Power Conversion Equipment

Abstract

To provide power convert equipment having reduced common mode noise while reducing the space allocated for noise suppression components.SOLUTION: A convert section (10) adjusts the voltage of DC power supplied from a DC power source (2) and outputs it. An inverter section (20) converts the DC power output from the convert section (10) into AC power. A board-mounted common mode choke coil (Lc) is connected to the wiring to which a switching element (Q11) in the convert section (10) is connected and the wiring to which switching elements (Q21-Q24) in the inverter section (20) are connected. The common mode choke coil (Lc) has broadband impedance characteristics corresponding to noise in multiple target bandwidths generated by the switching elements (Q11, Q21-Q24).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device including an inverter. [Background technology]

[0002] In recent years, photovoltaic power generation systems and power storage systems have become widespread. These distributed power supply systems use power conditioners that include converters and inverters. When the switching elements that make up the converter or inverter are driven by the PWM (Pulse Width Modulation) method, the switching elements generate two types of noise: noise according to the operating frequency and noise caused by abrupt current changes at the rise or fall of the pulse (see Figure 2).

[0003] High-frequency noise generated from a switching element passes through stray capacitance (also called parasitic capacitance) between the substrate on which the switching element is mounted and the housing earth, and returns to the current line of the power conditioner via the housing earth (see, for example, Patent Document 1). Conventionally, in order to block the common mode current caused by this high-frequency noise from the DC power supply and the system power supply, a choke coil is wound around each of the harnesses connected to the input and output of the substrate (see FIG. 1). In this case, two types of choke coils, a low-frequency choke coil and a high-frequency choke coil, are wound around the harness to deal with two types of noise: noise according to the operating frequency of the switching element (for example, about 20 kHz to 40 kHz) and noise caused by a steep current change at the rise or fall of a pulse (for example, about 10 MHz to 30 MHz). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-161024 A [Patent Document 2] JP 2020-9900 A Summary of the Invention [Problem to be solved by the invention]

[0005] The above measures require a large space in the power conditioner's housing to install a choke coil for common mode noise removal. In addition, a large high-frequency noise loop is formed in the board, resulting in a high noise level. The radiated noise emitted into the air from the wiring and housing is also high.

[0006] The present disclosure has been made in consideration of these circumstances, and has an object to provide a power conversion device in which common-mode noise is reduced while reducing the space required for noise suppression components. [Means for solving the problem]

[0007] In order to solve the above problems, a power conversion device according to an embodiment of the present disclosure includes a converter section capable of adjusting the voltage of DC power supplied from a DC power source and outputting the adjusted voltage, an inverter section that converts the DC power output from the converter section into AC power, wiring to which switching elements included in the converter section are connected, and a substrate-mounted common mode choke coil connected to the wiring to which the switching elements included in the inverter section are connected. The common mode choke coil has wideband impedance characteristics corresponding to noise in multiple target bands generated by the switching elements. Effect of the Invention

[0008] According to the present disclosure, in a power conversion device, it is possible to reduce common-mode noise while reducing the space allocated to noise suppression components. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram for explaining a configuration example of a power conversion device according to a comparative example. [Diagram 2]4 is a diagram showing a basic waveform of a PWM signal supplied to a gate terminal of a switching element. FIG. [Diagram 3] FIG. 2 is a diagram for explaining a first configuration example of the power conversion device according to the first embodiment. [Figure 4] 10 is a diagram for explaining a first application example of the first configuration example of the power conversion device according to the first embodiment. FIG. [Diagram 5] 10 is a diagram for explaining a second application example of the first configuration example of the power conversion device according to the first embodiment. FIG. [Figure 6] FIG. 4 is a diagram for explaining a second configuration example of the power conversion device according to the first embodiment. [Figure 7] FIG. 11 is a diagram for explaining a configuration example of a power conversion device according to a second embodiment. [Figure 8] FIG. 11 is a diagram for explaining a configuration example of a power conversion device according to a third embodiment. [Figure 9] 1 is a diagram illustrating a configuration example of a wideband common mode choke coil according to an embodiment; [Figure 10] 4 is a diagram showing frequency-impedance characteristics of a wideband common mode choke coil according to an embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1 is a diagram for explaining a configuration example of a power conversion device 1 according to a comparative example. The power conversion device 1 is a power conditioner that converts DC power generated by a solar cell 2 into AC power. The power conversion device 1 basically includes a converter unit 10, an inverter unit 20, a filter unit 30, and a system wiring connection unit 40.

[0011] The solar cell 2 is a power generation device that utilizes the photovoltaic effect to directly convert light energy into DC power. As the solar cell 2, a silicon solar cell, a solar cell made of a material such as a compound semiconductor, a dye-sensitized solar cell, an organic thin-film solar cell, etc. are used. The solar cell 2 is connected to the converter unit 10 of the power conversion device 1, and outputs the generated power to the power conversion device 1.

