Power conversion system

Abstract

This invention provides a technique for more effectively suppressing radiated noise from a power conversion device. One embodiment of the power conversion device (1) includes: a rectifier circuit (10) that converts AC power input from a commercial AC power source (PS) into DC power; a smoothing capacitor (Cdc) disposed in a path connecting the positive (PL) and negative (NL) lines of the DC power output from the rectifier circuit (10); an inverter circuit (30) connected in parallel with the smoothing capacitor (Cdc) to the positive (PL) and negative (NL) lines, and converting the smoothed DC power (Cdc) into a specified AC power output by switching semiconductor elements (S1-S6); and a noise suppression capacitor (C1) disposed in a path connecting the positive (PL) and negative (NL) lines of the rectifier circuit (10) and the smoothing capacitor (Cdc).

Description

Technical Field

[0001] This invention relates to power conversion devices. Background Technology

[0002] Previously, techniques for suppressing radiated noise in power conversion devices based on the switching operation of semiconductor elements such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors) were known (e.g., Patent Document 1).

[0003] <Prior art documents>

[0004] <Patent Documents>

[0005] Patent Document 1: Japanese Invention Patent No. 6041862 Summary of the Invention

[0006] <Problem to be solved by this invention>

[0007] However, high-frequency (e.g., above 10MHz) noise components generated by semiconductor elements such as IGBTs are converted from the normal mode (differential mode) to the common mode and transmitted to the input side in the circuit of the power conversion device. Furthermore, they flow out from the power conversion device to the input side and ultimately become high-frequency common-mode current as a source of radiated noise.

[0008] However, during this transmission process, even if high-frequency noise components can be suppressed (attenuated) using conventional suppression methods, radiated noise may become relatively high depending on the circuit configuration and construction of the power conversion device. For example, there may be a path with relatively more high-frequency noise components adjacent to the input side path where high-frequency noise components are attenuated and become relatively less during transmission. In this case, noise components from the path with relatively less high-frequency noise components on the input side may be induced in the path with relatively more high-frequency noise components, resulting in relatively high radiated noise. Therefore, conventional suppression methods may not be able to adequately suppress radiated noise.

[0009] Therefore, in view of the above-mentioned issues, the object of the present invention is to provide a technique that can more appropriately suppress radiated noise of power conversion devices.

[0010] <Methods for solving problems>

[0011] To achieve the above objectives, in one embodiment of the present invention, a power conversion device is provided, comprising:

[0012] A rectifier circuit converts externally input alternating current (AC) into direct current (DC).

[0013] A smoothing capacitor is provided in the path connecting the positive and negative lines of the DC current output from the aforementioned rectifier circuit.

[0014] A power conversion circuit, connected in parallel with the aforementioned smoothing capacitor to the aforementioned positive and negative terminals, converts the smoothed direct current (DC) through the smoothing capacitor into a predetermined alternating current (AC) and outputs it via the switching action of a semiconductor element; and

[0015] The first inter-line capacitor is disposed in the path of the positive line and the negative line connecting the rectifier circuit and the smoothing capacitor.

[0016] <The Effects of the Invention>

[0017] According to the above embodiments, the radiated noise of the power conversion device can be suppressed more appropriately. Attached Figure Description

[0018] Figure 1 This is a circuit diagram showing the first example of a power conversion device.

[0019] Figure 2 This is a circuit diagram showing a second example of a power conversion device.

[0020] Figure 3 This is a circuit diagram showing the third example of a power conversion device.

[0021] Figure 4 This is a circuit diagram showing the fourth example of a power conversion device.

[0022] Figure 5 This is a circuit diagram showing the fifth example of a power conversion device.

[0023] Figure 6 This is a circuit diagram showing the sixth example of a power conversion device.

[0024] Figure 7 This is a circuit diagram showing the seventh example of a power conversion device.

[0025] Figure 8 This is a circuit diagram showing the eighth example of a power conversion device.

[0026] Figure 9 This is a circuit diagram showing the ninth example of a power conversion device.

[0027] Figure 10 This is a graph showing the spectrum of radiated noise of the power conversion device of the comparative example and the power conversion device of the embodiment. Detailed Implementation

[0028] The embodiments will now be described with reference to the accompanying drawings.

[0029] [The First Example of an Electricity Conversion Device]

[0030] First, refer to Figure 1 The first example of the power conversion device 1 of this embodiment will be described.

[0031] Figure 1 This is a circuit diagram showing a first example of the power conversion device 1 according to this embodiment.

[0032] The power conversion device 1 uses the three-phase AC power input from the commercial AC power source PS (R phase, S phase, and T phase) to generate the specified three-phase AC power and supply it to the motor M.

[0033] It should be noted that the power conversion device 1 includes internally conductive terminals Ein and Eout. Terminal Ein is connected to the grounding wire of the commercial AC power supply PS, and terminal Eout is connected to the reference potential of the motor M, so that the motor M and the commercial AC power supply PS are grounded together.

[0034] like Figure 1 As shown, the power conversion device 1 includes a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, and a noise suppression capacitor C1.

[0035] The rectifier circuit 10 rectifies the three-phase AC power input from the commercial AC power supply PS (R-phase, S-phase, and T-phase) and outputs the specified DC power to the smoothing circuit 20 via the positive line PL and the negative line NL.

[0036] The rectifier circuit 10 is, for example, a bridged connection of six diodes D1 to D6. Specifically, it is a bridged full-wave rectifier circuit in which the upper and lower bridge arms of diodes D1, D4, D2, D5, and D3, D6 are connected in parallel, and three-phase AC power of phase R, phase S, and phase T is input from the midpoint of each upper and lower bridge arm.

[0037] The smoothing circuit 20 suppresses and smooths the pulsation of the DC power output from the self-rectifier circuit 10 and the DC power regenerated by the self-inverter circuit 30.

[0038] The smoothing circuit 20 includes a smoothing capacitor Cdc.

