JP2019013120A - Power conversion device - Google Patents

Abstract

To provide a power conversion device capable of reducing an influence of noise even when bus bars are arranged close to each other.SOLUTION: A power conversion device comprises: first and second semiconductor elements Q1 and Q2 that perform switching operation; and a laminated bus bar SB that has such a structure that a first bus bar BP at a high power supply side electrically connected with the first semiconductor element Q1 and a second bus bar BN at a low power supply side electrically connected with the second semiconductor element Q2 are laminated via an insulator K. By providing bent parts 93a and 93b on at least one of the first bus bar and the second bus bar, the laminated bus bar SB has a first portion 90 whose distance between the first bus bar and the second bus bar is a first distance a1 and a second portion 92 whose distance between the bus bars is a second distance a2 longer than the first distance.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power conversion device that performs power conversion between DC power and AC power, and more particularly to a power conversion device that can be suitably applied to a hybrid vehicle and an electric vehicle.

  A power converter is a device that converts power between DC power and AC power. The power converter supplies, for example, a DC power supply voltage obtained by boosting or stepping down the battery voltage to a switching circuit via a bus bar that is a plate-like conductor member (metal member), and by switching operation of the switching circuit Convert to AC voltage and supply the AC voltage to the load.

  Since the power conversion device inputs and outputs relatively large power, a plurality of flat bus bars made of a metal material are arranged as electrical wiring. In order to reduce the size of the power conversion device, the bus bars are arranged as close as possible (for example, Patent Document 1).

JP 2007-236044 A

  In the power converter of Patent Document 1, the P bus bar 1 and the N bus bar 2 are arranged close to each other in parallel. With the recent increase in switching speed, the high frequency resistance of the bus bar that forms a current path from a semiconductor element such as an IGBT that is a switching source increases, and leakage current flows through the frame of the bus bar and current noise is likely to be emitted. As an adverse effect, noise may increase and affect other electronic devices. However, if the bus bars are separated and juxtaposed, the size of the power converter increases. Moreover, the resistance of the bus bar is increased due to the increase in speed, and the induction noise resistance due to the stray capacitance may deteriorate.

  An object of this invention is to provide the power converter device which can reduce the influence of a noise even if it arrange | positions a bus-bar close.

  In the following, in order to easily understand the outline of the present invention, embodiments according to the present invention will be exemplified.

  In the first aspect of the power conversion device of the present invention, the first and second semiconductor elements that perform the switching operation, and the high power source that is a plate-like conductor member that is electrically connected to the first semiconductor elements. The first bus bar on the side and the second bus bar on the low power supply side which is a plate-like conductor member electrically connected to the second semiconductor element are stacked via an insulator. A laminated bus bar having a bent portion on at least one of the first bus bar and the second bus bar, whereby the laminated bus bar is provided between the first bus bar and the second bus bar. A first portion in which the distance between the bus bars is a first distance, and a second portion in which the distance between the bus bars is a second distance longer than the first distance.

  Moreover, in the 2nd aspect subordinate to a 1st aspect, the said bending part is provided only in any one of the said 1st bus bar and the said 2nd bus bar.

  Moreover, in the 3rd aspect subordinate to a 1st aspect, the said bending part is provided in both the said 1st bus bar and the said 2nd bus bar.

  Further, in a fourth aspect subordinate to any one of the first to third aspects, the stacked bus bar is configured so that the gap between only the fast areas of the low-speed and high-speed areas of the semiconductor element is the interval. Is getting wider.

  According to the first aspect of the power conversion device of the present invention, the distance between the bus bars in the second portion of the laminated bus bar is longer than the distance between the bus bars in the first portion (in other words, the interval between the bus bars is large). Therefore, the capacitance value of the stray capacitance of the second portion is reduced, and the entire laminated bus bar is uniformly formed of the first portion (in other words, in the case of the conventional configuration), the stray capacitance is passed through the stray capacitance. Leakage current is reduced, and electrostatic induction noise can be reduced. Also, assuming a resonant circuit via a laminated bus bar, the resonant circuit (for example, LC resonant circuit) corresponding to the entire laminated bus bar is the resonant circuit (first resonant circuit) corresponding to the first portion of the laminated bus bar. And a resonance circuit (second resonance circuit) corresponding to the second portion, and thus, for example, the distance between the bus bars of the second portion, and the laminated bus bar in the second portion. By appropriately adjusting the length in the extending direction, etc., it becomes possible to adjust the characteristics of the entire resonance circuit. For example, the value of the resonance frequency is shifted (moved) to a frequency band where radiation noise is unlikely to occur, Alternatively, the Q value (resonance sharpness index) of the entire resonance circuit can be suppressed by combining the Q characteristics of the two resonance circuits, or the resonance peak value can be suppressed. Uninari, therefore, noise can be further suppressed (reduced), and it is possible to provide a power conversion device using the laminated busbar.