[0012] The converter unit 10 is a converter that is connected between the solar cell 2 and the DC bus Bd and is capable of adjusting the voltage of the DC power output from the solar cell 2. The converter unit 10 shown in Fig. 1 is configured as a boost chopper.

[0013] The converter unit 10 includes a DC reactor Ld, a diode D11, and a switching element Q11. The DC reactor Ld is inserted into the positive wiring connected to the positive terminal of the solar cell 2. The diode D11 and the switching element Q11 are connected in series between the positive wiring and the negative wiring of the DC bus Bd. The diode D11 is connected in such a direction that the switching element Q11 side is the anode and the positive wiring side of the DC bus Bd is the cathode, and the anode terminal of the diode D11 is connected to the collector terminal (or drain terminal) of the switching element Q11. The positive wiring from the solar cell 2, in which the DC reactor Ld is inserted, is connected to the connection point between the diode D11 and the switching element Q11.

[0014] A diode is connected or formed in anti-parallel to the switching element Q11. When an IGBT (Insulated Gate Bipolar Transistor) is used for the switching element Q11 as shown in Fig. 1, an external diode is connected in anti-parallel between the collector and emitter of the IGBT. When an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is used for the switching element Q11, a parasitic diode is formed from the source to the drain.

[0015] A drive control unit (not shown) of the power conversion device 1 controls the converter unit 10 by MPPT (Maximum Power Point Tracking) so that the output power of the solar cell 2 is maximized. Specifically, the drive control unit measures the input voltage and input current of the converter unit 10, which are the output voltage and output current of the solar cell 2, to estimate the power generated by the solar cell 2. The drive control unit generates a command value for making the power generated by the solar cell 2 a maximum power point (optimum operating point) based on the measured output voltage of the solar cell 2 and the estimated power generation. For example, the drive control unit changes the operating point voltage by a predetermined step width according to a hill-climbing method to search for the maximum power point, and generates a command value to maintain the maximum power point. The drive control unit generates a PWM signal based on the generated command value and carrier wave, and supplies the generated PWM signal to the gate terminal of the switching element Q11.

[0016] The inverter unit 20 is connected to the converter unit 10 via a DC bus Bd. A capacitor Cd is connected between the positive wiring and the negative wiring of the DC bus Bd. The capacitor Cd is a smoothing capacitor for stabilizing the voltage of the DC bus Bd. In the example shown in FIG. 1, an electrolytic capacitor is used as the capacitor Cd.

[0017] 1 shows an example in which the inverter unit 20 is configured as a full-bridge circuit. The full-bridge circuit includes a first arm in which two switching elements Q21 and Q22 are connected in series, and a second arm in which two switching elements Q23 and Q24 are connected in series. The first arm and the second arm are connected in parallel to the converter unit 10 and the capacitor Cd via a DC bus Bd. Diodes are connected in anti-parallel to the switching elements Q21-Q24 or formed in anti-parallel, similar to the switching element Q11 of the converter unit 10.

[0018] A drive control unit (not shown) of the power conversion device 1 drives the inverter unit 20 so that the voltage of the DC bus Bd maintains a target value. Specifically, the drive control unit generates a command value based on the difference between the measured value and the target value of the voltage of the DC bus Bd. The drive control unit generates a PWM signal based on the generated command value and a carrier wave, and supplies the generated PWM signal to the gate terminals of the switching elements Q21-Q24. The drive control unit can reduce the voltage of the DC bus Bd by increasing the duty ratio of the PWM signal, and can increase the voltage of the DC bus Bd by decreasing the duty ratio of the PWM signal.

[0019] Filter unit 30 attenuates harmonic components of the output voltage and output current of inverter unit 20 to make the waveforms of the output voltage and output current of inverter unit 20 closer to sine waves. Filter unit 30 is composed of an LC filter including AC reactors La1 and La2 and capacitor Cx.

[0020] 1 shows a power conversion device 1 that is connected to a power grid via a single-phase three-wire system. A U-phase electric wire (red) drawn from one end of a 200V winding on the consumer side of a transformer in the power grid, a W-phase electric wire (black) drawn from the other end of the 200V winding, and an O-phase electric wire (white) drawn from the midpoint of the 200V winding are connected to the grid wiring connection part 40.

[0021] The AC reactor La1 of the filter unit 30 is connected to a U-phase wiring that connects the midpoint of the first arm of the inverter unit 20 and a U-phase connection terminal of the system wiring connection unit 40. The AC reactor La2 of the filter unit 30 is connected to a W-phase wiring that connects the midpoint of the second arm of the inverter unit 20 and a W-phase connection terminal of the system wiring connection unit 40. The capacitor Cx is connected between the U-phase wiring and the W-phase wiring. The capacitor Cx reduces normal mode noise by passing normal mode noise. For example, a ceramic capacitor or a film capacitor can be used as the capacitor Cx.