[0039] The smoothing capacitor Cdc is connected in parallel with the rectifier circuit 10 and the inverter circuit 30 in the path connecting the positive line PL and the negative line NL. The smoothing capacitor Cdc appropriately smooths the DC output of the rectifier circuit 10 and the inverter circuit 30 by repeatedly charging and discharging.

[0040] There can be one smoothing capacitor Cdc. Alternatively, multiple smoothing capacitors Cdc can be configured, and these multiple smoothing capacitors Cdc can be connected in parallel or in series between the positive line PL and the negative line NL. The same applies to the cases in examples 2 to 9 described below.

[0041] It should be noted that the smoothing circuit 20 may include a DC reactor. In this case, the DC reactor is connected in series, for example, on the positive line PL between the rectifier circuit 10 and the smoothing capacitor Cdc. The same applies to the cases described below in examples two through nine. The DC reactor is connected to improve the input power factor, reduce higher harmonics, and stabilize the smoothing circuit voltage, etc.

[0042] Inverter circuit 30 (an example of a power conversion circuit) and smoothing circuit 20 (smoothing capacitor Cdc) are connected in parallel to the positive line PL and the negative line NL. Inverter circuit 30 converts the direct current supplied from the smoothing circuit 20 via the positive line PL and the negative line NL into three-phase alternating current (U-phase, V-phase, and W-phase) with a specified frequency and voltage through the switching operation of semiconductor elements S1 to S6, and outputs it to motor M. Semiconductor elements S1 to S6 are, for example, IGBTs and MOSFETs.

[0043] The inverter circuit 30 is configured as a bridge circuit in which the upper and lower bridge arms (switching bridge arms) of semiconductor elements S1, S4, S2, S5, and S3, S6 are connected in parallel between the positive line PL and the negative line NL. Furthermore, in the inverter circuit 30, output lines for the U-phase, V-phase, and W-phase are drawn from the connection point (midpoint) of the upper and lower bridge arms of semiconductor elements S1, S4, S2, S5, and S3, S6. Additionally, return diodes are connected in parallel with semiconductor elements S1 to S6, respectively.

[0044] A noise suppression capacitor C1 (an example of a first-line capacitor) is positioned in the path connecting the positive line PL and the negative line NL between the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc). The noise suppression capacitor C1 can be, for example, a multilayer ceramic capacitor with relatively small capacitance. Alternatively, there can be only one noise suppression capacitor C1. Multiple noise suppression capacitors C1 can also be configured, and these multiple noise suppression capacitors C1 can be connected in parallel or in series between the positive line PL and the negative line NL. The same applies to the cases in the second to ninth examples described below.

[0045] Additionally, the power conversion device 1 may include a buffer capacitor (hereinafter referred to as a "diode buffer capacitor") for protecting diodes D1 to D6 and a buffer capacitor (hereinafter referred to as a "switch buffer capacitor") for protecting semiconductor elements S1 to S6. The same applies to the second to ninth examples described below.

[0046] A diode snubber capacitor is disposed in the path connecting the positive line PL and the negative line NL between the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc). For example, the diode snubber capacitor can be disposed in the path connecting the positive line PL and the negative line NL between the noise suppression capacitor C1 and the smoothing capacitor Cdc. That is, the diode snubber capacitor is connected in parallel with the rectifier circuit 10 between the positive line PL and the negative line NL adjacent to the rectifier circuit 10. The diode snubber capacitor can be, for example, a thin-film capacitor with relatively large capacitance.

[0047] The switching snubber capacitor is positioned in the path connecting the positive line PL and the negative line NL between the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30. That is, the switching snubber capacitor is connected in parallel with the inverter circuit 30 between the positive line PL and the negative line NL adjacent to the inverter circuit 30. The switching snubber capacitor can be, for example, a film capacitor with relatively large capacitance.

[0048] The rectifier circuit 10 and the inverter circuit 30, together with other necessary components, constitute the PIM (Power Integrated Module) 400.

[0049] The PIM400 includes AC input terminals R, S, T, AC output terminals U, V, W, positive output terminal P0, positive input terminal P1, and negative terminal N.

[0050] AC input terminals R, S, and T are externally connected to the R-phase, S-phase, and T-phase input lines of the commercial AC power supply PS, respectively. Thus, the three-phase AC power input from the commercial AC power supply PS is supplied to the rectifier circuit 10.

[0051] AC output terminals U, V, and W are internally connected to the output lines of phases U, V, and W of the inverter circuit, respectively, and externally connected to the input terminals of phases U, V, and W of the motor M via cables, etc. Thus, three-phase AC power is supplied from the power conversion device 1 (PIM400) to the motor M, thereby driving the motor M.

[0052] The positive output terminal P0 leads the positive line PL from the output terminal of the positive side of the rectifier circuit 10 to the outside of the PIM400.

[0053] The positive input terminal P1 leads the positive line PL from the positive input terminal of the inverter circuit 30 to the outside of the PIM400.

[0054] The negative terminal N leads the negative line NL from the output terminal on the negative side of the rectifier circuit 10 and the input terminal on the negative side of the inverter circuit 30 to the outside of the PIM400. In other words, unlike the positive line PL, in the negative line NL, the negative output terminal of the rectifier circuit 10 and the negative input terminal of the inverter circuit 30 are shared at the negative terminal N. Therefore, compared to the case where the rectifier circuit 10 and the inverter circuit 30 each have their own separate negative output and negative input terminals, the PIM400 can be miniaturized, achieving a reduction in mounting space based on the shared wiring of the substrate connected to the PIM400.

[0055] The smoothing capacitor Cdc is included (mounted) on the capacitor substrate 200.

[0056] The capacitor substrate 200 includes a positive input terminal Pc0, a positive output terminal Pc1, and a negative terminal Nc.

[0057] The positive input terminal Pc0 is connected to the positive terminal of the smoothing capacitor Cdc via a wiring pattern on the capacitor substrate 200, and is also connected to the positive line PL on the output side of the rectifier circuit 10, which is disposed outside the capacitor substrate 200 (e.g., on the main substrate). Thus, the positive terminal of the smoothing capacitor Cdc is connected to the positive line PL on the output side of the rectifier circuit 10.