  Moreover, according to the 2nd aspect subordinated to a 1st aspect, the bending part which can suppress more noise (reduction) can be provided only in any one of a 1st bus bar and a 2nd bus bar.

  Moreover, in the 3rd aspect subordinate to a 1st aspect, the bending part which can suppress more noise (reduction) can be provided in both a 1st bus bar and a 2nd bus bar.

  Further, in the fourth aspect subordinate to any one of the first to third aspects, the surge on the high-speed switching region side is increased by widening the interval on the high-speed switching region side where noise is easily generated due to fast switching. You can prevent it from getting worse.

1A is a perspective view illustrating an appearance of an example of a power converter, FIG. 1B is a diagram illustrating an aspect of a stacked bus bar drawn from a power supply terminal, and FIG. 1C is a + Z-axis direction. It is a layout figure which shows the example of arrangement | positioning of the semiconductor element which is a component of two inverter circuits, a voltage control unit, and each circuit at the time of seeing through a circuit board from the side. 2A is a circuit diagram showing an example of the overall circuit configuration of the power conversion device of FIG. 1, FIG. 2B is a partial perspective view of a laminated bus bar not including a portion according to the present invention, and FIG. C) is an equivalent circuit diagram of the laminated bus bar shown in FIG. 3A is a perspective view of the main part of the laminated bus bar according to the present invention employed in the power conversion device of FIG. 1, and FIG. 3B is a configuration of the laminated bus bar shown in FIG. FIG. 3C is a diagram showing the measurement results of the frequency characteristics of the high-frequency impedance when the stacked bus bar of FIG. 3A is used and when it is not used. 4 (A) and 4 (B) are diagrams showing structures and equivalent circuits in the first and second modified examples when the bent portion is provided in the laminated bus bar, and FIGS. 4 (C) to 4 (H) are diagrams. It is a figure which shows the structure in the 3rd-8th modification which respectively changes the position which forms a bending part corresponding to the layout of the circuit mounted in a circuit board.

  The best mode described below is used to easily understand the present invention. Accordingly, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

(First embodiment)
First, reference is made to FIG. FIG. 1A is a perspective view showing an external appearance of an IPM (intelligent power module) for a hybrid electric vehicle as an example of a power converter. Hereinafter, the power converter 10 is described as IPM10.

  The IPM 10 can be applied to a two-motor hybrid system, and includes a first inverter (reference numeral 22 in FIG. 2 (A)) that controls a generator for taking out optimum electric power from the engine, And a second inverter (reference numeral 24 in FIG. 2) for controlling the motor (described later). The IPM 10 includes a metal cooling member 12, a power module case 14, and a circuit board 16 disposed on the upper side (+ Z axis side) of the power module case 14.

  The power module case 14 accommodates (accommodates) a stacked bus bar in which semiconductor elements that perform switching operations and P bus bars (positive bus bars) and N bus bars (negative bus bars) as power supply wirings are stacked. (Described later). The P bus bar (positive side bus bar) can be referred to as a first bus bar on the high power supply side which is a plate-like conductor member, and the N bus bar (negative side bus bar) is a low plate type conductor member. It can be said to be a second bus bar on the power supply side.

  Further, the power module case 14 has a rectangular parallelepiped shape (the upper surface is not provided), and AC signals (three phases) of the U, V, and W phases for the generator described above are provided on the side surface in the longitudinal direction (X-axis direction). AC signal output terminals U1, V1, W1 for outputting AC signals), and AC signal output terminals U2, V2, for outputting AC signals (three-phase AC signals) of the U, V, and W phases for the motor described above. W2 is provided. On one of the side surfaces facing each other in the short direction (Y-axis direction) of the power module case 14, a positive power supply terminal VP1 and an N bus bar (negative electrode side) that are electrically connected to the P bus bar (positive bus bar) described above. The negative power supply terminal VN1 electrically connected to the bus bar) is provided, and the positive electrode power supply terminal VP2 and the N bus bar (negative electrode) electrically connected to the P bus bar (positive bus bar) are similarly provided on the other side surface. A negative power supply terminal VN2 electrically connected to the side bus bar) is provided.

  In addition, the circuit board 16 located at the top of FIG. 1A is housed (contained) in the power module case 14, in other words, the semiconductor element provided inside the power module case 14. A switching control circuit for controlling switching is provided. For example, when the semiconductor element is an IGBT (insulated gate bipolar transistor), the circuit board 16 is provided with a gate driver (GD) circuit for driving the gate of the IGBT. In this case, the circuit board is a GD board. It can be said.

