground capacitor 85 is arranged to bridge between the wiring pattern 30NP5 and the wiring pattern 30GP in the Y-axis direction.

[0195] It is preferable that the land LDP1 and the portion of the wiring pattern 30PP1 corresponding to the base end of the wiring pattern 30PP5 are set as close as possible to each other. It is also preferable that the land LDN1 and the portions of the wiring pattern 30NP1 corresponding to the base ends of the wiring patterns 30NP5 and 30NP6 are set as close as possible to each other.

[0196] It is preferable that the base ends of the wiring patterns 30NP5 and 30NP6 in the wiring pattern 30NP1 are located as close to each other as possible. For example, in the wiring pattern 30NP1, the base ends of the wiring patterns 30NP5 and 30NP6 are located at the same position in the X-axis direction.

[0197] [5th ​​example of power conversion device] A fifth example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0198] In the following, components that are the same as or correspond to those in the first to fourth examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first to fourth examples described above, and explanations of the same or corresponding content as the first to fourth examples described above may be omitted.

[0199] FIG. 9 is a diagram illustrating a configuration of a fifth example of the power conversion device 1. In FIG.

[0200] 9, the power conversion device 1 according to this example differs from the first and third examples described above in that a line capacitor 80 is electrically connected to the ends of the pair of DC reactors 70P, 70N on the rectifier circuit 20 side. The power conversion device 1 according to this example also differs from the first, third, and fourth examples described above in that a ground capacitor 85 is electrically connected to the end of the DC reactor 70P on the rectifier circuit 20 side. The power conversion device 1 according to this example may be the same as the first, third, and fourth examples described above in other respects.

[0201] As in the fourth example described above, the line capacitor 80 is provided so as to electrically connect the ends of the DC reactors 70P and 70N on the rectifier circuit 20 side to each other.

[0202] The earth capacitor 85 is provided to electrically connect the end of the DC reactor 70P on the rectifier circuit 20 side to the ground GND.

[0203] In this example, similarly to the fourth example described above, when a high-frequency common mode current circulates, the ends of the DC reactors 70P, 70N on the rectifier circuit 20 side are short-circuited at high frequencies due to the action of the line capacitor 80. Therefore, the same functions and effects as those of the fourth example described above are achieved.

[0204] Furthermore, in this example, similarly to the first, third, and fourth examples described above, the action of earth capacitor 85 forms a path through which the common mode current flowing out from inverter circuit 40 to ground GND flows back to inverter circuit 40 via earth capacitor 85. This provides the same functions and effects as the first, third, and fourth examples described above.

[0205] [Fifth example of how to determine circuit constants] Continuing with reference to Fig. 9, a method for determining the circuit constants in the fifth example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0206] The following description will focus on the differences from the first to fourth examples of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first to fourth examples described above may be omitted.

[0207] For example, similar to the fourth example described above, if the positive line 30P and the negative line 30N are in a balanced state and the parasitic inductances L p ,L n , parasitic capacitance C rp ,C rn , and the parasitic capacitance EPC between both ends of each of the DC reactors 70P and 70N rp ,EPC rn Consider the case where the above equations (6) to (8) hold.

[0208] In this case, the parasitic capacitance C m , and parasitic capacitance C rp , parasitic capacitance C rn The resonant frequency fr of the circulating path of the high-frequency common mode current through the line capacitor 80 and the earth capacitor 85 is expressed by equation (9) based on equations (10) to (12), as in the fourth example described above. This is because the line capacitor 80 can be considered to be in a short-circuit state at high frequencies. Also, as in the fourth example described above, the parasitic inductance L pn , and the parasitic inductance L of the ground GND eThe resonance frequency fr may be evaluated by considering only the former of the above.

[0209] Therefore, in the same manner as in the fourth example, the capacitance C of the earth capacitor 85 is 85 can be determined.

[0210] [Example 9 of the layout of line capacitors and ground capacitors] A ninth example of the arrangement structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 2 in addition to FIG.

[0211] Hereinafter, the same symbols will be used for the same or corresponding configurations as the first, fifth, and seventh examples of the arrangement structure described above, and the explanation will focus on the parts that are different from the first, fifth, and seventh examples described above, and explanations of the parts that are the same or corresponding to the first, fifth, and seventh examples described above may be omitted.

[0212] In this example, similarly to the first example (see FIG. 2) described above, the DC reactors 70P and 70N are fixed to a housing of the power conversion device 1 that corresponds to the ground GND.

[0213] In this example, similarly to the seventh example described above, the line capacitor 80 is connected to the end of each of the DC reactors 70P and 70N on the rectifier circuit 20 side. Therefore, in this example, the arrangement structure of the line capacitor 80 is the same as that of the seventh example described above.

[0214] Furthermore, in this example, unlike the first, fifth, and seventh examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is disposed at the end of the DC reactor 70P on the rectifier circuit 20 side. Therefore, the earth capacitor 85 has one end terminal 85T1 electrically connected to the lead wire 70PL1, and the other end terminal 85T2 directly or indirectly connected to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 70PL1 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 70PC by the bolt 70PB on the left side in FIG. 2 . As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 70PB.

[0215] It is preferable that the connection points between the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 and the lead wire 70PL1 are as close as possible to the winding 70PW.

[0216] It is preferable that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70PL1 are as close as possible to each other. For example, the terminal 80T1 and the terminal 85T1 are connected to the lead wire 70PL1 so that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 70PL1 coincide with each other.

[0217] [10th example of the layout of line capacitors and ground capacitors] A tenth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 3 in addition to FIG.

[0218] Hereinafter, the same symbols will be used for the same or corresponding configurations as those in the second, fourth, sixth, and eighth examples of the arrangement structure described above, and the explanation will focus on the parts that differ from the second, fourth, sixth, and eighth examples described above, and explanations of the parts that are the same as or corresponding to those in the second, fourth, sixth, and eighth examples described above may be omitted.

[0219] In this example, similarly to the second example (see FIG. 3) described above, DC reactors 70P and 70N are mounted on the substrate 30B.