[0022] In addition, since the power conversion device 1 handles 200V AC and not 100V AC, the O-phase electric wire (white) is not connected to the filter section 30 and the inverter section 20.

[0023] Figure 2 shows the basic waveforms of the PWM signals supplied to the gate terminals of switching elements Q11, Q21-Q24. In the PWM method, the current waveform flowing through the switching elements is a square wave. In the PWM method, the pulse period (operating frequency) is fixed and the pulse width varies. In the ZCS / ZVS method, the current waveform flowing through the switching elements is a half-wave rectified sine wave. In the ZCS / ZVS method, the on-time is fixed and the period varies.

[0024] In the PWM method, the current flowing through the switching element is controlled to a square wave shape, so abrupt current changes occur when the square wave rises or falls. This large current change strongly excites parasitic elements, generating high-frequency noise Nh of about 10 MHz to 30 MHz. In addition, the operating frequencies of converters and inverters are often set to about 20 kHz to 40 kHz so as not to fall into the audible range. In such cases, low-frequency noise Nl of about 20 kHz to 40 kHz is generated.

[0025] 1, an example is assumed in which the converter section 10, the inverter section 20, and the filter section 30 are mounted on one printed circuit board. A metal housing that houses the printed circuit board is earthed at least at one point to form a housing earth Fg. A stray capacitance Cf is formed between the wiring on the printed circuit board in the power conversion device 1 and the housing earth Fg.

[0026] As described above, high-frequency noise Nh and low-frequency noise Nl are generated due to switching of the switching elements Q11, Q21-Q24. These high-frequency noise Nh and low-frequency noise Nl pass through the stray capacitance Cf between the printed circuit board and the housing earth Fg. In the comparative example, as a measure against the high-frequency noise Nh and low-frequency noise Nl, a high-frequency common mode choke coil Lh1 and a low-frequency common mode choke coil Ll1 are wound between the harness (cable) connecting the solar cell 2 and the converter unit 10. Similarly, a high-frequency common mode choke coil Lh2 and a low-frequency common mode choke coil Ll2 are wound between the harness connecting the filter unit 30 and the system wiring connection unit 40.

[0027] A bypass capacitor Cy1 is connected between the positive wiring near the input terminal of the printed circuit board and the housing earth Fg, and between the negative wiring near the input terminal of the printed circuit board and the housing earth Fg. A bypass capacitor Cy2 is connected between the U-phase wiring near the output terminal of the printed circuit board and the housing earth Fg, and between the W-phase wiring near the output terminal of the printed circuit board and the housing earth Fg. The bypass capacitors Cy1 and CY2 pass common mode noise and reduce the common mode noise. For example, a ceramic capacitor or a film capacitor can be used for the capacitors Cy1 and Cy2.

[0028] 1, high-frequency noise Nh and low-frequency noise Nl generated by switching of switching elements Q11, Q21-Q24 are blocked by the high-frequency common mode choke coil Lh1 and low-frequency common mode choke coil Ll1 on the input side wound around the harness from flowing into the solar cell 2. Similarly, high-frequency noise Nh and low-frequency noise Nl are blocked by the high-frequency common mode choke coil Lh2 and low-frequency common mode choke coil Ll2 on the output side wound around the harness from flowing into the power system.

[0029] However, high-frequency noise Nh and low-frequency noise Nl flow as common-mode noise current between the wiring on the printed circuit board and the chassis earth Fg via stray capacitance Cf or bypass capacitors Cy1 and CY2. In the circuit configuration shown in Figure 1, the common-mode noise current flows to the vicinity of the input terminal and output terminal of the printed circuit board, forming a large current loop I1. This causes large conductive noise to propagate through the wiring on the printed circuit board. In addition, large radiated noise is emitted from the chassis and harness.

[0030] 3 is a diagram for explaining a first configuration example of the power conversion device 1 according to the first embodiment. In the first embodiment, instead of the harness-wrapped high-frequency common mode choke coil Lh and the low-frequency common mode choke coil Ll, a board-mounted wideband common mode choke coil Lc having wideband impedance characteristics corresponding to noise in a plurality of target bands is used. The plurality of target bands includes the operating frequency band of the switching element of about 20 kHz to 40 kHz described above, and a high-frequency noise band caused by a steep current change at the rising or falling edge of a rectangular wave of about 10 MHz to 30 MHz.

[0031] In the first embodiment, the wideband common mode choke coil Lc is mounted near the switching elements Q11, Q21-Q24, which are noise sources, to reduce the length of the current loop of the common mode noise. The wideband common mode choke coil Lc will be described in detail later.

[0032] 3, a first wideband common mode choke coil Lc1 is connected to the wiring between the DC reactor Ld and the switching element Q11 of the converter unit 10. A second wideband common mode choke coil Lc2 is connected to the wiring between the switching element Q11 of the converter unit 10 and the capacitor Cd of the DC bus Bd. The first wideband common mode choke coil Lc1 and the second wideband common mode choke coil Lc2 are mounted on a printed circuit board.

