A power conversion circuit and system

Abstract

This utility model discloses a power conversion circuit and system. The circuit includes an upper bridge arm, a lower bridge arm, and a bridge arm connecting piece. The input terminal of the upper bridge arm is connected to the positive terminal of the bus. The output terminal of the upper bridge arm is connected to the bridge arm connecting piece via an output piece. The bridge arm connecting piece is connected to the input terminal of the lower bridge arm via an input piece. The output terminal of the lower bridge arm is connected to the negative terminal of the bus. An energy storage filter capacitor is connected between the positive and negative terminals of the bus. The positive and negative terminals of the bus are arranged opposite to each other. This utility model reduces the loop area formed by the positive and negative terminals of the bus, effectively reducing external electromagnetic radiation, thereby improving stability and power density.

Description

Technical Field

[0001] This utility model relates to a power conversion circuit and system, belonging to the field of circuit design. Background Technology

[0002] In fields such as power conversion and motor control, power conversion circuits composed of half-bridges made of power semiconductors such as MOSFETs and IGBTs are required. For example... Figure 1 As shown, the power conversion circuit mainly includes the positive bus 1, upper bridge arm 8 (composed of three power semiconductors connected in parallel), output chip 4, bridge arm connecting chip 6, lower bridge arm 9 (composed of three power semiconductors connected in parallel), input chip 5, negative bus 7, and energy storage filter capacitor 2. The input terminal of upper bridge arm 8 is connected to the positive bus 1. The output terminal of upper bridge arm 8 is connected to the input terminal of lower bridge arm 9 through output chip 4, bridge arm connecting chip 6, and input chip 5. The output terminal of lower bridge arm 9 is connected to the negative bus 7. The energy storage filter capacitor 2 is connected between the positive bus 1 and the negative bus 7. The power conversion circuit is similar in spatial layout. Figure 1 Specifically, the positive bus 1 and negative bus 7 are located on both sides, the output plate 4 and input plate 5 are located in the middle, the upper bridge arm 8 is located between the positive bus 1 and the output plate 4, and the lower bridge arm 9 is located between the negative bus 7 and the input plate 5. This spatial layout results in significant electromagnetic radiation from the power conversion circuit. Utility Model Content

[0003] This invention provides a power conversion circuit and system that solves the problems disclosed in the background art.

[0004] According to one aspect of this application, a power conversion circuit is provided, including an upper bridge arm, a lower bridge arm, and a bridge arm connecting piece. The input terminal of the upper bridge arm is connected to the positive terminal of a bus, the output terminal of the upper bridge arm is connected to the bridge arm connecting piece through an output piece, the bridge arm connecting piece is connected to the input terminal of the lower bridge arm through an input piece, the output terminal of the lower bridge arm is connected to the negative terminal of a bus, and an energy storage filter capacitor is connected between the positive and negative terminals of the bus. The positive and negative terminals of the bus are arranged opposite to each other.

[0005] Furthermore, the upper bridge arm and output plate are sequentially distributed on the side of the bus positive terminal away from the bus negative terminal, and the lower bridge arm and input plate are sequentially distributed on the side of the bus negative terminal away from the bus positive terminal. The energy storage filter capacitor is connected between the bus positive terminal and the bus negative terminal.

[0006] Furthermore, all components of the circuit are located on the same side of the circuit board, with the bridge arm connecting piece spanning between the output piece and the input piece.

[0007] Furthermore, the bridge arm connecting piece has a through hole facing the energy storage filter capacitor, and the end of the energy storage filter capacitor passes through the through hole.

[0008] Furthermore, a capacitor adapter plate is connected between the positive and negative terminals of the busbar, and the energy storage and filtering capacitor is set on the capacitor adapter plate and connected to the positive and negative terminals of the busbar through the capacitor adapter plate.

[0009] Furthermore, heat-conducting components are provided between the bridge arm connecting piece and the power semiconductor of the upper bridge arm, and between the bridge arm connecting piece and the power semiconductor of the lower bridge arm.

[0010] Furthermore, the bridge arm connector, output connector, and input connector of the circuit are located on one side of the circuit board, while the remaining components of the circuit are located on the other side of the circuit board. The upper bridge arm output terminal is connected to the output connector through a via, and the lower bridge arm input terminal is connected to the input connector through a via. The bridge arm connector is formed by copper plating or metal surface mounting.

[0011] According to another aspect of this application, a power conversion system is provided, including a control module and several power conversion circuits, wherein the power semiconductor control terminals of the power conversion circuits are connected to the control module, the positive terminals of the buses of all power conversion circuits are connected in parallel, and the negative terminals of the buses of all power conversion circuits are connected in parallel.

[0012] Furthermore, the control module and all power conversion circuits are arranged in an array on the same circuit board.

[0013] Furthermore, the control module and various power conversion circuits are distributed on different circuit boards, and the circuit boards containing the power conversion circuits are stacked vertically.