[0220] In this example, similarly to the above-described eighth example, the connection destination of the line capacitor 80 is arranged at the end of the DC reactors 70P, 70N on the side of the rectifier circuit 20. Therefore, the arrangement structure of the line capacitor 80 is the same as that of the above-described eighth example.

[0221] Furthermore, in this example, unlike the second, sixth and eighth examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is arranged at the end of the DC reactor 70P on the rectifier circuit 20 side.

[0222] For example, instead of wiring pattern 30NP4, an additional wiring pattern (hereinafter, for convenience, referred to as "wiring pattern 30PP6") is provided that is disposed integrally with wiring pattern 30PP1 on one side of substrate 30B, and wiring pattern 30GP is moved to the vicinity of wiring pattern 30PP6. Specifically, for example, wiring pattern 30PP6 is disposed on one side of substrate 30B so as to protrude in the positive Y-axis direction from the same position on wiring pattern 30PP1 as wiring pattern 30PP5 in the X-axis direction, and wiring pattern 30GP is disposed so as to face wiring pattern 30PP5 in the positive Y-axis direction.

[0223] One terminal of the ground capacitor 85 is connected to the wiring pattern 30PP6, and the other terminal is connected to the wiring pattern 30GP. For example, one terminal of the ground capacitor 85 is connected to the tip of the wiring pattern 30PP6 in the positive Y-axis direction, and the other terminal is connected to the end of the wiring pattern 30GP in the positive X-axis direction, which is arranged to extend in the X-axis direction. Thus, the ground capacitor 85 is arranged to bridge between the wiring pattern 30PP6 and the wiring pattern 30GP in the Y-axis direction.

[0224] It is preferable that the land LDN1 and the portions of the wiring pattern 30PP1 corresponding to the base ends of the wiring patterns 30PP5 and 30PP6 are set as close as possible to each other.

[0225] It is preferable that the base ends of the wiring patterns 30PP5 and 30PP6 in the wiring pattern 30PP1 are located as close to each other as possible. For example, in the wiring pattern 30PP1, the base ends of the wiring patterns 30PP5 and 30PP6 are located at the same position in the X-axis direction.

[0226] [Sixth example of a power conversion device] A sixth example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0227] In the following, components that are the same as or correspond to those in the first to fifth examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first to fifth examples described above, and explanations of the same or corresponding content as the first to fifth examples described above may be omitted.

[0228] FIG. 10 is a diagram illustrating a configuration of a sixth example of the power conversion device 1. In FIG.

[0229] The power conversion device 1 according to this example differs from the second example described above in that an earth capacitor 85 is provided to electrically connect the inverter circuit 40 side end of coil 75P of common mode choke coil 75 to ground GND. That is, in this example, compared to the second example described above, the connection destination of earth capacitor 85 on the DC line 30 side is changed from the inverter circuit 40 side end of coil 75N of negative line 30N to the inverter circuit 40 side end of coil 75P of positive line 30P. Furthermore, the power conversion device 1 according to this example may be the same as the first example described above in other respects.

[0230] In this example, similar to the second example described above, the resonant frequency of the circulating path of the high-frequency common mode current can be changed by the action of the earth capacitor 85. Therefore, the same actions and effects as those of the second example described above can be achieved.

[0231] [Sixth example of how to determine circuit constants] Continuing with reference to Fig. 10, a method for determining the circuit constants in the sixth example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0232] The following description will focus on the differences from the first to fifth examples of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first to fifth examples described above may be omitted.

[0233] The capacitance C85 of the ground capacitor 85 in the sixth example of the power conversion device 1 can be determined by the same method as in the second example, that is, the same method as in the first example, because the line capacitor 80 can be regarded as being short-circuited at high frequencies.

[0234] Specifically, "DC reactor 70P, 70N" and "parasitic capacitance C rp ,C rn " is "Coil 75P, 75N", "Parasitic capacitance C cp ,C cn ", the capacitance C of the earth capacitor 85 in the first example of the power conversion device 1 described above is 85 The explanation of the method for determining the value of the variable can be used.

[0235] [11th example of the layout of line capacitors and earth capacitors] An eleventh example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 5 in addition to FIG.

[0236] In the following, the same symbols will be used for configurations that are the same as or correspond to the third example of the arrangement structure described above, and the explanation will focus on the parts that are different from the third example described above, and explanations of the parts that are the same as or correspond to the third example described above may be omitted.

[0237] In this example, similarly to the third example (see FIG. 5) described above, the common mode choke coil 75 is fixed to a housing corresponding to the ground GND in the power conversion device 1.

[0238] In this example, the layout structure of the line capacitors 80 is the same as that of the third example described above.

[0239] In this example, unlike the third example described above, the connection destination of the DC line 30 side of the earth capacitor 85 is located at the end of the coil 75P of the common mode choke coil 75 on the inverter circuit 40 side. Therefore, one terminal 85T1 of the earth capacitor 85 is connected to the lead wire 75PL2, and the other terminal 85T2 is connected directly or indirectly to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 75PL2 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 75C by the bolt 75B on the right side in FIG. 5 . As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 75B.

[0240] It is preferable that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75PL2 are as close as possible to each other. For example, the terminal 80T1 and the terminal 85T1 are connected to the lead wire 75PL2 so that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75PL2 coincide with each other.

[0241] [12th example of the layout of line capacitors and earth capacitors] A twelfth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 6 in addition to FIG.

[0242] In the following, the same symbols will be used for configurations that are the same as or correspond to the fourth example of the arrangement structure described above, and the explanation will focus on the parts that are different from the fourth example described above, and explanations of the parts that are the same as or correspond to the fourth example described above may be omitted.

[0243] In this example, similar to the fourth example (see FIG. 6) described above, a common mode choke coil 75 is mounted on the substrate 30B.

[0244] In this example, unlike the above-described fourth example, the connection destination of the earth capacitor 85 on the DC line 30 side is arranged at the end of the coil 75P of the common mode choke coil 75 on the inverter circuit 40 side.