[0033] As a result, the propagation paths of high-frequency noise Nh and low-frequency noise Nl generated due to switching of the switching element Q11 of the converter unit 10 are limited to the range between the first wideband common mode choke coil Lc1 and the second wideband common mode choke coil Lc2. The length of the current loop I2 caused by the common mode noise flowing between the wiring of the converter unit 10 and the housing earth Fg via the stray capacitance Cf is shorter than the length of the current loop I1 shown in FIG. 1. When the length of the current loop is shortened, the amplification of the common mode noise can be suppressed. In particular, since the loop area is reduced, the radiation noise can be significantly reduced.

[0034] A third wideband common mode choke coil Lc3 is connected to the wiring between the capacitor Cd of the DC bus Bd and the switching elements Q21-Q24 of the inverter unit 20. A fourth wideband common mode choke coil Lc4 is connected to the wiring between the switching elements Q21-Q24 of the inverter unit 20 and the AC reactors La1 and La2. The third wideband common mode choke coil Lc3 and the fourth wideband common mode choke coil Lc4 are mounted on a printed circuit board.

[0035] As a result, the propagation paths of high-frequency noise Nh and low-frequency noise Nl generated due to the switching of switching elements Q21-Q24 of inverter unit 20 are limited to the range between third wideband common mode choke coil Lc3 and fourth wideband common mode choke coil Lc4. The length of current loop I3 formed by common mode noise current flowing between wiring of inverter unit 20 and housing earth Fg via stray capacitance Cf is shorter than the length of current loop I1 shown in FIG.

[0036] Fig. 4 is a diagram for explaining a first application example of the first configuration example of the power conversion device 1 according to the embodiment 1. In the first application example of the first configuration example shown in Fig. 4, a bypass capacitor Cx1 is connected between the positive and negative wiring between the DC reactor Ld and the switching element Q11 of the converter unit 10. A bypass capacitor Cx2 is connected between the positive and negative wiring between the switching element Q11 of the converter unit 10 and the capacitor Cd of the DC bus Bd.

[0037] A bypass capacitor Cx3 is connected between the positive and negative wiring between the capacitor Cd of the DC bus Bd and the switching elements Q21-Q24 of the inverter unit 20. A bypass capacitor Cx4 is connected between two wiring between the switching elements Q21-Q24 of the inverter unit 20 and the AC reactors La1 and La2.

[0038] By adding capacitors Cx1-Cx4, the propagation paths of normal mode noise and common mode noise can be further restricted.

[0039] Fig. 5 is a diagram for explaining a second application example of the first configuration example of the power conversion device 1 according to the first embodiment. In the second application example of the first configuration example shown in Fig. 5, a bypass capacitor Cy3a is connected between a positive wiring between the DC reactor Ld and the switching element Q11 of the converter unit 10 and a housing earth Fg. A bypass capacitor Cy3b is connected between a positive wiring between the switching element Q11 of the converter unit 10 and the capacitor Cd of the DC bus Bd and a housing earth Fg. A bypass capacitor Cy3c is connected between a negative wiring between the DC reactor Ld and the capacitor Cd of the DC bus Bd and a housing earth Fg.

[0040] A bypass capacitor Cy4a is connected between a wiring between the capacitor Cd of the DC bus Bd and the switching elements Q21-Q24 of the inverter unit 20 and a housing earth Fg. A bypass capacitor Cy4b is connected between a wiring between the switching elements Q21-Q24 of the inverter unit 20 and the AC reactors La1 and La2 and a housing earth Fg. A bypass capacitor Cx4 is connected between two wirings between the switching elements Q21-Q24 of the inverter unit 20 and the AC reactors La1 and La2.

[0041] By adding the capacitors Cy3a, Cy3b, Cy3c, Cy4a, Cy4b, and Cx4, it is possible to further restrict the propagation paths of common mode noise.

[0042] Fig. 6 is a diagram for explaining a second configuration example of the power conversion device 1 according to the embodiment 1. The second configuration example shown in Fig. 6 is a configuration in which the second wideband common mode choke coil Lc2 and the third wideband common mode choke coil Lc3 are omitted, compared to the first configuration example shown in Fig. 3.

[0043] In the second configuration example shown in Fig. 6, the propagation paths of high-frequency noise Nh and low-frequency noise Nl generated due to switching of the switching element Q11 of the converter unit 10 and the switching elements Q21-Q24 of the inverter unit 20 are limited to the range between the first wideband common mode choke coil Lc1 and the fourth wideband common mode choke coil Lc4. The length of the current loop I4 formed by the common mode noise current flowing through the stray capacitance Cf between the wiring on the printed circuit board and the housing earth Fg is shorter than the length of the current loop I1 shown in Fig. 1. That is, in the second configuration example shown in Fig. 6, the current loop is formed inside the DC reactor Ld and the AC reactor La, so that the length of the current loop is shorter than that of the comparative example shown in Fig. 1, and it is possible to suppress the propagation of noise outside the DC reactor Ld and the AC reactor La.