  Next, reference is made to FIG. FIG. 1B is a diagram illustrating one mode of a stacked bus bar drawn from a power supply terminal. Note that FIG. 1B is a diagram corresponding to a region S surrounded by a broken line in FIG. As shown in the drawing, each of the P bus bar (positive bus bar) BP and the N bus bar (negative bus bar) BN, which are components of the laminated bus bar SB, is connected to the power module from the positive power supply terminal VP1 and the negative power supply terminal VN1. It is pulled out toward the inside of the case 14, bent in the + Y-axis direction, and then led out in the + X-axis direction. The X-axis direction can be referred to as the extending direction of the stacked bus bar SB.

  Between the P bus bar BP and the N bus bar BN, an electrical insulator (hereinafter simply referred to as an insulator) K made of resin or the like is interposed, and each bus bar BP, BN is connected to the insulator K. They extend away from each other in parallel by a distance corresponding to the thickness (distance between bus bars or insulation distance). Specifically, the distance is set to a1 in the first portion 90 of FIG. 3B (this point will be described later).

  Further, in FIG. 1B, the P bus bar BP and the N bus bar BN are stacked in the Y-axis direction, but may be stacked in the Z-axis direction. In addition, “laminated” means that, for example, the bus bars are arranged in a three-dimensional manner facing each other, and the planar bus bars overlap in a plan view when viewed from a direction orthogonal to the extending direction of the bus bars. (Including at least some overlap).

  FIG. 1C is a layout diagram illustrating an arrangement example of two inverter circuits, a voltage control unit, and semiconductor elements that are components of each circuit when the circuit board is seen through from the + Z-axis direction side. . In FIG. 1C, the first inverter circuit 22 is described as “GEN side inverter”, which means that it is a generator side inverter, and the second inverter circuit 24 is Although described as “TRC side inverter”, this means an inverter on the traction controller side that controls the motor (described later). A voltage control unit (described as VCU in FIG. 1C) 20 is disposed at the center of the bottom surface (for example, the mounting surface) of the power module case 16 that is rectangular in plan view, and the stacked bus bar SB extends. The first direction (X-axis direction) of the voltage control unit (VCU) 20 in a plan view as viewed from a second direction (Z-axis direction) orthogonal to the first direction (X-axis direction) that is present The first inverter 22 and the second inverter 24 are arranged on both sides in FIG. 4B, and a symmetrical and balanced layout is adopted. The advantages of adopting such a layout will be described later.

  The voltage control unit (VCU) 20 supplies a boosted voltage obtained by boosting a DC voltage or a stepped-down voltage obtained by stepping down a DC bus bar (positive electrode) to each of the first and second inverters 22 and 24. The side bus bar) has a function of supplying via the BP, and the voltage control unit (VCU) 20 includes the first and second inverters 22 and 24 as shown in FIG. Specifically, it is housed (contained) inside the power module case 14 adjacent to them.

  The first inverter circuit 22 includes semiconductor elements Q1 to Q6, the second inverter 24 includes semiconductor elements Q7 to Q12, and the voltage control unit (VCU) 20 includes semiconductor elements Qa and Qb. As the semiconductor element, an IGBT (insulated gate bipolar transistor), a GTO (gate turn-off thyristor), or the like can be used. Here, description will be made assuming that an IGBT is used.

  Next, reference is made to FIG. FIG. 2A is a circuit diagram showing an example of the overall circuit configuration of the power conversion apparatus of FIG.

  As shown in FIG. 2A, an IPM (intelligent power module) 10 as a power conversion device includes a first inverter 22, a voltage control unit (VCU) 20, a second inverter 24, and a gate driver. (Gate driver circuit) 40, primary side capacitor 32 connected to battery 30, reactor (coil) 34 used for step-up (step-down), and smoothing capacitor 36 for smoothing the step-up (step-down) power supply voltage And a pair of P bus bars BP and N bus bars BN, positive power supply terminals VP1 and VP2, and negative power supply terminals VN1 and VN2 as power paths (power supply wiring).

  The IPM 10 can be applied to a two-motor hybrid system, and the first inverter 22 is an inverter (in other words, a GEN side) that controls a generator (GEN) 60 for taking out optimum power from the engine 50. The second inverter 24 is an inverter that supplies an AC signal to a traction controller (TRC) 70 that controls the wheel driving motor 80 (in other words, a TRC side inverter).

  The semiconductor elements Q1 and Q2 included in the first inverter 22 constitute a U-phase switching output circuit. A diode D is connected in parallel to each of the semiconductor elements Q1 and Q2. As each semiconductor element Q1, Q2, IGBT can be used as described above.