[0245] For example, as in the sixth example described above, in place of the wiring pattern 30NP4, an additional wiring pattern is provided that is arranged integrally with the wiring pattern 30PP2 on one side of the substrate 30B, and the wiring pattern 30GP is relocated to the vicinity of the additional wiring pattern.

[0246] One terminal of the earth capacitor 85 is connected to the additional wiring pattern, and the other terminal is connected to the wiring pattern 30GP.

[0247] As in the sixth example described above, it is preferable that the land LDP2 and the portions of the wiring pattern 30PP2 that correspond to the base ends of the wiring pattern 30PP3 and the additional wiring pattern are set as close as possible to each other.

[0248] As in the sixth example, it is preferable that the locations of the wiring pattern 30PP2 corresponding to the base ends of the wiring pattern 30PP3 and the additional wiring pattern be set as close as possible to each other.

[0249] [7th example of power conversion device] A seventh example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0250] In the following, components that are the same as or correspond to those in the first to sixth examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first to sixth examples described above, and explanations of the same or corresponding content as the first to sixth examples described above may be omitted.

[0251] FIG. 11 is a diagram illustrating a configuration of a seventh example of the power conversion device 1. In FIG.

[0252] 11, the power conversion device 1 according to this example differs from the second and sixth examples described above in that the line capacitor 80 and the ground capacitor 85 are electrically connected to the end of the common mode choke coil 75 on the rectifier circuit 20 side. In other respects, the power conversion device 1 according to this example may be the same as the first and third examples described above.

[0253] The line capacitor 80 is provided to electrically connect the ends of the coils 75P and 75N of the common mode choke coil 75 to each other.

[0254] The earth capacitor 85 is provided to electrically connect the end of the coil 75N of the common mode choke coil 75 on the rectifier circuit 20 side to the ground GND.

[0255] In this example, when a high-frequency common mode current circulates, the ends of the coils 75P, 75N of the common mode choke coil 75 on the rectifier circuit 20 side are short-circuited at high frequencies due to the action of the line capacitor 80. This suppresses imbalance between the positive line 30P and the negative line 30N when a high-frequency common mode current circulates, thereby preventing high-frequency noise current from leaking out from the input unit 10 side and the ground terminal 15 side to the outside.

[0256] Furthermore, in this example, similar to the second and sixth examples described above, the action of the earth capacitor 85 forms a path through which the common mode current flowing out from the inverter circuit 40 to the ground GND flows back to the inverter circuit 40 via the earth capacitor 85. This provides the same functions and effects as the second and sixth examples described above.

[0257] [7th example of how to determine circuit constants] Continuing with reference to Fig. 11, a method for determining the circuit constants in the seventh example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0258] The following description will focus on the differences from the first to sixth examples of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first to sixth examples described above may be omitted.

[0259] The capacitance C of the earth capacitor 85 in the seventh example of the power conversion device 1 85 can be determined in the same manner as in the fourth example of the power conversion device 1 described above.

[0260] Specifically, "DC reactor 70P, 70N" and "parasitic capacitance C rp ,C rn ”, “Parasitic capacitance EPC rp ,EPC rn " is "Coil 75P, 75N", "Parasitic capacitance C cp ,C cn ”, “Parasitic capacitance EPC cp ,EPC cn ", the capacitance C of the earth capacitor 85 in the fourth example of the power conversion device 1 described above is 85 The explanation of the method for determining the value of the variable can be used.

[0261] Furthermore, the parasitic capacitance EPC cp is the parasitic capacitance (stray capacitance) between both ends of the coil 75P, and the parasitic capacitance EPC cn is the parasitic capacitance (stray capacitance) between both ends of the coil 75N.

[0262] [13th example of the layout of line capacitors and earth capacitors] A thirteenth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 5 in addition to FIG.

[0263] Hereinafter, the same symbols will be used for the same or corresponding configurations as the third and eleventh examples of the arrangement structure described above, and the explanation will focus on the parts that are different from the third and eleventh examples described above, and explanations of the parts that are the same or corresponding to the third and eleventh examples described above may be omitted.

[0264] In this example, similarly to the third example (see FIG. 5) described above, the common mode choke coil 75 is fixed to a housing corresponding to the ground GND in the power conversion device 1.

[0265] In this example, unlike the third and eleventh examples described above, the connection destination of the line capacitor 80 is disposed at the end of each of the coils 75P and 75N of the common mode choke coil 75 on the rectifier circuit 20 side. Therefore, one terminal 80T1 of the line capacitor 80 is electrically connected to the lead wire 75PL1, and the other terminal 80T2 is connected to the lead wire 75NL1. For example, the terminals 80T1 and 80T2 are connected to the lead wires 75PL1 and 75NL1, respectively, using soldering, a sleeve, or the like.

[0266] Furthermore, in this example, unlike the third and eleventh examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is located at the end of the coil 75N of the common mode choke coil 75 on the rectifier circuit 20 side. Therefore, one terminal 85T1 of the earth capacitor 85 is electrically connected to the lead wire 75NL1, and the other terminal 85T2 is directly or indirectly connected to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 75NL1 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 75C by the bolt 75B on the left side in FIG. 5 . As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 75B.

[0267] It is preferable that the connection point between terminal 80T1 of line capacitor 80 and lead wire 75PL1 be as close as possible to coil 75P. It is also preferable that the connection points between terminal 80T2 of line capacitor 80 and lead wire 75NL1 of terminal 85T1 of earth capacitor 85 are as close as possible to coil 75N.

[0268] It is preferable that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75NL1 are as close as possible to each other. For example, the terminal 80T2 and the terminal 85T1 are connected to the lead wire 75NL1 so that the connection points of the terminal 80T2 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75NL1 coincide with each other.

[0269] [14th example of the layout of line capacitors and earth capacitors] A fourteenth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 6 in addition to FIG.

[0270] Hereinafter, the same symbols will be used for configurations that are the same as or correspond to the second, fourth, sixth, eighth, tenth, and twelfth examples of the above-mentioned arrangement structure, and the explanation will focus on the parts that are different from the second, fourth, sixth, eighth, tenth, and twelfth examples described above, and explanations of the parts that are the same as or correspond to the second, fourth, sixth, eighth, tenth, and twelfth examples described above may be omitted.

