JP2022063459A - Conductor unit - Google Patents

Abstract

To provide a conductor unit capable of reducing inductance.SOLUTION: A conductor unit according to an embodiment comprises a first conductor and a second conductor, and a third conductor. The first conductor and the second conductor are at least two conductor bodies having a first polarity of a positive polarity and a negative polarity. The third conductor is arranged between the first conductor and the second conductor. The third conductor is at least one conductor body having a second polarity different from the first polarity. The first conductor is connected with a first terminal provided at both ends of a first capacitor of a plurality of capacitors. The second conductor is connected with a second terminal provided at both ends of a second capacitor of the plurality of capacitors. The third conductor is connected with a third terminal provided at both ends of the first capacitor and connected with a fourth terminal provided at both ends of the second capacitor.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to conductor units.

Conventionally, there is an element module including a power conversion circuit including at least one semiconductor element and a smoothing capacitor (capacitor) connected between the positive electrode and the negative electrode of the power conversion circuit.
However, there is a possibility that the surge voltage associated with the switching operation of the semiconductor element may increase due to the stray inductance between the semiconductor element and the capacitor.

Japanese Unexamined Patent Publication No. 2009-44152

An object to be solved by the present invention is to provide a conductor unit capable of reducing inductance.

The conductor unit of the embodiment includes a first conductor, a second conductor, and a third conductor. The first conductor and the second conductor are at least two conductors having the first polarity among the positive electrode and the negative electrode. The third conductor is arranged between the first conductor and the second conductor. The third conductor is at least one conductor having a second polarity, which is a polarity different from the first polarity. The first conductor is connected to the first terminals at both ends of the first capacitor among the plurality of capacitors. The second conductor is connected to the second terminals at both ends of the second capacitor among the plurality of capacitors. The third conductor is connected to the third terminals at both ends of the first capacitor and is connected to the fourth terminals at both ends of the second capacitor.

The block diagram of the power conversion system including the conductor unit of embodiment. The block diagram of a part of the power conversion system of an embodiment. The block diagram of the conductor unit and the capacitor unit of an embodiment. The figure which shows the example of the current density distribution of each conductor unit of an Example of an Embodiment and a comparative example. FIG. 6 is a configuration diagram of a power conversion system including a conductor unit in a modified example of the embodiment. FIG. 6 is a configuration diagram of a conductor unit and a capacitor unit in a modified example of the embodiment.

Hereinafter, the conductor unit of the embodiment will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a drive system 1 including the conductor unit 10 of the embodiment. FIG. 2 is a block diagram of a part of the power conversion system 4 of the embodiment. FIG. 3 is a configuration diagram of the conductor unit 10 and the capacitor unit 12 of the embodiment.

As shown in FIG. 1, the drive system 1 of the embodiment includes an AC power supply 2, a rotary electric machine (M) 3, and a power conversion system 4.
The AC power source 2 is, for example, a commercial power source or a generator. The AC power supply 2 supplies AC power such as three-phase AC power to the power conversion system 4.
The rotary electric machine 3 is an AC electric machine such as an induction motor and a synchronous motor. The rotary electric machine 3 generates a rotary drive force by AC power supplied from the power conversion system 4 during power running operation. The rotary electric machine 3 may perform regenerative operation. The rotary electric machine 3 generates AC power by the rotational driving force input to the rotary shaft during the regenerative operation.

The power conversion system 4 converts the AC power supplied from the AC power source 2 and supplies the converted AC power to the rotary electric machine 3. The power conversion system 4 may operate to regenerate the power supply. The power conversion system 4 converts the AC power supplied from the rotary electric machine 3 during the power regeneration operation, and supplies the converted AC power to the AC power supply 2.
The power conversion system 4 includes, for example, a conductor unit 10, a first power converter 11, a capacitor unit 12, a second power converter 13, a control unit 14, and a current detector 15.