[0058] The positive output terminal Pc1 is connected to the positive terminal of the smoothing capacitor Cdc via a wiring pattern on the capacitor substrate 200, and is also connected to the positive line PL on the input side of the inverter circuit 30, which is disposed outside the capacitor substrate 200 (e.g., on the main substrate). Thus, the positive terminal of the smoothing capacitor Cdc is connected to the positive line PL on the input side of the inverter circuit 30.

[0059] The negative terminal Nc is connected to the negative terminal of the smoothing capacitor Cdc via a wiring pattern on the capacitor substrate 200, and is also connected to the negative line NL of the negative terminal N connected to the PIM400, which is disposed outside the capacitor substrate 200 (e.g., on the main substrate). Thus, the negative terminal of the smoothing capacitor Cdc is connected to the negative line NL of the output side of the rectifier circuit 10 and the input side of the inverter circuit 30. In other words, unlike the positive line PL, in the negative line NL, the negative input terminal connected to the negative line NL of the output side of the rectifier circuit 10 and the negative output terminal connected to the negative line NL of the input side of the inverter circuit 30 are shared in the negative terminal Nc. Therefore, compared to the case where the negative input terminal and the negative output terminal are provided separately, the mounting area of ​​the terminals on the capacitor substrate 200 can be reduced.

[0060] The positive electrode line PL includes positive electrode lines PL11 to PL14.

[0061] The positive line PL11 connects the positive output terminal of the rectifier circuit 10 and the positive output terminal P0 inside the PIM400.

[0062] The positive line PL12 connects the positive output terminal P0 of the PIM400 and the positive input terminal Pc0 of the capacitor substrate 200 externally (e.g., on the main substrate). Additionally, a surge current prevention relay can be configured in the positive line PL12.

[0063] The positive line PL13 connects the positive output terminal Pc1 of the capacitor substrate 200 and the positive input terminal P1 of the PIM400 on the outside of the PIM400 (e.g., on the main substrate).

[0064] The positive line PL14 connects the positive input terminal of the inverter circuit 30 and the positive input terminal P1 inside the PIM400.

[0065] The negative electrode line NL includes negative electrode lines NL11 to NL13.

[0066] The negative line NL11 connects the output of the rectifier circuit 10 and the input of the inverter circuit 30 inside the PIM400. That is, unlike the positive line PL, in the negative line NL, the output of the rectifier circuit 10 and the input of the inverter circuit 30 are connected internally within the PIM400, and the negative line NL is shared between the output side of the rectifier circuit 10 and the input side of the inverter circuit 30.

[0067] Inside the PIM400, negative line NL12 connects negative terminal N and negative line NL11 in parallel with rectifier circuit 10 and inverter circuit 30. Thus, negative terminal N is connected to the output terminal of the negative side of rectifier circuit 10 and the input terminal of the negative side of inverter circuit 30 through negative lines NL12 and NL11.

[0068] The negative electrode line NL13 connects the negative terminal N of PIM400 and the negative terminal Nc of capacitor substrate 200 on the outside of PIM400 (e.g., on the main substrate).

[0069] As described above, the negative output terminal of the rectifier circuit 10 and the negative input terminal of the inverter circuit 30 are shared at the negative terminal N. Therefore, the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc, and the negative line NL between the inverter circuit 30 and the smoothing capacitor Cdc, are shared at the negative lines NL12 and NL13, which include the negative terminals N and Nc.

[0070] The noise suppression capacitor C1 is disposed outside the PIM400 (e.g., on the main substrate) in the path connecting the positive line PL12 and the negative line NL13.

[0071] The capacitance of the noise suppression capacitor C1 can be, for example, a value larger than the junction capacitance of diodes D1 to D6. Alternatively, the capacitance of the noise suppression capacitor C1 can be, for example, a value lower than the capacitance of a diode buffer capacitor, which requires a relatively large capacitance to suppress surge voltage. The same applies to the cases in examples two through nine described later.

[0072] The diode snubber capacitor can be disposed, for example, outside the PIM400 (e.g., on the main substrate) in the path of the positive line PL12 and the negative line NL13 connecting the noise suppression capacitor C1 and the smoothing capacitor Cdc.

[0073] The switching snubber capacitor can be placed, for example, in the path of the positive line PL13 and the negative line NL13 connecting the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30.

[0074] Thus, in this example, a noise suppression capacitor C1 is set.

[0075] For example, high-frequency noise components are generated during the switching operations of semiconductor elements S1 to S6 in inverter circuit 30. These high-frequency noise components, originating from semiconductor elements S1 to S6, are converted from normal mode to common mode and propagate through the circuit in the order of inverter circuit 30, smoothing capacitor Cdc, and rectifier circuit 10, ultimately becoming a high-frequency common-mode current that serves as a source of radiated noise. During this propagation process, the high-frequency noise components typically attenuate. Therefore, for high-frequency noise components, it is expected that the high-frequency noise components in the path from inverter circuit 30 through smoothing capacitor Cdc to rectifier circuit 10 will be smaller in the portion of the path relatively closer to inverter circuit 30 compared to the portion relatively closer to rectifier circuit 10.

[0076] On the other hand, in this example, as described above, the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc is shared with the negative line NL12 and NL13 between the inverter circuit 30 and the smoothing capacitor Cdc, including the negative terminals N and Nc. Therefore, sometimes the path between the inverter circuit 30 and the smoothing capacitor Cdc, which has relatively high high-frequency noise components, is physically close to the path between the rectifier circuit 10 and the smoothing capacitor Cdc, which is expected to have relatively low high-frequency noise components. In this case, high-frequency noise components may be induced from the path between the rectifier circuit 10 and the smoothing capacitor Cdc through electrostatic induction or electromagnetic induction. As a result, the high-frequency noise components at the output of the rectifier circuit 10, which were originally expected to attenuate and become relatively small, become relatively large, thus potentially increasing the high-frequency noise components flowing from the rectifier circuit 10 to the commercial AC power supply PS (system side). Furthermore, the radiated noise may become relatively large due to components above 30MHz in the high-frequency noise flowing to the system side. In particular, if the voltage of the high-frequency components between the positive line PL and the negative line NL at the output of the rectifier circuit 10 is at the same level as, or higher than, the voltage of the high-frequency components between the positive line PL and the negative line NL at the input of the inverter circuit 30, the radiated noise becomes very large.