[0044] FIG. 7 is a diagram for explaining a configuration example of the power conversion device 1 according to the second embodiment. The power conversion device 1 according to the second embodiment is a DC output power conversion device 1 that does not include the inverter unit 20 and the filter unit 30. A DC load and a storage battery are connected to the DC output unit Do. In the power conversion device 1 according to the second embodiment shown in FIG. 7, a first wideband common mode choke coil Lc1 is connected to the wiring between the DC reactor Ld and the switching element Q11 of the converter unit 10, similar to the power conversion device 1 according to the first embodiment shown in FIG. 3. A second wideband common mode choke coil Lc2 is connected to the wiring between the switching element Q11 of the converter unit 10 and the capacitor Cd of the DC bus Bd.

[0045] Fig. 8 is a diagram for explaining a configuration example of a power conversion device 1 according to the third embodiment. The power conversion device 1 according to the third embodiment is a DC-input power conversion device 1 that does not include a converter unit 10 for PV. A converter that controls charging and discharging of a stationary type or an EV-mounted type storage battery, or a converter that controls the output of a fuel cell is connected to the DC input unit Din. Note that a plurality of converters each connected to a different distributed power source may be connected in parallel to the DC bus Bd.

[0046] In the power conversion device 1 according to the third embodiment shown in Fig. 8, similarly to the power conversion device 1 according to the first embodiment shown in Fig. 3, a third wideband common mode choke coil Lc3 is connected to the wiring between the capacitor Cd of the DC bus Bd and the switching elements Q21-Q24 of the inverter unit 20. A fourth wideband common mode choke coil Lc4 is connected to the wiring between the switching elements Q21-Q24 of the inverter unit 20 and the AC reactors La1 and La2.

[0047] 9 is a diagram showing a configuration example of a wideband common mode choke coil Lc according to an embodiment. The wideband common mode choke coil Lc includes a core material 50, a first conductive wire 51a, a second conductive wire 51b, a base portion 52, a first terminal portion 53a, a second terminal portion 53b, and fixing members 54a, 54b, and 54c. A nanocrystalline soft magnetic material is used for the core material 50. A core using a nanocrystalline soft magnetic material has flat characteristics with impedance over a wide band compared to a ferrite core.

[0048] The first conductor 51a and the second conductor 51b are wound around the left and right sides of the core material 50, respectively. At this time, the two conductors are wound in opposite directions. By winding in opposite directions, when a common mode current flows through the first conductor 51a and the second conductor 51b, the magnetic flux generated by the electromagnetic induction phenomenon caused by the first conductor 51a and the second conductor 51b, which form coils, is oriented in the same direction. As a result, the magnetic fluxes of the two conductors reinforce each other, enhancing their function as inductors. On the other hand, when a normal mode current flows through the first conductor 51a and the second conductor 51b, the magnetic fluxes generated by the electromagnetic induction phenomenon caused by the first conductor 51a and the second conductor 51b, which form coils, are oriented in opposite directions, and the magnetic fluxes of the two conductors cancel each other out, weakening their function as inductors.

[0049] The base portion 52 stacks the core material 50 around which the first conductive wire 51a and the second conductive wire 51b are wound. Two first terminal portions 53a connected to the first conductive wire 51a and two second terminal portions 53b connected to the second conductive wire 51b penetrate the base portion 52. The first fixing member 54a is a member for fixing the first conductive wire 51a to the first terminal portion 53a. The second fixing member 54b is a member for fixing the second conductive wire 51b to the second terminal portion 53b. The third fixing member 54c is a member for fixing the core material 50 to the base portion 52. In this manner, the wideband common mode choke coil Lc is mounted on the printed circuit board by four terminals.

[0050] Fig. 10 is a diagram showing the frequency-impedance characteristics of the wideband common mode choke coil Lc according to the embodiment. The wideband common mode choke coil Lc shown in Fig. 10 uses a core material 50 made of a nanocrystalline soft magnetic material with an outer diameter of 30 mm, an inner diameter of 20 mm, and a height (thickness) of 15 mm. Conductive wires 51a and 51b with a diameter of 1.8 mm are also used.

[0051] 10 shows frequency-impedance characteristics of five types of wideband common mode choke coils Lc in which the number of turns of the conductors 51a, 51b ranges from 1 T to 5 T. The wideband common mode choke coils Lc in which the number of turns ranges from 2 T to 5 T have an impedance of 10 Ω or more in the range of 10 kHz to 40 MHz.