[0271] In this example, similar to the fourth example (see FIG. 6) described above, a common mode choke coil 75 is mounted on the substrate 30B.

[0272] In this example, unlike the fourth and twelfth examples described above, the connection destination of the line capacitor 80 is arranged at the end of the coils 75P and 75N of the common mode choke coil 75 on the rectifier circuit 20 side.

[0273] For example, as in the above-mentioned eighth example, instead of wiring pattern 30PP3, an additional wiring pattern (wiring pattern 30PP5) is provided that is arranged integrally with wiring pattern 30PP1 on one side of substrate 30B, and instead of wiring pattern 30NP3, an additional wiring pattern (wiring pattern 30NP5) is provided that is arranged integrally with wiring pattern 30NP1 on one side of substrate 30B.

[0274] One terminal of the line capacitor 80 is connected to the wiring pattern 30PP5, and the other terminal is connected to the wiring pattern 30NP5.

[0275] Furthermore, in this example, unlike the fourth and twelfth examples described above, the connection destination of the earth capacitor 85 on the DC line 30 side is arranged at the end of the coil 75N of the common mode choke coil 75 on the rectifier circuit 20 side.

[0276] For example, as in the eighth example described above, in place of wiring pattern 30NP4, an additional wiring pattern (wiring pattern 30NP6) is provided that is arranged integrally with wiring pattern 30NP1 on one side of substrate 30B, and wiring pattern 30GP is relocated to the vicinity of wiring pattern 30NP6.

[0277] One terminal of the earth capacitor 85 is connected to the wiring pattern 30NP5, and the other terminal is connected to the wiring pattern 30GP.

[0278] As in the above-described eighth example, it is preferable that the land LDP1 and the portion of the wiring pattern 30PP1 corresponding to the base end of the wiring pattern 30PP5 are set as close as possible to each other. Also, it is preferable that the land LDN1 and the portions of the wiring pattern 30NP1 corresponding to the base ends of the wiring patterns 30NP5 and 30NP6 are set as close as possible to each other.

[0279] As in the above-described eighth example, it is preferable that the portions of the wiring pattern 30NP1 corresponding to the base ends of the wiring patterns 30NP5 and 30NP6 are set as close as possible to each other.

[0280] [Example 8 of a power conversion device] An eighth example of the power conversion device 1 according to this embodiment will be described with reference to FIG.

[0281] In the following, components that are the same as or correspond to those in the first to seventh examples of the power conversion device 1 described above will be given the same symbols, and the explanation will focus on the parts that are different from the first to seventh examples described above, and explanations of the same or corresponding content as the first to seventh examples described above may be omitted.

[0282] FIG. 12 is a diagram illustrating the configuration of an eighth example of the power conversion device 1. In FIG.

[0283] 12, the power conversion device 1 according to this embodiment differs from the second and sixth embodiments described above in that a line capacitor 80 is electrically connected to the rectifier circuit 20 side end of coils 75P and 75N of the common mode choke coil 75. The power conversion device 1 according to this embodiment also differs from the second, sixth, and seventh embodiments described above in that a ground capacitor 85 is electrically connected to the rectifier circuit 20 side end of coil 75P of the common mode choke coil 75. The power conversion device 1 according to this embodiment may be the same as the second, sixth, and seventh embodiments described above in other respects.

[0284] The line capacitor 80 is provided so as to electrically connect the ends of the coils 75P and 75N of the common mode choke coil 75 on the rectifier circuit 20 side to each other, as in the seventh example described above.

[0285] The earth capacitor 85 is provided to electrically connect the end of the coil 75P of the common mode choke coil 75 on the rectifier circuit 20 side to the ground GND.

[0286] In this example, similarly to the seventh example described above, when a high-frequency common mode current circulates, the ends of the coils 75P, 75N of the common mode choke coil 75 on the rectifier circuit 20 side are short-circuited at high frequencies due to the action of the line capacitor 80. Therefore, the same functions and effects as those of the seventh example described above are achieved.

[0287] Furthermore, in this example, similarly to the second, sixth, and seventh examples described above, the action of the earth capacitor 85 forms a path through which the common mode current flowing out from the inverter circuit 40 to the ground GND flows back to the inverter circuit 40 via the earth capacitor 85. This provides the same functions and effects as the second, sixth, and seventh examples described above.

[0288] [Example 8 of how to determine circuit constants] Continuing with reference to Fig. 12, a method for determining the circuit constants in the eighth example of the power conversion device 1 will be described. Specifically, the capacitance C 85 The method for determining this will be explained below.

[0289] The following description will focus on the differences from the first to seventh examples of the method for determining circuit constants described above, and descriptions of the same or corresponding parts as the first to seventh examples described above may be omitted.

[0290] The capacitance C of the earth capacitor 85 in the eighth example of the power conversion device 1 85 can be determined in the same manner as in the case of the above-described seventh example of the power conversion device 1. This is because the line capacitor 80 can be regarded as being in a short-circuit state at high frequencies.

[0291] Specifically, as in the seventh example described above, “DC reactors 70P, 70N” and “parasitic capacitance C rp ,C rn ”, “Parasitic capacitance EPC rp ,EPC rn " is "Coil 75P, 75N", "Parasitic capacitance C cp ,C cn ”, “Parasitic capacitance EPC cp ,EPC cn ", the capacitance C of the earth capacitor 85 in the fourth example of the power conversion device 1 described above is 85 The explanation of the method for determining the value of the variable can be used.

[0292] [15th example of the layout of line capacitors and earth capacitors] A fifteenth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 5 in addition to FIG.

[0293] Hereinafter, the same symbols will be used for the same or corresponding configurations as those in the third, eleventh, and thirteenth examples of the arrangement structure described above, and the explanation will focus on the parts that differ from the third, eleventh, and thirteenth examples described above, and explanations of the parts that are the same or corresponding to those in the third, eleventh, and thirteenth examples described above may be omitted.