The conductor unit 10 connects the first power converter 11, the capacitor unit 12, and the second power converter 13. The conductor unit 10 includes a plurality of conductors such as a copper plate. The outer shape of each of the plurality of conductors is, for example, a flat plate. The plurality of conductors are, for example, one P-phase conductor (P) 21 on the positive electrode side, and two first N-phase conductors (N1) 22 and a second N-phase conductor (N2) 23 on the negative electrode side. The area of the main surface, which is the surface with the largest surface area of each conductor 21, 22, 23, is the same. The thickness of the P-phase conductor 21 is twice the thickness of each of the first N-phase conductor 22 and the second N-phase conductor 23.

As shown in FIG. 3, the first N-phase conductor 22 and the second N-phase conductor 23 sandwich the P-phase conductor 21 from both sides in the thickness direction (Z-axis direction). The first N-phase conductor 22 and the second N-phase conductor 23 are connected to the same potential.
The first main surface 21A of the P-phase conductor 21 and the main surface 22A of one of the first N-phase conductors 22 (on the P-phase conductor 21 side) face each other by a predetermined distance in the thickness direction (Z-axis direction), and are thick to each other. It is parallel to the orthogonal direction (X-axis direction and Y-axis direction) in the vertical direction. The second main surface 21B of the P-phase conductor 21 and the main surface 23A of one of the second N-phase conductors 23 (on the P-phase conductor 21 side) face each other by a predetermined distance in the thickness direction (Z-axis direction). It is parallel to each other in the orthogonal direction in the thickness direction (X-axis direction and Y-axis direction).
The X-axis, Y-axis, and Z-axis directions orthogonal to each other in the three-dimensional space are parallel to each axis. For example, the Z-axis direction is parallel to the thickness direction of each conductor 21, 22, 23. The X-axis direction and the Y-axis direction are directions orthogonal to the thickness direction of each conductor 21, 22, 23.

The first power converter 11 includes a forward conversion circuit that converts AC power input from AC power supply 2 into DC power and outputs it to the conductor unit 10. The first power converter 11 includes, for example, at least one switching element. The switching element is a transistor such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Oxide Semi-conductor Field Effect Transistor). The first power converter 11 switches between on (conduction) and off (disconnection) based on a switching command input from the control unit 14 to the switching element.

The first power converter 11 includes, for example, a three-phase U-phase terminal 11U, a V-phase terminal 11V, and a W-phase terminal 11W connected to the AC power supply 2. The first power converter 11 includes a positive electrode terminal 11P connected to the P-phase conductor 21 of the conductor unit 10 and a negative electrode terminal 11N connected to the first N-phase conductor 22 and the second N-phase conductor 23 of the conductor unit 10. ..

As shown in FIGS. 1, 2 and 3, the capacitor unit 12 is a plurality of capacitors connected in parallel between the P-phase conductor 21 of the conductor unit 10 and the first N-phase conductor 22 and the second N-phase conductor 23. It is equipped with a (capacitor). The plurality of capacitors are, for example, three capacitors, that is, a first capacitor (C1) 31, a second capacitor (C2) 32, and a third capacitor (C3) 33. The capacitor unit 12 smoothes the voltage fluctuation generated by the on / off switching operation of each switching element of the first power converter 11 and the second power converter 13.

The first capacitor 31 includes a positive electrode terminal 31P connected to the P-phase conductor 21 of the conductor unit 10 and a negative electrode terminal 31N connected to the first N-phase conductor 22 of the conductor unit 10.
The second capacitor 32 includes a positive electrode terminal 32P connected to the P-phase conductor 21 of the conductor unit 10 and a negative electrode terminal 32N connected to the second N-phase conductor 23 of the conductor unit 10.
The third capacitor 33 includes a positive electrode terminal 33P connected to the P-phase conductor 21 of the conductor unit 10 and a negative electrode terminal 33N connected to the first N-phase conductor 22 and the second N-phase conductor 23 of the conductor unit 10.
Of the plurality of terminals of the capacitor unit 12 connected to the conductor unit 10, the number of terminals connected to the first N-phase conductor 22 (for example, negative electrode terminals 31N and 33N) and the number of terminals connected to the second N-phase conductor 23 are connected. The number of connections of the terminals (for example, the negative electrode terminals 32N and 33N) is the same.