  Here, in the semiconductor element Q1, a collector is connected to a P bus bar (positive bus bar) BP as a first bus bar on the high power supply side which is a plate-like conductor member (in other words, electrically connected). ), A first semiconductor element that performs a switching operation. Similarly, the collector of the semiconductor element Q2 is connected to an N bus bar (negative bus bar) BN as a second bus bar on the low power source side which is a plate-like conductor member (in other words, electrically connected). ), A second semiconductor element that performs a switching operation. A U-phase AC signal (AC voltage) U10 is output from a common connection point between the emitter of the semiconductor element (IGBT) Q1 and the collector of the semiconductor element (IGBT) Q2, and the AC signal U10 is shown in FIG. Is supplied to the generator (GEN) 60 via the AC signal output terminal U1.

  The above description is about the U-phase switching output circuit including the semiconductor elements Q1 and Q2. However, the description is also applied to the V-phase switching output circuit including the semiconductor elements Q3 and Q4. The present invention is also applied to a W-phase switching output circuit including elements Q5 and Q6.

  Further, the above description is about the first inverter 22, but the same applies to the second inverter 24. Here, the semiconductor elements Q7 and Q8 in the second inverter 24 constitute a U-phase switching output circuit. In the semiconductor element Q7, a collector is connected (in other words, electrically connected) to a P bus bar (positive bus bar) BP as a first bus bar on the high power supply side which is a plate-like conductor member, and switching is performed. It can be said that the third semiconductor element operates. Similarly, the collector of the semiconductor element Q8 is connected to an N bus bar (negative bus bar) BN as a second bus bar on the low power source side which is a plate-like conductor member (in other words, electrically connected). ), A fourth semiconductor element that performs a switching operation. A U-phase AC signal (AC voltage) U20 is output from a common connection point between the emitter of the semiconductor element Q7 as the third semiconductor element and the collector of the semiconductor element Q8 as the fourth semiconductor element. U20 is supplied to the traction controller (TRC) 70 via the AC signal output terminal U2 of FIG. The same description applies to the V-phase switching output circuit and the W-phase switching output circuit in the second inverter 24.

  In the voltage control unit (VCU) 20, a common connection point between the emitter of the semiconductor element (IGBT) Qa and the collector of the semiconductor element (IGBT) Qb is connected to one end of the reactor (coil) 34.

  Each operation (switching operation) of the semiconductor elements Q1 to Q12, Qa, and Qb is individually controlled by a gate control signal output from the gate driver 40. The gate driver 40 functions as a control unit for each of the inverters 22 and 24 and the voltage control unit 20. The gate control signal can also be called a drive signal for driving each semiconductor element (the gate thereof). The gate driver 40 is controlled by an ECU (electronic control unit) 39 as an upper control unit. A signal (for example, a DC signal) generated and output by the generator (GEN) 60 is supplied to the ECU 39. A signal (for example, a DC signal) generated and output by the generator (GEN) 60 is supplied to the ECU 39. Similarly, an output signal from the traction controller (TRC) 70 is also supplied to the ECU 39.

  In FIG. 2A, the smoothing capacitor 36, the reactor (coil) 34, and the primary side capacitor 32 are provided outside the voltage control unit (VCU) 20, but these are appropriately controlled by voltage control. It can be taken into the unit (VCU) 20. In this case, external parts are reduced and the IPM 10 as the power conversion device can be further downsized.

  Next, reference is made to FIG. FIG. 2B is a partial perspective view of a laminated bus bar not including a portion according to the present invention. The laminated bus bar SB as a power path (power supply wiring) includes a P bus bar (positive bus bar) BP as a first bus bar on the high power supply side which is a plate-like conductor member and a low power supply side which is a plate-like conductor member. N bus bar (negative electrode side bus bar) BN as the second bus bar is laminated through an insulator (reference numeral K in FIG. 1A: omitted in FIG. 2B). Each of the P bus bar (positive side bus bar) BP and the N bus bar (negative side bus bar) BN has a bonding wire connection region or a branch arm (not shown) for direct connection to a semiconductor element or the like as appropriate. Provided.

  Next, reference is made to FIG. FIG. 2C is an equivalent circuit diagram of the laminated bus bar shown in FIG. As illustrated, for example, an inductance component L distributed in a P bus bar (positive bus bar) BP and a stray capacitance C between the P bus bar (positive bus bar) BP and the N bus bar (negative bus bar) BN LC circuit (LC series circuit) is configured. This LC circuit may operate as an LC series resonance circuit when a closed loop is formed.

  In other words, the power supply voltage (high potential side power supply voltage, low potential side power supply voltage) of the P bus bar (positive bus bar) BP and the N bus bar (negative electrode bus bar) BN as the power path (power wiring) is, for example, switching High-frequency such as ripple accompanying switching of the circuit (specifically, the switching output circuit for each phase in FIG. 2A) and ripple accompanying voltage boosting or stepping down of the battery 30 using the reactor (coil) 34 Ingredients are mixed. Further, since the P bus bar (positive side bus bar) BP and the N bus bar (negative side bus bar) BN are arranged to face each other, stray capacitance (parasitic capacitance) exists between the bus bars.