[0052] The wideband common mode choke coil Lc, which has an impedance of 10Ω or more in the range of 10kHz to 40MHz, is a choke coil that can sufficiently reduce noise in the two target bands mentioned above (20kHz to 40kHz and 10MHz to 30MHz). Therefore, one wideband common mode choke coil Lc can replace both the high-frequency common mode choke coil Lh and the low-frequency common mode choke coil Ll.

[0053] As the number of turns is increased, the frequency-impedance characteristics change from a flat shape to a steep shape, so it is desirable to keep the number of turns within the range of about 2T to 5T.

[0054] As described above, according to this embodiment, it is possible to realize a power conversion device 1 in which common mode noise is reduced while reducing the space allocated to noise countermeasure components. That is, the measure of winding a core around the harness is no longer necessary, and the power conversion device 1 can be made low-profile and small-volume. In addition, since the high-frequency common mode choke coil Lh and the low-frequency common mode choke coil Ll can be integrated into one wideband common mode choke coil Lc, the mounting space for the common mode choke coil can be further reduced.

[0055] Furthermore, the board-mounted wideband common mode choke coil Lc according to this embodiment can be installed near the noise source (switching elements Q11, Q21-Q24). This makes it possible to directly suppress noise generated from the noise source. In contrast, when a harness-wrapped common mode choke coil is used, noise generated from the noise source is only secondarily suppressed outside the printed circuit board.

[0056] Furthermore, when a harness-wrapped common mode choke coil is used, the harness needs to be wound around the core, which requires labor costs. In contrast, when the board-mounted wideband common mode choke coil Lc according to the present embodiment is used, mass production is possible, and mass production can reduce manufacturing costs. As described above, when the wideband common mode choke coil Lc according to the present embodiment is used, the number of common mode choke coils to be installed can be halved, so that costs can also be reduced in terms of quantity.

[0057] Furthermore, when the wideband common mode choke coil Lc according to the present embodiment is used as described above, the length of the current loop can be shortened, and the noise level due to the common mode current can be reduced. In particular, since the loop area is reduced, the radiation noise can be significantly reduced.

[0058] The present disclosure has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present disclosure.

[0059] In the above embodiment, an example has been described in which the wideband common mode choke coil Lc according to the embodiment is used in the power conversion device 1. In this regard, the wideband common mode choke coil Lc according to the embodiment can be used in general electrical devices equipped with an inverter unit including a switching element controlled by a PWM method. Examples of electrical devices equipped with an inverter unit include refrigerators, air conditioners, vacuum cleaners, and washing machines. In these electrical devices, too, by connecting the wideband common mode choke coil Lc according to the embodiment near each of the front and rear stages of the switching element included in the inverter unit, it is possible to realize an electrical device in which common mode noise is reduced while reducing the space allocated to noise countermeasure components.

[0060] The embodiment may be specified by the following items.