[0294] In this example, similarly to the third example (see FIG. 5) described above, the common mode choke coil 75 is fixed to a housing corresponding to the ground GND in the power conversion device 1.

[0295] In this example, similarly to the above-described thirteenth example, the connection destination of the line capacitor 80 is arranged at the end of each of the DC reactors 70P, 70N on the side of the rectifier circuit 20. Therefore, in this example, the arrangement structure of the line capacitor 80 is the same as that of the above-described thirteenth example.

[0296] Furthermore, in this example, unlike the third, eleventh, and thirteenth examples described above, the connection destination of the ground capacitor 85 on the DC line 30 side is located at the end of the coil 75P of the common mode choke coil 75 on the rectifier circuit 20 side. Therefore, the ground capacitor 85 has one end terminal 85T1 electrically connected to the lead wire 75PL1, and the other end terminal 85T2 directly or indirectly connected to the housing of the power converter 1. For example, the terminal 85T1 is connected to the lead wire 75PL1 using soldering, a sleeve, or the like. For example, the terminal 85T2 is fastened together with the magnetic core 75C by the bolt 75B on the left side in FIG. 5 . As a result, the terminal 85T2 is electrically connected to the housing of the power converter 1 through the bolt 75B.

[0297] It is preferable that the connection points between the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 and the lead wire 70PL1 are as close as possible to the coil 75P.

[0298] It is preferable that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75PL1 are as close as possible to each other. For example, the terminal 80T1 and the terminal 85T1 are connected to the lead wire 75PL1 so that the connection points of the terminal 80T1 of the line capacitor 80 and the terminal 85T1 of the earth capacitor 85 with the lead wire 75PL1 coincide with each other.

[0299] [16th example of the layout of line capacitors and ground capacitors] A sixteenth example of the layout structure of the line capacitors 80 and the ground capacitors 85 will be described with reference to FIG. 6 in addition to FIG.

[0300] Hereinafter, the same symbols will be used for configurations that are the same as or correspond to the second, fourth, sixth, eighth, tenth, twelfth, and fourteenth examples of the arrangement structure described above, and the explanation will focus on the parts that are different from the second, fourth, sixth, eighth, tenth, twelfth, and fourteenth examples described above, and explanations of the parts that are the same as or correspond to the second, fourth, sixth, eighth, tenth, twelfth, and fourteenth examples described above may be omitted.

[0301] In this example, similarly to the fourth example (see FIG. 6) described above, DC reactors 70P and 70N are mounted on the substrate 30B.

[0302] In this example, similarly to the above-described fourteenth example, the connection destination of the line capacitor 80 is arranged at the end of the coils 75P, 75N of the common mode choke coil 75 on the rectifier circuit 20 side. Therefore, the arrangement structure of the line capacitor 80 is the same as that of the above-described fourteenth example.

[0303] Furthermore, in this example, unlike the above-mentioned fourth, twelfth, and fourteenth examples, the connection destination of the DC line 30 side of the earth capacitor 85 is arranged at the end of the coil 75P of the common mode choke coil 75 on the rectifier circuit 20 side.

[0304] For example, as in the above-mentioned tenth example, in place of wiring pattern 30NP4, an additional wiring pattern (wiring pattern 30PP6) is provided that is arranged integrally with wiring pattern 30PP1 on one side of substrate 30B, and wiring pattern 30GP is relocated to the vicinity of wiring pattern 30PP6.

[0305] One terminal of the earth capacitor 85 is connected to the wiring pattern 30PP6, and the other terminal is connected to the wiring pattern 30GP.

[0306] As in the above-described tenth example, it is preferable that the portions of the wiring pattern 30PP1 corresponding to the base ends of the wiring patterns 30PP5 and 30PP6 and the land LDN1 are set as close as possible to each other.

[0307] As in the above-described tenth example, it is preferable that the base ends of the wiring patterns 30PP5 and 30PP6 in the wiring pattern 30PP1 are located as close to each other as possible. For example, in the wiring pattern 30PP1, the base ends of the wiring patterns 30PP5 and 30PP6 are located at the same position in the X-axis direction.

[0308] [Other examples of power conversion devices] Next, another example of the power conversion device 1 according to this embodiment will be described.

[0309] The power conversion device 1 of the above-described embodiment may be modified or changed as appropriate. Hereinafter, examples of modifications or changes made to the power conversion device 1 of the above-described embodiment will be referred to as "modifications" for convenience.

[0310] For example, in the first and third to fifth examples of the power conversion device 1 described above, a line capacitor 80 may be provided both between the inverter circuit 40 side ends of the DC reactors 70P, 70N and between the rectifier circuit 20 side ends of the DC reactors 70P, 70N. For example, the power conversion device 1 of the first and third examples described above is additionally provided with a line capacitor 80 arranged to electrically connect the rectifier circuit 20 side ends of the DC reactors 70P, 70N.

[0311] Similarly, in the second, sixth to eighth examples of the power conversion device 1 described above, a line capacitor 80 may be provided both between the inverter circuit 40 side ends of the coils 75P, 75N of the common mode choke coil 75 and between the rectifier circuit 20 side ends of the coils 75P, 75N. For example, the power conversion devices 1 of the seventh and eighth examples described above have line capacitors 80 added thereto so as to electrically connect the inverter circuit 40 side ends of the coils 75P, 75N of the common mode choke coil 75.

[0312] Furthermore, in the first, third to fifth examples and their modifications of the power conversion device 1 described above, the earth capacitor 85 may be provided in two or more of the four paths connecting the end of the DC reactor 70P on the inverter circuit 40 side, the end of the DC reactor 70N on the inverter circuit 40 side, the end of the DC reactor 70P on the rectifier circuit 20 side, and the end of the DC reactor 70N on the rectifier circuit 20 side to the ground GND. For example, in the first example and its modifications described above, the earth capacitor 85 is added to at least one of the three paths connecting the end of the DC reactor 70P on the inverter circuit 40 side, the end of the DC reactor 70P on the rectifier circuit 20 side, and the end of the DC reactor 70N on the rectifier circuit 20 side to the ground GND.