  When the frequency of the high frequency component is increased, each bus bar can be regarded as a distributed constant circuit in which an inductance component (L component) and a capacitance component (C component) are continuously distributed along the extending direction of each bus bar. become able to. Further, as is clear from the circuit diagram of FIG. 2A, for example, a smoothing capacitor 36 is connected between each bus bar BP and BN, and each bus bar is connected in an AC manner via the smoothing capacitor 36. Then, there is a possibility that a closed loop via the stray capacitance between the bus bars and the smoothing capacitor 36 may be formed. Therefore, the high frequency component becomes a vibration source, and each bus bar is The possibility that resonance (LC series resonance) occurs through this cannot be denied.

  Therefore, in the embodiment of the present invention, a laminated bus bar having a shape capable of reducing unnecessary radiation (unnecessary radiation reducing shape) is adopted to further improve the level of noise countermeasures. This point will be described with reference to FIGS. 3A is a perspective view of a main part of the laminated bus bar according to the present invention employed in the power conversion device of FIG. 1, and FIG. 3B is a specific example of the laminated bus bar shown in FIG. FIG. 3C is a diagram showing the measurement results of the frequency characteristics of the high-frequency impedance when the stacked bus bar of FIG. 3A is used and when it is not used. Note that an insulator is omitted in FIG. In the present invention, the case of air insulation is not excluded.

  The stacked bus bar SB shown in FIGS. 3A and 3B is bent to at least one of P bus bar (positive side bus bar) BP and N bus bar (negative side bus bar) BN (here, referred to as P bus bar BP). By providing the portions 93a and 93b, a first portion (FIG. 3A) in which the distance between bus bars (insulation distance) between the P bus bar BP and the N bus bar BN is the first distance (a1 in FIG. 3B). 3 (A) surrounded by a broken line 90) and the distance between the bus bars (insulation distance) is a second distance (a2 in FIG. 3B) longer than the first distance a1. A second portion (a portion indicated by reference numeral 92 surrounded by a broken line in FIG. 3A).

  3A and 3B, the P bus bar included in the first portion 90 is expressed as BP (1), and the P bus bar included in the second portion 92 is expressed as BP (2). ing.

  Since the inter-bus bar distance a2 of the second portion 92 of the stacked bus bar SB is longer than the inter-bus bar distance a1 of the first portion 90 (in other words, the interval between the bus bars is large), the floating of the first portion 90 Compared to the capacitance value of the capacitance, the capacitance value of the stray capacitance of the second portion 92 is smaller, and the entire stacked bus bar is uniformly composed of the first portion 90 (in other words, the conventional configuration). As a result, the leakage current through the stray capacitance is reduced. In FIG. 3B, the leakage current J1 in the first portion 90 is large, while the leakage current J2 in the second portion 92 is small. Since the second portion 92 is provided, the leakage current flowing through the stray capacitance is reduced as a whole of the stacked bus bar SB, and thus electrostatic induction noise can be reduced.

  Further, assuming a resonant circuit via the laminated bus bar SB, the resonant circuit corresponding to the entire laminated bus bar SB (the LC resonant circuit as shown in FIG. 2C) is the lower left side of FIG. The first resonance circuit M1 (inductance component is L1 and capacitance component is C1) M1 corresponding to the first portion 90 of the laminated bus bar SB and the second portion 92 corresponding to the second portion 92, as shown in FIG. It can be regarded as a combination with a resonance circuit M2 (inductance component is L2, capacitance component is C2, and capacitance value has a relationship of C1> C2).

  Therefore, for example, the distance a2 between the bus bars of the second portion 92 or the length of the second portion 92 in the extending direction of the stacked bus bars SB (X-axis direction in the examples of FIGS. 3A and 3B). (In other words, the distance from the bent portion 93a to the bent portion 93b) or. By changing the design such that the bent portion is repeatedly provided (in other words, a plurality of second portions 92 are provided), the characteristics of the partial LC circuit can be adjusted as appropriate. It becomes possible to adjust (control) the characteristics of the resonance circuit.

  For example, the value of the resonance frequency is shifted to a frequency band where radiation noise is unlikely to occur, or the Q value (index of resonance sharpness) of the entire resonance circuit is suppressed by combining the Q characteristics of the two resonance circuits, or It becomes possible to suppress the resonance peak value, and therefore, it is possible to provide a power converter (for example, IPM 10) using the laminated bus bar SB that can further suppress (reduce) noise.