[0061] [Item 1] a converter unit (10) capable of adjusting and outputting a voltage of DC power supplied from a DC power source (2); an inverter unit (20) that converts DC power output from the converter unit (10) into AC power; a common mode choke coil (Lc) mounted on a substrate and connected to wiring to which a switching element (Q11) included in the converter section (10) is connected and to wiring to which switching elements (Q21-Q24) included in the inverter section (20) are connected, The power conversion device (1) is characterized in that the common mode choke coil (Lc) has wideband impedance characteristics that can handle noise in a plurality of target bands generated from the switching elements (Q11, Q21-Q24). This makes it possible to realize a power conversion device (1) in which common mode noise is reduced while reducing the space required for noise suppression components. [Item 2] a smoothing capacitor (Cd) connected to a DC bus (Bd) connecting the converter unit (10) and the inverter unit (20), The converter section (10) further includes a DC reactor (Ld), The common mode choke coil (Lc1, LC2) is The power conversion device (1) according to item 1, characterized in that a wiring between the DC reactor (Ld) and a switching element (Q11) included in the converter section (10) and a wiring between the switching element (Q11) included in the converter section (10) and the smoothing capacitor (Cd) are connected to each other. This makes it possible to suppress common mode noise generated from the switching element (Q11) included in the converter section (10) within the range between the DC reactor (Ld) and the DC bus (Bd). [Item 3] a smoothing capacitor (Cd) connected to a DC bus (Bd) that connects the converter unit (10) and the inverter unit (20); a filter unit (30) for making the output waveform of the inverter unit (20) closer to a sine wave, The common mode choke coils (Lc3, Lc4) are The power conversion device (1) according to item 1, characterized in that a wiring between the smoothing capacitor (Cd) and a switching element (Q21-Q24) included in the inverter section (20), and a wiring between the switching elements (Q21-Q24) included in the inverter section (20) and AC reactors (La1, La2) included in the filter section (30) are connected to each other. This makes it possible to suppress common mode noise generated from the switching elements (Q21-Q24) included in the inverter section (20) within the range between the DC bus (Bd) and the AC reactors (La1, La2). [Item 4] a smoothing capacitor (Cd) connected to a DC bus (Bd) that connects the converter unit (10) and the inverter unit (20); a filter unit (30) for making the output waveform of the inverter unit (20) closer to a sine wave, The converter section (10) further includes a DC reactor (Ld), The common mode choke coils (Lc1, Lc4) are 2. The power conversion device (1) according to item 1, characterized in that a wiring between the DC reactor (Ld) and a switching element (Q11) included in the converter unit (10) and a wiring between switching elements (Q21-Q24) included in the inverter unit (20) and AC reactors (La1, La2) included in the filter unit (30) are connected to each other. This makes it possible to suppress common mode noise generated from the switching element (Q11) included in the converter section (10) and the switching elements (Q21-Q24) included in the inverter section (20) to within a range between the DC reactor (Ld) and the AC reactors (La1, La2). [Item 5] a smoothing capacitor (Cd) connected to a DC bus (Bd) that connects the converter unit (10) and the inverter unit (20); a filter unit (30) for making the output waveform of the inverter unit (20) closer to a sine wave, The converter section (10) further includes a DC reactor (Ld), The common mode choke coils (Lc1-Lc4) are 2. The power conversion device (1) according to item 1, characterized in that: a wiring between the DC reactor (Ld) and a switching element (Q11) included in the converter unit (10); a wiring between the switching element (Q11) included in the converter unit (10) and the smoothing capacitor (Cd); a wiring between the smoothing capacitor (Cd) and switching elements (Q21-Q24) included in the inverter unit (20); and a wiring between the switching elements (Q21-Q24) included in the inverter unit (20) and AC reactors (La1, La2) included in the filter unit (30). According to this, common mode noise generated from the switching element (Q11) included in the converter unit (10) can be suppressed to a range between the DC reactor (Ld) and the DC bus (Bd), and common mode noise generated from the switching elements (Q21-Q24) included in the inverter unit (20) can be suppressed to a range between the DC bus (Bd) and the AC reactors (La1, La2). [Item 6] The power conversion device (1) according to item 2 or 5, further comprising bypass capacitors (Cx1, Cx2) connected between positive and negative wiring between the DC reactor (Ld) and a switching element (Q11) included in the converter unit (10) and between positive and negative wiring between the switching element (Q11) included in the converter unit (10) and the smoothing capacitor (Cd), respectively. This makes it possible to further suppress normal mode noise and common mode noise generated from the switching element (Q11) included in the converter section (10). [Item 7] 6. The power conversion device (1) according to item 3 or 5, further comprising bypass capacitors (Cx3, Cx4) connected between positive and negative wiring between the smoothing capacitor (Cd) and a switching element (Q21-Q24) included in the inverter unit (20) and between two wirings between the switching elements (Q21-Q24) included in the inverter unit (20) and AC reactors (La1, La2) included in the filter unit (30). This makes it possible to further suppress normal mode noise and common mode noise generated from switching elements (Q21-Q24) included in inverter section (20). [Item 8] the inverter further includes bypass capacitors (Cy3a-Cy3c) connected between a positive wiring between the DC reactor (Ld) and a switching element (Q11) included in the converter unit (10) and a housing earth, between a positive wiring between the switching element (Q11) included in the converter unit (10) and the smoothing capacitor (Cd) and the housing earth, and between a negative wiring between the DC reactor (Ld) and the smoothing capacitor (Cd) and the housing earth, 6. The power conversion device (1) according to item 2 or 5. This makes it possible to further suppress the common mode noise generated from the switching element (Q11) included in the converter section (10). [Item 9] 6. The power conversion device (1) according to item 3 or 5, further comprising bypass capacitors (Cy4a, Cy4b) connected between a wiring between the smoothing capacitor (Cd) and a switching element (Q21-Q24) included in the inverter unit (20) and a housing earth, and between a wiring between a switching element (Q21-Q24) included in the inverter unit (20) and an AC reactor (La1, La2) included in the filter unit (30) and the housing earth, respectively. This makes it possible to further suppress common mode noise generated from switching elements (Q21-Q24) included in inverter section (20). [Item 10] 10. The power converter (1) according to any one of items 1 to 9, wherein the common mode choke coil (Lc1-Lc4) has an impedance of 10Ω or more in a range of 10 kHz to 40 MHz. This makes it possible to reduce noise in the two target bands generated by the switching element (Q11) included in the converter section (10) and the switching elements (Q21-Q24) included in the inverter section (20). [Explanation of symbols]

[0062] REFERENCE SIGNS LIST 1 power conversion device, 2 solar cell, 10 converter section, 20 inverter section, 30 filter section, 40 system wiring connection section, Bd DC bus, Ld DC reactor, La1, La2 AC reactor, Lh1, Lh2 high-frequency common mode choke coil, Ll1, Ll2 low-frequency common mode choke coil, Lc1-Lc4 wideband common mode choke coil, D11 diode, Q11, Q21, Q22, Q23, Q24 switching element, Cd, Cx, Cy capacitor, Cf stray capacitance, Fg housing earth, Din DC input section, Do DC output section, 50 core material, 51a first conductor, 51b second conductor, 52 base section, 53a first terminal section, 53b second terminal section, 54a-54c Fixing members.