[0313] Furthermore, in the second, sixth to eighth examples of the power conversion device 1 described above and their modified examples, the earth capacitor 85 may be provided in two or more of the four paths connecting the end of the coil 75P on the inverter circuit 40 side, the end of the coil 75N on the inverter circuit 40 side, the end of the coil 75P on the rectifier circuit 20 side, and the end of the coil 75N on the rectifier circuit 20 side to the ground GND. For example, in the second example and its modified examples described above, the earth capacitor 85 is added to at least one of the three paths connecting the end of the coil 75P on the inverter circuit 40 side, the end of the coil 75P on the rectifier circuit 20 side, and the end of the coil 75N on the rectifier circuit 20 side to the ground GND.

[0314] In the above-described embodiment, other types of switching circuits including a semiconductor switch SW may be provided instead of the inverter circuit 40. For example, the power conversion device 1 may include a half-bridge inverter circuit instead of the inverter circuit 40.

[0315] In the above-described embodiment and its modifications, DC may be supplied from an external power supply to the power conversion device 1. In this case, the rectifier circuit 20 is omitted, and the DC from the external power supply is directly input to the DC line 30.

[0316] In the above-described embodiment and its modifications, a single-phase AC may be supplied from an external power supply to the power conversion device 1. In this case, the rectifier circuit 20 is replaced with a rectifier circuit that converts the single-phase AC into DC.

[0317] In the above-described embodiment and its modifications, the power conversion device 1 may drive a single-phase AC load device. In this case, the inverter circuit 40 is replaced with an inverter circuit that converts DC into single-phase AC of a predetermined voltage and frequency and outputs the converted AC.

[0318] In the above-described embodiment and its modifications, the power conversion device 1 may drive a DC load device. In this case, the inverter circuit 40 is replaced with a DC / DC converter that converts DC into a predetermined DC voltage and outputs the converted DC voltage as a switching circuit.

[0319] [Effect] Next, the operation of the power conversion device and the circuit constant determination method according to this embodiment will be described.

[0320] In a first aspect of this embodiment, the power conversion device includes a switching circuit, a DC line, a pair of DC reactors, a first capacitor, and a second capacitor. The power conversion device is, for example, the power conversion device 1 shown in FIG. 1. The switching circuit is, for example, the inverter circuit 40 shown in FIG. 1. The DC line is, for example, the DC line 30 shown in FIG. 1. The pair of DC reactors are, for example, the DC reactors 70P and 70N shown in FIG. 1. The first capacitor is, for example, the line-to-line capacitor 80 shown in FIG. 1. The second capacitor is, for example, the ground capacitor 85 shown in FIG. 1. Specifically, the switching circuit includes a semiconductor switch. The semiconductor switch is, for example, the semiconductor switch SW shown in FIG. 1. The DC line includes a positive line and a negative line, and inputs DC to the switching circuit. The positive line and the negative line are, for example, the positive line 30P and the negative line 30N, respectively. The pair of DC reactors are provided on the positive line and the negative line. The first capacitor is provided to connect the ends of the DC reactor on the positive line and the DC reactor on the negative line on the switching circuit side or the ends on the opposite side from the switching circuit. The DC reactor on the positive line and the DC reactor on the negative line are, for example, the DC reactor 70P and the DC reactor 70N described above, respectively. The second capacitor is provided to connect the ends of the DC reactor on the positive line or the negative line on the switching circuit side or the opposite side from the switching circuit to a conductive part corresponding to a reference potential. The conductive part corresponding to the reference potential is, for example, the above-mentioned ground GND.

[0321] As a result, the power conversion device can suppress the imbalance between the positive line and the negative line at high frequencies through the action of the first capacitor, thereby suppressing the leakage of common-mode noise to the outside. Furthermore, the power conversion device can adjust the resonant frequency of the common-mode circulation path including the section of the DC line between the pair of DC reactors and the switching circuit through the action of the second capacitor, thereby moving it out of the high-frequency band where radiated noise is a problem. Therefore, the power conversion device can suppress the radiated noise caused by the switching operation of the switching circuit.

[0322] In a second aspect of this embodiment, based on the first aspect described above, a capacitance component between the switching circuit and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor on the positive line and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor on the negative line and the conductive part corresponding to the reference potential, and the second capacitor may be set to a predetermined value or less such that a resonance frequency of a path circulating between the DC line and the conductive part of the reference potential is set to 1 MHz or more. The capacitance component between the switching circuit and the conductive part corresponding to the reference potential may be, for example, a parasitic capacitance C m The capacitance component between the DC reactor of the positive line and the conductive part corresponding to the reference potential is, for example, the above-mentioned parasitic capacitance C rp The capacitance component between the DC reactor of the negative line and the conductive part corresponding to the reference potential is, for example, the above-mentioned parasitic capacitance C rn The predetermined value is, for example, the lower limit value fmin described above.

[0323] This allows the power conversion device to adjust the resonant frequency of the common mode circulating path including the section of the DC line between the pair of DC reactors and the switching circuit, and to remove it from the band above a certain value where radiated noise becomes a problem.

[0324] Furthermore, in a third aspect of this embodiment, assuming the first or second aspect described above, the capacitance of the second capacitor may be larger than the capacitance of a capacitance component between the DC reactor on the positive line and the conductive part corresponding to the reference potential, and the capacitance component between the DC reactor on the negative line and the conductive part corresponding to the reference potential.

[0325] This allows the power conversion device to increase the contribution of the second capacitor to the resonant frequency of the common-mode circulating path including the section of the DC line between the pair of DC reactors and the switching circuit, thereby adjusting the resonant frequency of the common-mode circulating path including the section of the DC line between the pair of DC reactors and the switching circuit to move it out of the high-frequency band where radiation noise becomes a problem.