The second power converter 13 includes an inverse conversion circuit that converts DC power input from the conductor unit 10 into AC power and outputs the DC power to the AC power line 41. The second power converter 13 includes, for example, at least one switching element and a rectifying element. The switching element is a transistor such as an IGBT or MOSFET. The rectifying element is a diode connected in parallel with the transistor. The second power converter 13 includes, for example, a bridge circuit formed by a plurality of switching elements and rectifying elements bridge-connected in two phases, A phase and B phase.

The second power converter 13 includes high-side arm and low-side arm A-phase transistors SaH and SaL paired with A phase, and high-side arm and low-side arm B-phase transistors SbH and SbL paired with B phase. The second power converter 13 includes a freewheeling diode connected in the forward direction from the emitter to the collector between the collector and the emitter of each transistor SaH, SaL, SbH, SbL.

The second power converter 13 includes a first positive electrode terminal PT1 connected to the collector of the high side arm A phase transistor SaH and a second positive electrode terminal PT2 connected to the collector of the high side arm B phase transistor SbH. The first positive electrode terminal PT1 and the second positive electrode terminal PT2 are connected to the P-phase conductor 21 of the conductor unit 10.
The second power converter 13 includes a first negative electrode terminal NT1 connected to the emitter of the low-side arm A-phase transistor SaL and a second negative electrode terminal NT2 connected to the emitter of the low-side arm B-phase transistor SbL. The first negative electrode terminal NT1 is connected to the first N-phase conductor 22 of the conductor unit 10. The second negative electrode terminal NT2 is connected to the second N-phase conductor 23 of the conductor unit 10.

The second power converter 13 includes an A-phase terminal AT connected to the emitter of the high-side arm A-phase transistor SaH and the collector of the low-side arm A-phase transistor SaL. The second power converter 13 includes a B-phase terminal BT connected to the emitter of the high-side arm B-phase transistor SbH and the collector of the low-side arm B-phase transistor SbL. The A-phase terminal AT and the B-phase terminal BT are connected to an AC electric line 41 between the rotary electric machine 3 and the rotary electric machine 3.

The second power converter 13 switches on (conducting) and off (disconnecting) the transistor pair of each phase based on the switching command input from the control unit 14 to the gate of each transistor SaH, SaL, SbH, SbL. The second power converter 13 converts the DC power input from the first positive electrode terminal PT1 and the second positive electrode terminal PT2 and the first negative electrode terminal NT1 and the second negative electrode terminal NT2 into single-phase AC power, and after conversion. Single-phase AC power is output from the A-phase terminal AT and the B-phase terminal BT.

The control unit 14 controls the operation of the drive system 1. For example, the control unit 14 is a software function unit that functions by executing a predetermined program by a processor such as a CPU (Central Processing Unit). The software function unit is an ECU (Electronic Control Unit) including a processor such as a CPU, a ROM (Read Only Memory) for storing a program, a RAM (Random Access Memory) for temporarily storing data, and an electronic circuit such as a timer. .. At least a part of the control unit 14 may be an integrated circuit such as an LSI (Large Scale Integration).

The control unit 14 sets the timing of on / off switching drive of each switching element of the first power converter 11 and the second power converter 13, and is a gate for actually driving each switching element on and off. Generate a signal. For example, the control unit 14 controls the feedback based on the signal of the detected value output from the current detector 15 that detects the load current flowing through the AC electric circuit 41, and the second power converter 13 during the power running operation of the rotary electric machine 3. The gate signal is output to the switching element of. The gate signal is, for example, a pulse signal controlled by pulse width modulation (PWM).