Claims

1. a converter unit capable of adjusting and outputting a voltage of DC power supplied from a DC power source; an inverter unit that converts the DC power output from the converter unit into AC power; a wiring to which a switching element included in the converter unit is connected, and a substrate-mounted common mode choke coil connected to the wiring to which a switching element included in the inverter unit is connected, The converter unit further includes a DC reactor, The common mode choke coil comprises: A power conversion device connected to wiring between the DC reactor and a switching element included in the converter unit, and characterized in that it has wideband impedance characteristics that correspond to noise in a plurality of target bands generated from the switching element included in the converter unit.

2. 2. The power conversion device according to claim 1, further comprising a bypass capacitor connected between positive and negative wiring between the DC reactor and a switching element included in the converter unit.

3. further comprising bypass capacitors connected between a positive wiring between the DC reactor and a switching element included in the converter unit and a housing earth, between a positive wiring between the switching element included in the converter unit and the inverter unit and the housing earth, and between a negative wiring between the DC reactor and the inverter unit and the housing earth, 2. The power conversion device according to claim 1 .

4. 4. The power conversion device according to claim 1, wherein the common mode choke coil has an impedance of 10 Ω or more in a range of 10 kHz to 40 MHz.

5. a converter unit capable of adjusting and outputting a voltage of DC power supplied from a DC power source; an inverter unit that converts the DC power output from the converter unit into AC power; a common mode choke coil mounted on a substrate, the common mode choke coil being connected to wiring to which a switching element included in the converter unit is connected and to wiring to which a switching element included in the inverter unit is connected; a smoothing capacitor connected to a DC bus that connects the converter unit and the inverter unit, The converter unit further includes a DC reactor, The common mode choke coil comprises: a wiring between the DC reactor and a switching element included in the converter unit, and a wiring between the switching element included in the converter unit and the smoothing capacitor, A power conversion device having wideband impedance characteristics corresponding to noise in a plurality of target bands generated from a switching element included in the converter section.

6. a converter unit capable of adjusting and outputting a voltage of DC power supplied from a DC power source; an inverter unit that converts the DC power output from the converter unit into AC power; a common mode choke coil mounted on a substrate, the common mode choke coil being connected to wiring to which a switching element included in the converter unit is connected and to wiring to which a switching element included in the inverter unit is connected; a smoothing capacitor connected to a DC bus connecting the converter unit and the inverter unit; a filter unit for making the output waveform of the inverter unit closer to a sine wave, The common mode choke coil comprises: a wiring between the smoothing capacitor and a switching element included in the inverter unit, and a wiring between the switching element included in the inverter unit and an AC reactor included in the filter unit, A power conversion device having wideband impedance characteristics corresponding to noise in a plurality of target bands generated from switching elements included in the inverter unit.

7. a converter unit capable of adjusting and outputting a voltage of DC power supplied from a DC power source; an inverter unit that converts the DC power output from the converter unit into AC power; a common mode choke coil mounted on a substrate, the common mode choke coil being connected to wiring to which a switching element included in the converter unit is connected and to wiring to which a switching element included in the inverter unit is connected; a smoothing capacitor connected to a DC bus connecting the converter unit and the inverter unit; a filter unit for making the output waveform of the inverter unit closer to a sine wave, The converter unit further includes a DC reactor, The common mode choke coil comprises: a wiring between the DC reactor and a switching element included in the converter unit, and a wiring between a switching element included in the inverter unit and an AC reactor included in the filter unit, A power conversion device having wideband impedance characteristics corresponding to noise in a plurality of target bands generated from switching elements included in the converter section and switching elements included in the inverter section.

8. A converter unit capable of adjusting and outputting a voltage of DC power supplied from a DC power source; an inverter unit that converts the DC power output from the converter unit into AC power; a common mode choke coil mounted on a substrate, the common mode choke coil being connected to wiring to which a switching element included in the converter unit is connected and to wiring to which a switching element included in the inverter unit is connected; a smoothing capacitor connected to a DC bus connecting the converter unit and the inverter unit; a filter unit for making the output waveform of the inverter unit closer to a sine wave, The converter unit further includes a DC reactor, The common mode choke coil comprises: a wiring between the DC reactor and a switching element included in the converter section, a wiring between the switching element included in the converter section and the smoothing capacitor, a wiring between the smoothing capacitor and a switching element included in the inverter section, and a wiring between the switching element included in the inverter section and the AC reactor included in the filter section, A power conversion device having wideband impedance characteristics corresponding to noise in a plurality of target bands generated from switching elements included in the converter section and switching elements included in the inverter section.

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