[0326] In a fourth aspect of this embodiment, the power conversion device includes a switching circuit, a DC line, a common-mode choke coil, a third capacitor, and a fourth capacitor. The power conversion device is, for example, the power conversion device 1 shown in FIG. 4. The switching circuit is, for example, the inverter circuit 40 shown in FIG. 4. The DC line is, for example, the DC line 30 shown in FIG. 4. The common-mode choke coil is, for example, the common-mode choke coil 75 shown in FIG. 4. The third capacitor is, for example, the line capacitor 80 shown in FIG. 4. The fourth capacitor is, for example, the ground capacitor 85 shown in FIG. 4. Specifically, the switching circuit includes a semiconductor switch. The semiconductor switch is, for example, the semiconductor switch SW shown in FIG. 4. The DC line includes a positive line and a negative line, and inputs DC to the switching circuit. The positive line and the negative line are, for example, the positive line 30P and the negative line 30N, respectively. The common mode choke coil is provided on the DC line. The third capacitor is provided to connect the ends of the positive and negative line coils of the common mode choke coil on the switching circuit side or the ends opposite the switching circuit. The positive and negative line coils of the common mode choke coil are, for example, the above-mentioned coils 75P and 75N. The fourth capacitor is provided to connect the ends of the positive or negative line coil of the common mode choke coil on the switching circuit side or the end opposite the switching circuit to a conductive part corresponding to a reference potential. The conductive part corresponding to the reference potential is, for example, the ground GND in FIG. 4.

[0327] As a result, the power conversion device can suppress the imbalance between the positive line and the negative line at high frequencies through the action of the third capacitor, thereby suppressing the leakage of common-mode noise to the outside. Furthermore, the power conversion device can adjust the resonant frequency of the common-mode circulation path, including the section of the DC line between the common-mode choke coil and the switching circuit, through the action of the fourth capacitor, thereby removing it from the high-frequency band where radiated noise is a problem. Therefore, the power conversion device can suppress radiated noise caused by the switching operation of the switching circuit.

[0328] In a fifth aspect of this embodiment, based on the fourth aspect described above, the capacitance component between the switching circuit and the conductive part corresponding to the reference potential, the capacitance component between the positive line coil and the conductive part corresponding to the reference potential in the common mode choke coil, the capacitance component between the negative line coil and the conductive part corresponding to the reference potential in the common mode choke coil, and the fourth capacitor may be equal to or less than a predetermined value that sets the resonance frequency of a path circulating between the DC line and the conductive part of the reference potential to 1 MHz or more. The capacitance component between the switching circuit and the conductive part corresponding to the reference potential may be, for example, the parasitic capacitance C m The capacitance component between the positive line coil and the conductive part corresponding to the reference potential in the common mode choke coil is, for example, the above-mentioned parasitic capacitance C cp The capacitance component between the negative line coil and the conductive part corresponding to the reference potential in the common mode choke coil is, for example, the above-mentioned parasitic capacitance C cn is.

[0329] This allows the power conversion device to adjust the resonant frequency of the common mode circulation path including the section of the DC line between the common mode choke coil and the switching circuit, and to remove it from the band above a certain value where radiated noise becomes a problem.

[0330] Furthermore, in a sixth aspect of this embodiment, assuming the fourth or fifth aspect described above, the capacitance of the fourth capacitor may be larger than the capacitance component between the positive line coil in the common mode choke coil and the conductive part corresponding to the reference potential, and the capacitance component between the negative line coil in the common mode choke coil and the conductive part corresponding to the reference potential.

[0331] This allows the power conversion device to increase the contribution of the second capacitor to the resonant frequency of the common-mode circulating path including the section of the DC line between the common-mode choke coil and the switching circuit, thereby adjusting the resonant frequency of the common-mode circulating path including the section of the DC line between the common-mode choke coil and the switching circuit to move it out of the high-frequency band where radiation noise is a problem.

[0332] In addition, in a seventh aspect of this embodiment, on the premise of the second or fifth aspect described above, the predetermined value may be 30 MHz.

[0333] This allows the power conversion device to adjust the resonance frequency of the common mode circulating path including the section of the DC line between the pair of DC reactors and the switching circuit, and to move it out of the band of 30 MHz or higher.

[0334] In addition, in an eighth aspect of the present embodiment, a circuit constant determination method is disclosed for a circuit including: a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line and inputting DC to the switching circuit; a pair of DC reactors provided on the positive line and the negative line; a first capacitor provided to connect ends of the DC reactor on the positive line and the DC reactor on the negative line on the switching circuit side or on the opposite side from the switching circuit; and a second capacitor provided to connect ends of the DC reactor on the positive line or the negative line on the switching circuit side or on the opposite side from the switching circuit and a conductive part corresponding to a reference potential. A target circuit for the circuit constant determination method of this aspect is, for example, the circuit of the power conversion device 1 shown in FIG. 1 described above. Specifically, in the circuit constant determination method of this aspect, the capacitance of the second capacitor is determined so that the resonant frequency of a path circulating between the DC line and the conductive part of the reference potential via the capacitance component between the switching circuit and the conductive part corresponding to the reference potential, the capacitance component between the DC reactor on the positive line and the conductive part corresponding to the reference potential, the capacitance component between the DC reactor on the negative line and the conductive part corresponding to the reference potential, and the second capacitor is equal to or less than a predetermined value set to 1 MHz or more.

[0335] This makes it possible to adjust the resonance frequency of the common mode circulation path including the section of the DC line between the pair of DC reactors and the switching circuit, and to remove it from a band above a predetermined value where radiation noise becomes a problem.