Hereinafter, the diversion balance between the capacitor unit 12 and the switching elements of the first power converter 11 and the second power converter 13 will be described.
FIG. 4 is a diagram showing an example of the current density distribution of each conductor unit of the embodiment and the comparative example.
The embodiment shown in FIG. 4 is an example of the current density distributions of the P-phase conductor (P) 21, the first N-phase conductor (N1) 22, and the second N-phase conductor (N2) 23 of the conductor unit 10 of the above-described embodiment. Is. The comparative example shown in FIG. 7 is an example of the current density distribution of each of the two conductors constituting the conductor unit. The two conductors in the comparative example are a P-phase conductor (P) and an N-phase conductor (N). The shapes such as the thickness and surface area of the P-phase conductor (P) and the N-phase conductor (N) are the same.

When a current containing a harmonic component flows through a plate-shaped conductor, the inductance of the conductor decreases as the surface area of the conductor increases.
In the conductor unit of the comparative example including two conductors (P-phase conductor (P) and N-phase conductor (N)), when the surface area of the conductor as a whole is increased without increasing the number of conductors, each conductor is conductive. There is a problem that the shape of the body becomes large. For example, when increasing the area of the main surface of each conductor, there arises a problem that the dimension in the width direction orthogonal to the thickness direction increases.

On the other hand, the conductor of the embodiment in which the number of conductors is increased and three conductors (P phase conductor (P) 21, first N phase conductor (N1) 22 and second N phase conductor (N2) 23) are provided. In the unit 10, the surface area of the conductor as a whole is increased by only a slight dimensional increase in the thickness direction in which the three conductors are arranged.
In the embodiment, the P-phase conductor 21 is sandwiched between the first N-phase conductor 22 and the second N-phase conductor 23 from both sides in the thickness direction (Z-axis direction), whereby both sides of the P-phase conductor (P) 21 in the thickness direction. The two regions where the current is concentrated are divided into the first N-phase conductor (N1) 22 and the second N-phase conductor (N2) 23, respectively, to ensure a uniform diversion balance.

According to the embodiment described above, the conductor unit 10 includes the P-phase conductor 21 arranged between the first N-phase conductor 22 and the second N-phase conductor 23, so that the shape of each conductor becomes large. It is possible to increase the surface area of the conductor as a whole while suppressing the above. As the surface area of the conductor as a whole increases, the inductance between the capacitor unit 12 and the switching elements of the first power converter 11 and the second power converter 13 can be reduced.

The number of connections of terminals connected to the first N-phase conductor 22 (for example, negative electrode terminals 31N, 33N) and the number of connections of terminals connected to the second N-phase conductor 23 (for example, negative electrode terminals 32N, 33N) are the same. By providing a certain capacitor unit 12, a uniform diversion balance can be ensured.
A first N-phase conductor 22 having a main surface 22A facing the first main surface 21A of the P-phase conductor 21 and a second N-phase conductor 23 having a main surface 23A facing the second main surface 21B of the P-phase conductor 21 are provided. As a result, the skin effect and proximity effect can be reduced and the current can flow more uniformly, as compared with, for example, a comparative example having one P-phase conductor (P) and one N-phase conductor (N).
By providing the first N-phase conductor 22 and the second N-phase conductor 23 having the respective main surfaces 22A and 23A having the same surface area as the surface areas of the first main surface 21A and the second main surface 21B of the P-phase conductor 21. It is possible to increase the surface area of the conductor as a whole while suppressing the increase in the shape of each conductor.

Hereinafter, a modified example will be described.
In the above-described embodiment, the capacitor unit 12 includes an odd number of capacitors, but the present invention is not limited to this. The capacitor unit 12 may include an even number of capacitors.
FIG. 5 is a configuration diagram of a power conversion system 4A including the conductor unit 10 in the modified example of the embodiment. FIG. 6 is a configuration diagram of the conductor unit 10 and the capacitor unit 12A in the modified example of the embodiment.