[0077] It should be noted that the high-frequency voltage between the positive line PL and the negative line NL at the output terminal of the rectifier circuit 10 is equivalent to the high-frequency voltage between the positive output terminal P0 and the negative terminal N. Furthermore, the high-frequency voltage between the positive line PL and the negative line NL at the input terminal of the inverter circuit 30 is equivalent to the high-frequency voltage between the positive input terminal P1 and the negative terminal N.

[0078] In contrast, in this example, as described above, a noise suppression capacitor C1 is placed in the path connecting the positive line PL and the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc. In particular, since the rectifier circuit 10, centered around diodes D1 to D6, does not require a drive circuit, there is ample space for the noise suppression capacitor C1. Therefore, its size (capacitance) is not limited, and the noise suppression capacitor C1 can be placed closer to the positive output terminal P0 and the negative terminal N corresponding to the output terminal of the rectifier circuit 10. Therefore, by bypassing the path containing the noise suppression capacitor C1, which has low impedance characteristics relative to high frequencies, high-frequency noise components in the path between the rectifier circuit 10 and the smoothing capacitor Cdc can be fed back to the inverter circuit 30. Thus, even in circuit configurations where the high-frequency noise components in the path between the rectifier circuit 10 and the smoothing capacitor Cdc relatively increase due to induction from other paths, high-frequency noise components flowing to the system side can be suppressed, thereby suppressing radiated noise.

[0079] [Second example of an electric power conversion device]

[0080] Next, refer to Figure 2 Hereinafter, a second example of the power conversion device 1 of this embodiment will be described. The description will focus on the parts that differ from the first example described above, and sometimes simplifications or omissions will be made regarding content that is the same as or equivalent to the first example described above.

[0081] Figure 2 This is a circuit diagram showing a second example of the power conversion device 1 according to this embodiment.

[0082] like Figure 2 As shown, similar to the first example above, the power conversion device 1 includes a rectifier circuit 10, a smoothing circuit 20, an inverter circuit 30, and a noise suppression capacitor C1.

[0083] Unlike the first example above, the rectifier circuit 10 and the inverter circuit 30, together with other necessary components, form separate modules (diode module 100 and inverter module 300).

[0084] The diode module 100 includes AC input terminals R, S, T, a positive output terminal P0, and a negative output terminal N0.

[0085] Except that the AC input terminals R, S, T and the positive output terminal P0 are located in the diode module 100 instead of PIM400, it has the same function as the first example described above.

[0086] The negative output terminal N0 leads the negative line NL out to the outside of the diode module 100 from the output terminal on the negative side of the rectifier circuit 10.

[0087] The inverter module 300 includes AC output terminals U, V, W, positive input terminal P1, and negative input terminal N1.

[0088] In addition to replacing PIM400 by placing the AC output terminals U, V, W and the positive input terminal P1 outside the inverter module 300, it has the same function as the first example above.

[0089] The negative input terminal N1 leads the negative line NL from the negative side input terminal of the inverter circuit 30 to the outside of the inverter module 300.

[0090] Similar to the first example above, the smoothing capacitor Cdc is included (mounted) on the capacitor substrate 200.

[0091] Similar to the first example above, the positive electrode line PL includes positive electrode lines PL11 to PL14.

[0092] The negative electrode line NL includes negative electrode lines NL21 to NL24.

[0093] The negative line NL21 connects the output terminal of the negative side of the rectifier circuit 10 and the negative output terminal N0 of the diode module 100 inside the diode module 100.

[0094] The negative line NL22 connects the negative output terminal N0 of the diode module 100 and the negative terminal Nc of the capacitor substrate 200 outside the diode module 100 (e.g., on the main substrate).

[0095] The negative line NL23 connects the negative terminal Nc of the capacitor substrate 200 and the negative input terminal N1 of the inverter module 300 outside the inverter module 300 (e.g., on the main substrate).

[0096] Negative line NL24 connects the negative input terminal of inverter circuit 30 and the negative input terminal N1 of inverter module 300 inside inverter module 300.

[0097] The noise suppression capacitor C1 is disposed outside the diode module 100 and the inverter module 300 (e.g., on the main substrate) in the path connecting the positive line PL12 and the negative line NL22.

[0098] The diode buffer capacitor can be, for example, positioned in the path of the positive line PL12 and the negative line NL22 connecting the noise suppression capacitor C1 and the smoothing circuit 20 (smoothing capacitor Cdc).

[0099] The switching snubber capacitor can be placed, for example, in the path of the positive line PL13 and the negative line NL23 connecting the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30.

[0100] Thus, in this example, similar to the first example above, a noise suppression capacitor C1 is set.

[0101] In this example, the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc shares the same negative terminal Nc as the negative line NL between the inverter circuit 30 and the smoothing capacitor Cdc. Therefore, similar to the first example described above, the path between the inverter circuit 30 and the smoothing capacitor Cdc is sometimes physically close to the path between the rectifier circuit 10 and the smoothing capacitor Cdc. As a result, the high-frequency noise component at the output of the rectifier circuit 10 may become relatively large, leading to a relative increase in radiated noise from components above 30MHz flowing towards the system side. Specifically, if the voltage of the high-frequency component between the positive line PL and the negative line NL at the output of the rectifier circuit 10 is at the same level as, or higher than, the voltage of the high-frequency component between the positive line PL and the negative line NL at the input of the inverter circuit 30, the radiated noise becomes very large.

[0102] It should be noted that the high-frequency voltage between the positive line PL and the negative line NL at the output terminal of the rectifier circuit 10 is equivalent to the high-frequency voltage between the positive output terminal P0 and the negative output terminal N0. Furthermore, the high-frequency voltage between the positive line PL and the negative line NL at the input terminal of the inverter circuit 30 is equivalent to the high-frequency voltage between the positive input terminal P1 and the negative input terminal N1.