  Reference is made to FIG. In FIG. 3C, the horizontal axis represents the frequency (unit: MHz) of the high frequency component mixed in the laminated bus bar, and the vertical axis represents the high frequency impedance (high frequency resistance: unit Ω) in the laminated bus bar SB. A characteristic line 110 indicated by a broken line indicates a frequency characteristic when the distance between the bus bars in the laminated bus bar is uniformly a1 (when the present invention is not applied), and a characteristic line 112 indicated by a solid line is a figure in the laminated bus bar SB. 3 (B) shows frequency characteristics when the first portion 90 and the second portion 92 (one place) are provided (when the present invention is applied).

  The characteristic line 112 when the present invention is applied has lower impedance in the high frequency band than the characteristic line 110 when the present invention is not applied, and the frequency at which the peak occurs is approximately on the high frequency side. It is slightly shifted (shifted), and it can be seen that the high-frequency characteristics of the circuit are adjusted. This is because when the present invention is applied, the characteristics of the entire circuit are determined by the synthesis of two LC circuits (LC resonant circuits) M1 and M2, as shown in FIG. It can be said that the result is a change in the high-frequency characteristics of the entire circuit.

  The present invention is not limited to the example of FIG. For example, in the example of FIG. 3A, the bent portions (stepped portions) 93a and 93b are provided along the X-axis direction that is the extending direction of the laminated bus bar SB, but the bent portions (stepped portions) are not provided. The capacitance value of the stray capacitance between the bus bars can also be changed by providing the stacked bus bars SB along the width direction (Z-axis direction). Such variations can be made as appropriate.

  In the example of FIG. 3A, the bent portions 93a and 93b are bent at 90 degrees (that is, at right angles) with respect to the extending direction of the laminated bus bar SB. However, the shape may be a shape that is inclined and bent at an angle of less than 90 degrees with respect to the extending direction of the laminated bus bar SB. When the inclined bending is adopted, the electric field concentration at the edge of the bent portion (so-called edge effect) can be mitigated as compared with the case of bending at a right angle, which is effective in suppressing noise. It is considered a thing.

  Further, in the above example, a configuration in which a pair of bus bars is stacked is shown, but even in a multilayer stacked bus bar in which more bus bars are stacked, by providing a bent portion in at least one of the bus bars, Similar effects can be obtained.

  As described above, in the embodiment of the present invention, at least one of the bus bars constituting the laminated bus bar is provided with a bent portion. The technical significance of forming the bent portion is, for example, simply avoiding an obstacle. It is not a mechanical significance but a meaning of positively adjusting (controlling) circuit constants.

  In other words, the stacked bus bar SB includes the first portion 90 and the second portion 92, so that the capacitance value of the stray capacitance between the bus bars in the first portion 90 and each bus bar in the second portion 92 are reduced. A difference occurs between the capacitance values of the stray capacitances between them, and in the second portion 92, the capacitance value decreases, the leakage current is reduced, and the induced noise caused by the leakage current is suppressed. An effect is obtained. In addition to the above effect, the resonance frequency of the resonance circuit (first resonance circuit) M1 including each bus bar and stray capacitance corresponding to the first portion 90 as components, and the second portion 92 A difference occurs in each frequency value of the resonance frequency of the resonance circuit (second resonance circuit) M2 including each corresponding bus bar and stray capacitance as components, and the first resonance circuit M1 and the second resonance circuit M2 By combining (synthesized), it is possible to obtain a circuit design effect that the characteristics of the resonant circuit including the entire laminated bus bar SB as a component can be determined (adjusted).

(Second Embodiment)
Next, a modified example (application example) of the present invention will be described with reference to FIGS.
4 (A) and 4 (B) are diagrams showing structures and equivalent circuits in the first and second modified examples when the bent portion is provided in the laminated bus bar, and FIGS. 4 (C) to 4 (H) are diagrams. It is a figure which shows the structure in the 3rd-8th modification which respectively changes the position which forms a bending part corresponding to the layout of the circuit mounted in a circuit board. In FIGS. 4A to 4H, each bus bar is indicated by a thick solid line.

  In the example of FIG. 4A, a bent portion is repeatedly provided in a P bus bar (positive bus bar) BP, and BP (1) and BP (2) are repeatedly provided. As described in the example of FIGS. 3A and 3B, BP (1) is a P bus bar constituting the first portion 90, and BP (2) constitutes the second portion 92. P bus bar. As a result, as shown in the circuit diagram shown in the lower part of FIG. 4A, seven LC circuits (LC resonance circuits) are configured, and the combination of these makes the characteristics of the entire LC circuit (LC resonance circuit). It will be decided. Therefore, finer circuit constants (resonance frequency, etc.) can be adjusted.