As shown in FIGS. 5 and 6, the capacitor unit 12A of the modified example corresponds to the configuration obtained by omitting the third capacitor 33 from the capacitor unit 12 of the above-described embodiment.
Of the plurality of terminals of the capacitor unit 12A connected to the conductor unit 10, the number of terminals connected to the first N-phase conductor 22 (for example, the negative electrode terminal 31N) and the terminals connected to the second N-phase conductor 23 (for example). For example, the number of connections of the negative electrode terminal 32N) is the same.

In the above-described embodiment, the conductor unit 10 includes one P-phase conductor (P) 21 on the positive electrode side, and two first N-phase conductors (N1) 22 and a second N-phase conductor (N2) 23 on the negative electrode side. However, it is not limited to this. For example, the combination of the polarities of the positive electrode and the negative electrode of the plurality of conductors of the conductor unit 10 may be reversed. For example, the conductor unit 10 is arranged between the first P phase conductor (P1) and the second P phase conductor (P2) on the two positive electrode sides, and the first P phase conductor (P1) and the second P phase conductor (P2). It may be provided with one N-phase conductor (N) on the negative electrode side.

In the above-described embodiment, the conductor unit 10 includes, but is not limited to, three conductors (that is, a P-phase conductor 21, a first N-phase conductor 22 and a second N-phase conductor 23). The conductor unit 10 may include a larger number of conductors, for example, five conductors.

According to at least one embodiment described above, the conductor unit 10 includes a P-phase conductor 21 arranged between the first N-phase conductor 22 and the second N-phase conductor 23, so that the shape of each conductor can be changed. It is possible to increase the surface area of the conductor as a whole while suppressing the increase. As the surface area of the conductor as a whole increases, the inductance between the capacitor unit 12 and the switching elements of the first power converter 11 and the second power converter 13 can be reduced.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Drive system, 2 ... AC power supply, 3 ... Rotating electric machine (M), 4, 4A ... Power conversion system, 10 ... Conductor unit, 11 ... First power converter, 12, 12A ... Capacitor unit, 13 ... Second Power converter, 14 ... Control unit, 21 ... P phase conductor (P), 22 ... 1st N phase conductor (N1), 23 ... 2nd N phase conductor (N2), 31 ... 1st capacitor (C1), 31P ... Positive electrode Terminal, 31N ... Negative electrode terminal, 32 ... Second capacitor (C2), 32P ... Positive electrode terminal, 32N ... Negative electrode terminal, 33 ... Third capacitor (C3), 33P ... Positive electrode terminal, 33N ... Negative electrode terminal.

Claims (4)

The first conductor and the second conductor, which are at least two conductors having the first polarity among the positive electrode and the negative electrode,
A third conductor, which is arranged between the first conductor and the second conductor and is at least one conductor having a polarity different from the first polarity and having a second polarity, is provided.
The first conductor is connected to the first terminals at both ends of the first capacitor among the plurality of capacitors.
The second conductor is connected to the second terminals at both ends of the second capacitor among the plurality of capacitors.
The third conductor is a conductor unit connected to the third terminals at both ends of the first capacitor and connected to the fourth terminals at both ends of the second capacitor. According to claim 1, the number of connections of at least one terminal connected to the first conductor among the terminals of the plurality of capacitors and the number of connections of at least one terminal connected to the second conductor are the same. Described conductor unit. The first main surface of the two main surfaces of the third conductor and the main surface of the first conductor on the third conductor side face each other in the thickness direction of each other.
The conductor according to claim 1 or 2, wherein the second main surface of the two main surfaces of the third conductor and the main surface of the second conductor on the third conductor side face each other in the thickness direction of each other. unit. The surface area of each of the two main surfaces of the third conductor is the surface area of the main surface of the first conductor on the third conductor side and the surface area of the main surface of the second conductor on the third conductor side. The conductor unit according to claim 3, which is the same.

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