[0103] In contrast, in this example, similar to the first example described above, a noise suppression capacitor C1 is placed in the path between the positive line PL and the negative line NL connecting the rectifier circuit 10 and the smoothing capacitor Cdc. In particular, since the rectifier circuit 10, centered around diodes D1 to D6, does not require a drive circuit, there is ample space for the noise suppression capacitor C1. Therefore, regardless of its size (capacitance), the noise suppression capacitor C1 can be placed closer to the positive output terminal P0 and the negative output terminal N0 corresponding to the output terminals of the rectifier circuit 10. Thus, by bypassing the path containing the noise suppression capacitor C1, which has low impedance characteristics relative to high frequencies, high-frequency noise components in the path between the rectifier circuit 10 and the smoothing capacitor Cdc can be fed back to the inverter circuit 30. Therefore, even in circuit configurations where the high-frequency noise components in the path between the rectifier circuit 10 and the smoothing capacitor Cdc relatively increase due to induction from other paths, high-frequency noise components flowing to the system side can be suppressed, thereby suppressing radiated noise.

[0104] [The Third Example of an Electricity Conversion Device]

[0105] Next, refer to Figure 3 The third example of the power conversion device 1 of this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example, etc., and sometimes the description of the same or corresponding content as the first example, etc. will be simplified or omitted.

[0106] Figure 3 This is a circuit diagram showing a third example of the power conversion device 1 according to this embodiment.

[0107] like Figure 3 As shown, the power conversion device 1 differs from the first example above in that it adds a noise suppression capacitor C2.

[0108] The noise suppression capacitor C2 (an example of a second line capacitor) is disposed in the path of the positive line PL and the negative line NL connecting the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30. Specifically, the noise suppression capacitor C2 is disposed in the path of the positive line PL13 and the negative line NL13 connecting the smoothing capacitor Cdc and the inverter circuit 30.

[0109] The noise suppression capacitor C2 can be, for example, a multilayer ceramic capacitor with a relatively small capacitance, similar to the noise suppression capacitor C1. Furthermore, multiple noise suppression capacitors C2 can be configured, and these multiple noise suppression capacitors C2 can be connected in parallel between the positive line PL and the negative line NL, or connected in series. Additionally, the electrostatic capacitance of the noise suppression capacitor C2 can be, for example, a value larger than the output capacitance of semiconductor elements S1 to S6, i.e., the electrostatic capacitance between the main electrodes (e.g., between the collector and emitter of an IGBT) when DC current is applied. Furthermore, the electrostatic capacitance of the noise suppression capacitor C2 can be, for example, a value smaller than the electrostatic capacitance of a switch snubber capacitor, which requires a relatively large electrostatic capacitance to suppress surge voltage. The same applies to the cases described below in the fourth, sixth, and eighth examples.

[0110] The switching snubber capacitor is, for example, disposed in the path of the positive line PL13 and the negative line NL13 between the smoothing circuit 20 (smoothing capacitor Cdc) and the noise suppression capacitor C2.

[0111] Therefore, in this example, in addition to the noise suppression capacitor C1, a noise suppression capacitor C2 is also provided.

[0112] Therefore, by bypassing the path containing the noise suppression capacitor C2, which has low impedance characteristics relative to high frequencies, high-frequency noise components in the path between the inverter circuit 30 and the smoothing capacitor Cdc can be fed back to the inverter circuit 30. Thus, high-frequency noise components in the path between the inverter circuit 30 and the smoothing capacitor Cdc can be suppressed, thereby suppressing high-frequency noise components induced in the path between the rectifier circuit 10 and the smoothing capacitor Cdc. Therefore, compared to the first example described above, the addition of the noise suppression capacitor C1 further suppresses radiated noise.

[0113] [Fourth example of an electric power conversion device]

[0114] Next, refer to Figure 4 The fourth example of the power conversion device 1 of this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example and the like, and sometimes the descriptions related to the same or corresponding content as the first example and the like will be simplified or omitted.

[0115] Figure 4 This is a circuit diagram showing a fourth example of the power conversion device 1 according to this embodiment.

[0116] like Figure 4 As shown, the power conversion device 1 differs from the second example above in that it adds a noise suppression capacitor C2.

[0117] Similar to the third example above, the noise suppression capacitor C2 is positioned in the path connecting the positive line PL and the negative line NL between the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30. Specifically, the noise suppression capacitor C2 is positioned in the path connecting the positive line PL13 and the negative line NL23 between the smoothing capacitor Cdc and the inverter circuit 30.

[0118] The switching snubber capacitor can be, for example, configured in the path of the positive line PL13 and the negative line NL23 connecting the smoothing circuit 20 (smoothing capacitor Cdc) and the noise suppression capacitor C2.

[0119] Thus, in this example, similar to the third example above, a noise suppression capacitor C2 is also provided in addition to the noise suppression capacitor C1.

[0120] Therefore, compared to the second example above, the addition of the noise suppression capacitor C1 can further suppress radiated noise.

[0121] [The Fifth Example of an Electricity Conversion Device]

[0122] Next, refer to Figure 5 The fifth example of the power conversion device 1 according to this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example and so on, and sometimes the descriptions related to the same or corresponding content as the first example and so on will be simplified or omitted.

[0123] Figure 5 This is a circuit diagram showing a fifth example of the power conversion device 1 according to this embodiment.

[0124] In this example, the circuit configuration other than the rectifier circuit 10, the inverter circuit 30, and the noise suppression capacitor C1 is the same as in the first and third examples described above. Therefore, in Figure 5 The components other than the rectifier circuit 10, inverter circuit 30, and noise suppression capacitor C1 are omitted.

[0125] like Figure 5 As shown, unlike the first and third examples above, the noise suppression capacitor C1 is disposed inside the PIM400 in the path of the positive line PL and the negative line NL connecting the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc).