In the example of FIG. 4B, the bent portion is provided also in the N bus bar (negative electrode side bus bar) BN in the laminated bus bar SB. In other words, the N bus bar (negative electrode side bus bar) BN also adopts a configuration in which BN (1) and BN (2) are repeated corresponding to each of the first portion 90 and the second portion 92. The bending direction (−Z axis direction) of the bus bar in the N bus bar (negative electrode side bus bar) BN is opposite to the bending direction (+ Z axis direction) of the bus bar in the P bus bar (positive electrode side bus bar) BP, and vice versa. Since the bent portion of the direction is provided corresponding to the bent portion of the P bus bar (positive bus bar) BP,
The distance between BP (2) and BN (2) (distance between bus bars or insulation distance) is twice that in FIG. 4A, and the capacitance value of stray capacitance can be made smaller. is there. Note that the equivalent circuit of the stacked bus bar in FIG. 4B has a configuration in which an LC circuit (LC resonance circuit) M1 and an LC circuit (LC resonance circuit) M3 are repeated. The LC circuit (LC resonance circuit) M3 is an LC circuit (LC resonance circuit) at a location including BP (2) and BN (2) as components.

  Next, reference will be made to FIGS. These configurations are employed with the intention of adjusting the position of the bent portion of the bus bar in correspondence with the layout including the two inverters shown in FIG. 4C to 4H, a portion where the unnecessary radiation reduction shape (unnecessary radiation reduction structure) in the laminated bus bar is adopted (hereinafter referred to as “unnecessary radiation reduction shape portion”) is surrounded by a broken line, and Reference numerals H1 to H7 are attached.

  As described above with reference to FIG. 1C and FIG. 2A, the IPM 10 as the power conversion device includes the first inverter 22 on the generator side (GEN side inverter) 22 and the second inverter on the traction controller side. Inverter (TRC side inverter) 24 has a layout configuration arranged on both sides of the voltage control unit (VCU) 20 (both sides in the extending direction of the stacked bus bar SB). Further, the first and second semiconductor elements (for example, Q1 and Q2) included in the first inverter 22 are more than the third and fourth semiconductor elements (for example, Q7 and Q8) included in the second inverter 24. Are switched by a driving signal having a higher frequency (in other words, the operating frequency of the first inverter 22 is set higher than the operating frequency of the second inverter 24), and the stacked bus bar SB is connected to the first and second It is used as a common power path for the inverters 22 and 24 (this point is apparent from the circuit diagram of FIG. 2A).

  In this case, in the example of FIG. 4C, the bent portions 93a and 93b provided on the P bus bar (positive bus bar) BP are provided in the mounting region of the first inverter (GEN side inverter) 22. In other words, the unnecessary radiation reducing shape portion H <b> 1 is provided in the mounting region of the first inverter 22. By providing in the mounting region of the first inverter where the noise is likely to occur due to the high operating frequency, for example, the capacitance value of the stray capacitance is reduced, and the electrostatic induction noise for the first inverter where the noise is likely to occur is effective. The effect that it reduces automatically is acquired.

  The “mounting area of the first inverter” is a rectangular area surrounded by a broken line and denoted by reference numeral 22 in the example of FIG. As described above, the first inverter 22, the second inverter 24, the voltage control unit (VCU) 20, and the laminated bus bar SB are accommodated in the power module case 14 (see FIG. 1A). . For example, the bottom surface of the power module case 14 is a mounting surface, and a semiconductor element (power chip) is mounted on the mounting surface to constitute each inverter. As shown in FIG. 1C, the mounting area of the first inverter 22 is uniquely determined in a plan view viewed from a direction (+ Z-axis direction) orthogonal to the extending direction of the stacked bus bars. And in the area | region (specifically the part arrange | positioned in the vicinity) corresponding to the mounting area | region of the 1st inverter 22 among laminated bus bars SB, it is bending part 93a, 93b (in other words, unnecessary radiation reduction shape) H1) is provided. The above description can also be applied to the mounting area of the second inverter 24.

  In the example of FIG. 4D, the unnecessary radiation reduction shape H2 shown in FIG. 4A is employed in the portion of the stacked bus bar SB corresponding to the mounting area of the first inverter 22. In the example of FIG. 4E, the unnecessary radiation reduction shape H3 shown in FIG. 4B is employed in the portion of the stacked bus bar SB corresponding to the mounting area of the first inverter 22. In either case, the same effect as the example of FIG. 4C can be obtained.

  On the other hand, in the laminated bus bar SB, when there is a concern about an adverse effect due to an increase in inductance component (L component) due to the formation of the bent portions 93a, 93b, etc. (for example, when the bent portions are repeatedly provided) Avoiding the mounting region of the first inverter 22 having a high frequency, the bent portions 93a and 93b are mounted in the mounting region of the second inverter 24 where the operating frequency is low and noise due to an increase in the inductance component (L component) hardly occurs. Etc. may be provided. This example is shown in FIGS. 4 (F), (G), and (H). In each example of FIGS. 4F, 4G, and 4H, unnecessary radiation reduction shapes H4, H5, and H6 are provided corresponding to the mounting region of the second inverter 24. In these examples, it is possible to take effective measures such as adjusting the resonance frequency of the entire laminated bus bar to make it difficult for resonance to occur while suppressing noise due to an increase in inductance component (L component).