[0336] In addition, a ninth aspect of the present embodiment provides a method for determining circuit constants for a circuit including a switching circuit including a semiconductor switch, a DC line including a positive line and a negative line and inputting DC to the switching circuit, a common mode choke coil provided on the DC line, a third capacitor provided to connect ends of the coils of the positive line and the negative line of the common mode choke coil on the switching circuit side or on the opposite side from the switching circuit, and a fourth capacitor provided to connect ends of the coils of the positive line or the negative line of the common mode choke coil on the switching circuit side or on the opposite side from the switching circuit and a conductive part corresponding to a reference potential.The target circuit of the circuit constant determination method of this aspect is, for example, the circuit of the power conversion device 1 shown in Figure 4 above. Specifically, in this circuit constant determination method, the capacitance of the fourth capacitor is determined so that the resonant frequency of a path circulating between the DC line and the conductive part of the reference potential via the capacitance component between the switching circuit and the conductive part corresponding to the reference potential, the capacitance component between the positive line coil in the common mode choke coil and the conductive part corresponding to the reference potential, the capacitance component between the negative line coil in the common mode choke coil and the conductive part corresponding to the reference potential, and the fourth capacitor is equal to or less than a predetermined value set to 1 MHz or more.

[0337] This makes it possible to adjust the resonance frequency of the common mode circulation path including the section of the DC line between the common mode choke coil and the switching circuit, and to remove it from the band above a predetermined value where radiation noise becomes a problem.

[0338] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0339] 1 Power conversion device 10 Input section 10R input terminal 10S input terminal 10T input terminal 15 Ground terminal 20 Rectifier circuit 30 DC line 30N negative line 30P positive line 40 Inverter circuit 50 Output section 50U output terminal 50V output terminal 50W output terminal 55 Ground terminal 60 Smoothing capacitor 65 Line capacitor 70N DC reactor 70P DC reactor 75 Common mode choke coil 75C magnetic core 75N coil 75P coil 80 Line capacitor 85 Earth capacitor C cn parasitic capacitance C cp parasitic capacitance C m parasitic capacitance C mn parasitic capacitance C mo parasitic capacitance C mp parasitic capacitance C rn parasitic capacitance C rp parasitic capacitance EPC cn parasitic capacitance EPC cp parasitic capacitance EPC rn parasitic capacitance EPC rp parasitic capacitance FD freewheeling diode GND Ground LDN1 Land LDN2 Land LDP1 Land LDP2 Land L p Parasitic inductance RD rectifier diode SW Semiconductor switch

Claims

1. a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a pair of DC reactors provided on the positive line and the negative line; a first capacitor provided to connect ends of the DC reactor on the positive line and the DC reactor on the negative line on the side of the switching circuit or between ends of the DC reactor on the opposite side to the switching circuit; a second capacitor provided to connect an end of the DC reactor on the positive line or the negative line on the side of the switching circuit or on the side opposite to the switching circuit and a conductive portion corresponding to a reference potential; Power conversion device.

2. a resonant frequency of a path circulating between the DC line and the conductive part of the reference potential via a capacitance component between the switching circuit and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the positive line and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the negative line and the conductive part corresponding to the reference potential, and the second capacitor is equal to or lower than a predetermined value set to 1 MHz or higher; The power conversion device according to claim 1 .

3. a capacitance of the second capacitor is larger than a capacitance component between the DC reactor on the positive line and the conductive part corresponding to the reference potential and a capacitance component between the DC reactor on the negative line and the conductive part corresponding to the reference potential; The power conversion device according to claim 1 or 2.

4. a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a common mode choke coil provided on the DC line; a third capacitor provided to connect ends of the positive line and the negative line of the common mode choke coil on the switching circuit side or between ends of the positive line and the negative line of the common mode choke coil on the opposite side to the switching circuit; a fourth capacitor provided to connect an end of the common mode choke coil on the switching circuit side or on the opposite side to the switching circuit of the coil of the positive line or the negative line and a conductive part corresponding to a reference potential; Power conversion device.

5. a resonant frequency of a path circulating between the DC line and the conductive portion of the reference potential via a capacitance component between the switching circuit and the conductive portion corresponding to the reference potential, a capacitance component between the positive line coil and the conductive portion corresponding to the reference potential in the common mode choke coil, a capacitance component between the negative line coil and the conductive portion corresponding to the reference potential in the common mode choke coil, and the fourth capacitor is equal to or less than a predetermined value set to 1 MHz or more; The power conversion device according to claim 4.

6. the capacitance of the fourth capacitor is larger than the capacitance of a capacitance component between the positive line coil and the conductive part corresponding to the reference potential in the common mode choke coil, and the capacitance component between the negative line coil and the conductive part corresponding to the reference potential in the common mode choke coil; The power conversion device according to claim 4 or 5.

7. a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a pair of DC reactors provided on the positive line and the negative line; a first capacitor provided to connect ends of the DC reactor on the positive line and the DC reactor on the negative line on the side of the switching circuit or between ends of the DC reactor on the opposite side to the switching circuit; a second capacitor provided to connect an end of the DC reactor on the positive line or the negative line on the side of the switching circuit or on the side opposite to the switching circuit and a conductive part corresponding to a reference potential, determining a capacitance of the second capacitor so that a resonance frequency of a path circulating between the DC line and the conductive part of the reference potential via a capacitance component between the switching circuit and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the positive line and the conductive part corresponding to the reference potential, a capacitance component between the DC reactor of the negative line and the conductive part corresponding to the reference potential, and the second capacitor is equal to or less than a predetermined value set to 1 MHz or more, How to determine circuit constants.

8. a switching circuit including a semiconductor switch; a DC line including a positive line and a negative line, for inputting DC to the switching circuit; a common mode choke coil provided on the DC line; a third capacitor provided to connect ends of the positive line and the negative line of the common mode choke coil on the switching circuit side or between ends of the positive line and the negative line of the common mode choke coil on the opposite side to the switching circuit; a fourth capacitor provided to connect an end of the positive line or negative line coil on the switching circuit side or on the opposite side to the switching circuit and a conductive part corresponding to a reference potential in the common mode choke coil, a capacitance of the fourth capacitor is determined so that a resonance frequency of a path circulating between the DC line and the conductive portion of the reference potential via a capacitance component between the switching circuit and the conductive portion corresponding to the reference potential, a capacitance component between the positive line coil in the common mode choke coil and the conductive portion corresponding to the reference potential, a capacitance component between the negative line coil in the common mode choke coil and the conductive portion corresponding to the reference potential, and the fourth capacitor is equal to or less than a predetermined value set to 1 MHz or more, How to determine circuit constants.

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