[0126] Specifically, the noise suppression capacitor C1 is positioned in the path of the negative line NL11, between the branch point connecting the positive line PL11 and the rectifier circuit 10 and the negative line NL12. Thus, similar to the first and third examples described above, the radiated noise of the power conversion device 1 can be suppressed.

[0127] Thus, in this example, the noise suppression capacitor C1 is located inside the PIM400.

[0128] Therefore, it is no longer necessary to connect the noise suppression capacitor C1 externally to the PIM400 via wiring patterns, busbars, etc. on the main substrate. As a result, the manufacturing efficiency of the power conversion device 1 can be improved, and the power conversion device 1 can be miniaturized.

[0129] [Sixth example of an electric power conversion device]

[0130] Next, refer to Figure 6 The sixth example of the power conversion device 1 of this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example, etc., and sometimes the descriptions related to the same or corresponding content as the first example, etc., will be simplified or omitted.

[0131] Figure 6 This is a circuit diagram showing a sixth example of the power conversion device 1 according to this embodiment.

[0132] In this example, the circuit configuration other than the rectifier circuit 10, the inverter circuit 30, and the noise suppression capacitors C1 and C2 is the same as in the third example described above. Therefore, further... Figure 6 The components other than the rectifier circuit 10, inverter circuit 30, and noise suppression capacitors C1 and C2 are omitted.

[0133] like Figure 6 As shown, unlike the third example above, the noise suppression capacitor C1 is disposed inside the PIM400 in the path connecting the positive line PL and the negative line NL between the rectifier circuit 10 and the smoothing circuit 20 (smoothing capacitor Cdc). Similarly, unlike the third example above, the noise suppression capacitor C2 is disposed inside the PIM400 in the path connecting the positive line PL and the negative line NL between the smoothing circuit 20 (smoothing capacitor Cdc) and the inverter circuit 30.

[0134] Specifically, similar to the fifth example above, the noise suppression capacitor C1 is positioned in the path of the negative line NL11 between the branch point connecting the positive line PL11 and the rectifier circuit 10 and the negative line NL12. Thus, similar to the first and third examples above, the radiated noise of the power conversion device 1 can be suppressed.

[0135] Furthermore, the noise suppression capacitor C2 is positioned in the path of the negative line NL11, between the branch point connecting the positive line PL14 and the inverter circuit 30 and the negative line NL12. Thus, similar to the third example described above, the addition of the noise suppression capacitor C1 further suppresses the radiated noise of the power conversion device 1.

[0136] Thus, in this example, noise suppression capacitors C1 and C2 are located inside the PIM400.

[0137] Therefore, it is no longer necessary to connect noise suppression capacitors C1 and C2 externally to the PIM400 via wiring patterns and busbars on the main substrate. As a result, the manufacturing efficiency of the power conversion device 1 can be improved, and the power conversion device 1 can be miniaturized.

[0138] [Seventh Example of an Electricity Conversion Device]

[0139] Next, refer to Figure 7 The seventh example of the power conversion device 1 of this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example and so on, and sometimes the descriptions related to the same or corresponding content as the first example and so on will be simplified or omitted.

[0140] Figure 7 This is a circuit diagram showing a seventh example of the power conversion device 1 according to this embodiment.

[0141] In this example, similar to the fifth and sixth examples above, the rectifier circuit 10, inverter circuit 30, and noise suppression capacitor C1 are built into the PIM400. The external circuitry of the PIM400, except for the noise suppression capacitor C1, can be the same as in the second and fourth examples above. Therefore, in Figure 7 The components other than the rectifier circuit 10, inverter circuit 30, and noise suppression capacitor C1 are omitted.

[0142] like Figure 7 As shown, unlike the first and third examples above, the PIM400 replaces the negative terminal N and includes a negative output terminal N0 and a negative input terminal N1.

[0143] The negative output terminal N0, except that it is provided in PIM400 in place of diode module 100, has the same function as in the second and fourth examples described above. Similar to the second and fourth examples described above, the negative output terminal N0 is connected to the negative terminal Nc of capacitor substrate 200 via negative line NL22 outside PIM400 (e.g., on the main substrate).

[0144] The negative input terminal N1, except that it is provided in PIM400 in place of inverter module 300, has the same function as in the second and fourth examples described above. The negative input terminal N1 is connected to the negative terminal Nc of capacitor substrate 200 via negative line NL23 outside PIM400 (e.g., on the main substrate).

[0145] Similar to the fifth and sixth examples above, the noise suppression capacitor C1 is located inside the PIM400. Specifically, the noise suppression capacitor C1 is located in the path connecting the positive line PL11 and the negative line NL21.

[0146] In the first and third examples described above, the negative terminal N is separated into a negative output terminal N0 and a negative input terminal N1. However, similar to the second and fourth examples, the negative input terminal and negative output terminal of the capacitor substrate 200 are shared at the negative terminal Nc. In other words, in this example, as in the second and fourth examples, the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc is shared with the negative line NL between the inverter circuit 30 and the smoothing capacitor Cdc at the negative terminal Nc. Therefore, the high-frequency noise component at the output of the rectifier circuit 10 becomes relatively large, potentially leading to a relatively increased radiated noise due to components above 30MHz in the high-frequency noise flowing towards the system side.

[0147] In contrast, in this example, the noise suppression capacitor C1 is disposed inside the PIM400. Therefore, similar to the second and fourth examples described above, radiated noise can be suppressed. Furthermore, similar to the fifth and sixth examples described above, the manufacturing efficiency of the power conversion device 1 can be improved, and the power conversion device 1 can be miniaturized.

[0148] In this way, the noise suppression capacitor C1 can also be installed inside the PIM400, where the negative output terminal N0 and the negative input terminal N1 are respectively located.

[0149] [Eighth example of an electric power conversion device]

[0150] Next, refer to Figure 8 The eighth example of the power conversion device 1 according to this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example and so on, and sometimes the descriptions related to the same or corresponding content as the first example and so on will be simplified or omitted.