  Next, with reference to FIG. 1C, the advantage of the layout configuration in which the first and second inverters 22 and 24 are provided on both sides of the voltage control unit (VCU) 20 will be described.

  Here, the voltage control unit (VCU) 20 sends a boosted voltage (step-down voltage) obtained by boosting (or stepping down) a DC voltage (for example, the voltage of the battery 30) via a P bus bar (positive bus bar) BP. Function as a kind of power supply.

  In the example of FIG. 1C, when the direction in which the stacked bus bar SB extends (specifically, the X-axis direction) is the first direction, both sides of the voltage control unit (VCU) 20 (first direction) A bilaterally symmetric layout configuration is employed in which the first and second inverters 22 and 24 are arranged on both sides of the first and second inverters. Thus, the lengths of the P bus bar BP and the N bus bar BN connecting the voltage control unit (VCU) 20 and the first and second inverters 22 and 24 (in other words, the length of the power path to each inverter). Is minimized.

  Therefore, since the inductance component (L component) of each bus bar BP, BN is reduced, the L component does not become a dominant element, and therefore, by providing the above-described unnecessary radiation reduction shape, between the bus bars. The preferable effect of reducing the stray capacitance (reducing the C component) is easily realized, and, for example, the first and second inverters 22 and 24 are symmetrically arranged around the voltage control unit (VCU) 20. Arrangement improves the balance of the circuit, suppresses unnecessary reflection and the like, and reduces unnecessary radiation. In other words, adopting the layout configuration as shown in FIG. 1C to minimize the adverse effects due to the L component, while adopting the laminated bus bar having the unnecessary radiation reduction shape, the advantageous effect is obtained. Can be obtained.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various deformation | transformation and application are possible. For example, the present invention can be applied to a power conversion circuit including a direct current chopper, and can also be applied to a power conversion device including a multilayer bus bar. Further, the power conversion device can be used for ships and general industries, in addition to being mounted on an electric vehicle or a so-called hybrid vehicle.

  The present invention is suitable, for example, as a power conversion device mounted on a vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Power converter (IPM), 12 ... Cooling member, 14 ... Power module case, 16 ... Circuit board (GD board | substrate which mounts a gate driver), 20 ... Voltage control unit ( VCU), 22 ... first inverter (generator side inverter), 24 ... second inverter (traction controller side substrate), 30 ... battery, 32 ... primary side capacitor, 34 ... Reactor (coil), 36 ... smoothing capacitor, 40 ... electronic control unit (ECU), 50 ... engine, 60 ... generator (GEN), 70 ... traction controller (TRC), 80 ... -Motor, 90 ... first part of laminated bus bar, 92 ... second part of laminated bus bar, 93a, 93b ... bent part (step part , BP ... P bus bar (positive side bus bar), BN ... N bus bar (negative side bus bar), BP (1) ... P bus bar corresponding to the first part 90, BN (1) ... the part corresponding to the first part 90 of the N bus bar, BP (2) ... the part corresponding to the second part 92 of the P bus bar, BN (2) ... the part of the N bus bar A portion corresponding to the second portion 92, a1... First bus bar distance (first insulation distance), a2... Second bus bar distance (second insulation distance), M1 to M3.・ Partial LC circuit (LC resonance circuit) with laminated bus bar and stray capacitance as components, H1 to H6... Unnecessary radiation mitigation shape (unnecessary radiation reducing structure) in laminated bus bar, Q1 to Q12, Qa, Qb ..Semiconductor elements (IGBT etc.)

Claims (4)

First and second semiconductor elements that perform a switching operation;
A first bus bar on the high power supply side which is a plate-like conductor member electrically connected to the first semiconductor element, and a plate-like conductor member electrically connected to the second semiconductor element A second bus bar on the low power supply side, and a laminated bus bar having a structure in which the second bus bar is laminated via an insulator;
With
The laminated bus bar is provided with a bent portion in at least one of the first bus bar and the second bus bar, so that the distance between the first bus bar and the second bus bar is the first distance between the first bus bar and the second bus bar. A power converter comprising: a first portion that is a distance; and a second portion that is a second distance in which the distance between the bus bars is longer than the first distance.   The power converter according to claim 1, wherein the bent portion is provided in only one of the first bus bar and the second bus bar.   The power converter according to claim 1, wherein the bent portion is provided in both the first bus bar and the second bus bar.   4. The stack bus bar according to claim 1, wherein the gap is wide only in the fast region among the slow region and the fast region where the switching speed of the semiconductor element is low. 5. Power conversion device.

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