[0151] Figure 8 This is a circuit diagram showing an eighth example of the power conversion device 1 according to this embodiment.

[0152] In this example, the rectifier circuit 10, the inverter circuit 30, and the noise suppression capacitors C1 and C2 are built into the PIM400. The external circuit configuration of the PIM400, except for the noise suppression capacitors C1 and C2, is the same as in the fourth example described above. Therefore, in Figure 8 The components other than the rectifier circuit 10, inverter circuit 30, and noise suppression capacitors C1 and C2 are omitted.

[0153] like Figure 8 As shown, similar to the seventh example above, the PIM400 includes a negative output terminal N0 and a negative input terminal N1.

[0154] Similar to the sixth example above, noise suppression capacitors C1 and C2 are located inside the PIM400.

[0155] Specifically, the noise suppression capacitor C1 is located in the path connecting the positive line PL11 and the negative line NL21.

[0156] In addition, the noise suppression capacitor C2 is located in the path connecting the positive line PL14 and the negative line NL24.

[0157] In this example, similar to the seventh example above, the negative terminal Nc of both the rectifier circuit 10 and the smoothing capacitor Cdc and the inverter circuit 30 and the smoothing capacitor Cdc is shared. Therefore, the high-frequency noise component at the output of the rectifier circuit 10 becomes relatively large, potentially increasing the radiated noise due to components above 30MHz in the high-frequency noise flowing towards the system side.

[0158] In contrast, in this example, noise suppression capacitors C1 and C2 are disposed inside the PIM400. Therefore, similar to the fourth example above, radiated noise can be further suppressed. In addition, similar to the sixth example above, the manufacturing efficiency of the power conversion device 1 can be improved, thereby enabling the miniaturization of the power conversion device 1.

[0159] In this way, noise suppression capacitors C1 and C2 can be installed inside the PIM400, which has negative output terminal N0 and negative input terminal N1 respectively.

[0160] [Ninth example of an electric power conversion device]

[0161] Next, refer to Figure 9 The ninth example of the power conversion device 1 according to this embodiment will be described. Hereinafter, the description will focus on the parts that are different from the first example and so on, and sometimes the descriptions related to the same or corresponding content as the first example and so on will be simplified or omitted.

[0162] Figure 9 This is a circuit diagram showing the ninth example of the power conversion device 1 according to this embodiment.

[0163] In this example, the rectifier circuit 10 and the noise suppression capacitor C1 are built into the diode module 100. The external circuitry of the diode module 100, except for the noise suppression capacitor C1, can be the same as in the second and fourth examples described above. Therefore, in Figure 9In this version, the components other than the rectifier circuit 10 and the noise suppression capacitor C1 are omitted.

[0164] like Figure 9 As shown, the noise suppression capacitor C1 is disposed inside the diode module 100 in the path connecting the positive line PL11 and the negative line NL21. Thus, similar to the cases in the second and fourth examples described above, the radiated noise of the power conversion device 1 can be suppressed.

[0165] Thus, in this example, the noise suppression capacitor C1 is disposed inside the diode module 100.

[0166] Therefore, it is no longer necessary to connect the noise suppression capacitor C1 externally to the diode module 100 via wiring patterns, busbars, etc. on the main substrate. As a result, the manufacturing efficiency of the power conversion device 1 can be improved, and the power conversion device 1 can be miniaturized.

[0167] Other examples of power conversion devices

[0168] Next, other examples of the power conversion device 1 of this embodiment will be described.

[0169] Appropriate modifications or alterations can be made to the power conversion device 1 in the first to ninth examples mentioned above.

[0170] For example, in the fourth and ninth examples described above, the noise suppression capacitor C2 can be configured inside the inverter module 300. In this case, the noise suppression capacitor C2 can be located in the path connecting the positive line PL14 and the negative line NL24.

[0171] Therefore, it is no longer necessary to connect the noise suppression capacitor C2 externally to the inverter module 300 via wiring patterns, busbars, etc. on the main substrate. As a result, the manufacturing efficiency of the power conversion device 1 can be improved, and the power conversion device 1 can be miniaturized.

[0172] Furthermore, for example, in the first to ninth examples described above, alternative paths to the path between the inverter circuit 30 and the smoothing capacitor Cdc, or other paths with relatively high high-frequency noise components besides the path between the inverter circuit 30 and the smoothing capacitor Cdc, can also be approximated to the path between the rectifier circuit 10 and the smoothing capacitor Cdc. For example, the AC output paths of the inverter circuit 30, i.e., the output lines of the U-phase, V-phase, and W-phase, can be approximated to the path between the rectifier circuit 10 and the smoothing capacitor Cdc.

[0173] Therefore, even if high-frequency noise components are induced from other paths in the path between the rectifier circuit 10 and the smoothing capacitor Cdc, the power conversion device 1 can suppress radiated noise under the action of the noise suppression capacitor C1.

[0174] Additionally, for example, in the first to ninth examples described above, the negative line NL between the rectifier circuit 10 and the smoothing capacitor Cdc is partially shared with the negative line NL between the inverter circuit 30 and the smoothing capacitor Cdc, but it is also possible for them to be shared entirely.

[0175] Alternatively, for example, in the first to ninth examples described above, at least a portion of the positive line PL can be shared between the path between the rectifier circuit 10 and the smoothing capacitor Cdc and the path between the inverter circuit 30 and the smoothing capacitor Cdc, instead of the negative line NL. In this case, the relay for preventing inrush current and the DC reactor of the smoothing circuit 20 can be configured on the negative line NL.

[0176] [effect]

[0177] Next, refer to Figure 10 The function of the power conversion device 1 in this embodiment will be explained.

[0178] Figure 10 This is a graph showing the spectrum of radiated noise of the power conversion device of the comparative example and the power conversion device 1 of this embodiment. Specifically, it shows the spectrum of the radiated electric field intensity of the power conversion device of the first comparative example, the power conversion device of the second comparative example, the power conversion device 1 of the third example, and the power conversion device 1 of the fourth example.

[0179] The power conversion device of the first comparative example has the same configuration as the power conversion device 1 of the third example, except that it does not have noise suppression capacitors C1 and C2. Furthermore, the power conversion device of the second comparative example has the same configuration as the power conversion device 1 of the fourth example, except that it does not have noise suppression capacitors C1 and C2.

[0180] like Figure 10 As shown, under the action of noise suppression capacitors C1 and C2, the radiated electric field intensity in the high-frequency region above 30MHz of the power conversion device 1 in the third example is suppressed to a relatively small value compared to the power conversion device of the first comparative example.

[0181] Similarly, under the action of noise suppression capacitors C1 and C2, the radiated electric field intensity in the high-frequency region above 30MHz of the power conversion device 1 in the fourth example is suppressed to a relatively small value compared to the power conversion device of the second comparative example.

[0182] Thus, in this embodiment, the noise suppression capacitor C1 is located in the path of the positive line PL and the negative line NL connecting the rectifier circuit 10 and the smoothing capacitor Cdc.

[0183] Therefore, the radiated noise of the power conversion device 1 can be suppressed.

[0184] In addition, in this embodiment, the noise suppression capacitor C2 can be located in the path of the positive line PL and the negative line NL connecting the smoothing capacitor Cdc and the inverter circuit 30.

[0185] Therefore, with the addition of the noise suppression capacitor C1, the radiated noise of the power conversion device 1 can be further suppressed.

[0186] The embodiments have been described in detail above, but the present invention is not limited to this specific embodiment. Various modifications and alterations can be made within the scope of the spirit of the claims.

[0187] Explanation of reference numerals in the attached figures

[0188] 1. Power conversion device

[0189] 10 Rectifier Circuit

[0190] 20 Smoothing Circuit

[0191] 30. Inverter Circuit (Power Conversion Circuit)

[0192] 100 Diode Module

[0193] 200 Capacitor Substrate

[0194] 300 inverter module

[0195] 400 PIM

[0196] C1 Noise suppression capacitor (first line capacitor)

[0197] C2 Noise suppression capacitor (second line-to-line capacitor)

[0198] Cdc smoothing capacitor

[0199] Diodes D1 to D6

[0200] N negative extreme

[0201] N0 negative output terminal

[0202] N1 Negative Input Terminal

[0203] Nc negative extreme

[0204] NL, NL11~NL13, NL21~NL24 Negative lines

[0205] P0 positive output terminal

[0206] P1 Positive Input Terminal

[0207] Pc0 positive input terminal

[0208] Pc1 positive output terminal

[0209] PL, PL11~PL14 Positive lines

[0210] R, S, T AC input terminals

[0211] S1~S6 Semiconductor Components

[0212] U, V, W AC output terminals

Claims

1. A power conversion system comprising a main substrate and a power conversion device, the power conversion device includes: a PIM that is a power integrated module including a rectification circuit, a power conversion circuit, a first line-to-line capacitor, and a second line-to-line capacitor; and a capacitor substrate that is a substrate different from the main substrate and includes a smoothing capacitor and a negative terminal, the rectification circuit is configured to convert alternating current inputted from the outside into direct current, the smoothing capacitor is provided in a path connecting a positive line and a negative line of the direct current outputted from the rectification circuit, the power conversion circuit is configured to be connected to the positive line and the negative line in parallel with the smoothing capacitor, and to convert the direct current smoothed by the smoothing capacitor into prescribed alternating current by switching operation of a semiconductor element and output the same, the first line-to-line capacitor is provided in a path of the positive line and the negative line connecting between the rectification circuit and the smoothing capacitor, the second line-to-line capacitor is provided in a path of the positive line and the negative line connecting between the smoothing capacitor and the power conversion circuit, the PIM includes a negative output terminal that leads the negative line from an output terminal of the negative side of the rectification circuit to the outside of the PIM, and a negative input terminal that leads the negative line from an input terminal of the negative side of the power conversion circuit to the outside of the PIM, the negative line includes a first negative line, a second negative line, a third negative line, and a fourth negative line, the first negative line is configured to connect between the output terminal of the rectification circuit and the negative output terminal of the PIM inside the PIM, the second negative line is configured to connect between the negative output terminal of the PIM and the negative terminal of the capacitor substrate on the main substrate outside the PIM, the third negative line is configured to connect between the negative input terminal of the PIM and the negative terminal of the capacitor substrate on the main substrate outside the PIM, the fourth negative line is configured to connect between the input terminal of the power conversion circuit and the negative input terminal of the PIM inside the PIM.

2. The power conversion system according to claim 1, wherein a voltage between the positive line and the negative line at the output terminal of the rectification circuit is equal to or higher than a voltage between the positive line and the negative line at the input terminal of the power conversion circuit.

3. The power conversion system according to claim 1, wherein at least a part of the negative line between the rectification circuit and the smoothing capacitor is shared with the negative line between the power conversion circuit and the smoothing capacitor, or at least a part of the positive line between the rectification circuit and the smoothing capacitor is shared with the positive line between the power conversion circuit and the smoothing capacitor.

4. The power conversion system according to any one of claims 1 to 3, wherein the first interline capacitor has an electrostatic capacitance larger than a junction capacitance of a diode included in the rectification circuit.

5. The power conversion system according to any one of claims 1 to 3, wherein the first interline capacitor is a multilayer ceramic capacitor.

6. The power conversion system according to any one of claims 1 to 3, wherein a plurality of the first interline capacitors are provided, the plurality of the first interline capacitors are connected in series or in parallel between the positive electrode line and the negative electrode line.

7. The power conversion system according to any one of claims 1 to 3, wherein the second interline capacitor has an electrostatic capacitance larger than an electrostatic capacitance between main electrodes at the time of application of a direct current voltage to the semiconductor element.

8. The power conversion system according to claim 7, wherein the second interline capacitor is a multilayer ceramic capacitor.

9. The power conversion system according to claim 7, wherein a plurality of the second interline capacitors are provided, the plurality of the second interline capacitors are connected in series or in parallel between the positive electrode line and the negative electrode line.

Images