[0014] The beneficial effects achieved by this utility model are as follows: By arranging the positive and negative poles of the busbar opposite to each other, this utility model can reduce the loop area formed by the positive and negative poles of the busbar, effectively reduce external electromagnetic radiation, and thus help improve stability and power density. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of a power conversion circuit;

[0016] Figure 2 This is a schematic diagram of the first distribution of the power conversion circuit;

[0017] Figure 3 This is a second distributed side view of the power conversion circuit;

[0018] Figure 4 This is a top view of the second distribution of the power conversion circuit;

[0019] Figure 5 This is a schematic diagram of the third distribution of the power conversion circuit;

[0020] Figure 6 This is a schematic diagram of the fourth distribution of the power conversion circuit;

[0021] Figure 7 This is a schematic diagram of the connection of the energy storage filter capacitor;

[0022] Figure 8 This is a schematic diagram showing the distribution of the protection devices;

[0023] Figure 9 This is a schematic diagram of the first distribution of the power conversion system;

[0024] Figure 10 This is a schematic diagram of the second distribution of the power conversion system;

[0025] Figure 11 This is a third distributed side view of the power conversion system;

[0026] Figure 12 This is a top view of the third distribution of the power conversion system. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application.

[0029] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0030] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0031] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0032] It should be noted that similar symbols and letters in the following figures represent similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0033] Furthermore, in the description of the embodiments of this application, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features.

[0034] See Figure 2 , Figure 2 This is a first schematic diagram of a power conversion circuit provided in an embodiment of this application. Figure 2 The connection relationship between the various components and Figure 1 The structure mainly consists of an upper bridge arm 8, a lower bridge arm 9, and a bridge arm connecting piece 6. The input terminal of the upper bridge arm 8 is connected to the positive terminal 1 of the busbar. The output terminal of the upper bridge arm 8 is connected to the bridge arm connecting piece 6 via an output piece 4. The bridge arm connecting piece 6 is connected to the input terminal of the lower bridge arm 9 via an input piece 5. The output terminal of the lower bridge arm 9 is connected to the negative terminal 7 of the busbar. An energy storage filter capacitor 2 is connected between the positive terminal 1 and the negative terminal 7 of the busbar to effectively reduce electromagnetic radiation. Figure 2 The arrangement of the positive pole 1 and negative pole 7 of the busbar relative to each other can reduce the loop area formed by the positive pole 1 and negative pole 7, effectively reducing external electromagnetic radiation, thereby improving stability and power density.

[0035] It should be noted that if the distance between the positive terminal 1 and the negative terminal 7 of the busbar is too large, it will increase the input impedance of the energy storage filter capacitor 2, reducing its filtering effect. Conversely, if the width between the positive terminal 1 and the negative terminal 7 of the busbar becomes smaller, the resistance will increase, leading to increased power consumption. Therefore, the distance between the positive terminal 1 and the negative terminal 7 of the busbar should not be too large or too small; generally, the distance should not exceed twice the distance between the positive and negative terminals of the energy storage filter capacitor 2.

[0036] To ensure a compact overall circuit and reduce size, in some embodiments, an upper bridge arm 8 and an output plate 4 are sequentially distributed on the side of the bus positive terminal 1 away from the bus negative terminal 7, and a lower bridge arm 9 and an input plate 5 are sequentially distributed on the side of the bus negative terminal 7 away from the bus positive terminal 1. An energy storage filter capacitor 2 is connected across the bus positive terminal 1 and the bus negative terminal 7.

[0037] by Figure 2For example, the following components are arranged in order from top to bottom: output chip 4, upper bridge arm 8 (i.e., upper bridge arm 8 power semiconductor array), bus positive terminal 1, bus negative terminal 7, lower bridge arm 9 (i.e., lower bridge arm 9 power semiconductor array), and input chip 5. Output chip 4 is electrically connected to the output terminals of each power semiconductor in upper bridge arm 8. The input terminals of each power semiconductor in upper bridge arm 8 are electrically connected to bus positive terminal 1. Bus positive terminal 1 is electrically connected to the positive terminal of energy storage filter capacitor 2. The negative terminal of energy storage filter capacitor 2 is electrically connected to bus negative terminal 7. Bus negative terminal 7 is electrically connected to the output terminals of each power semiconductor in lower bridge arm 9. The input terminals of each power semiconductor in lower bridge arm 9 are electrically connected to input chip 5. Energy storage filter capacitor 2 is connected across bus positive terminal 1 and bus negative terminal 7.

[0038] It should be noted that electrical connections can be copper-clad connections located on the same side of the circuit board. Copper-clad connections can be made by surface-mount metal sheets or tin plating, which can further reduce conduction resistance.

[0039] In some embodiments, such as Figure 3 and 4 As shown, all components of the power conversion circuit can be located on the same side of the circuit board. In this case, the bridge arm connector 6 can be connected between the output plate 4 and the input plate 5. The bridge arm connector 6 can be electrically connected to the output plate 4 and the input plate 5 through surface mount technology (SMT) and / or bolt connection. This distribution of bridge arm connector 6 is similar to a top cover, which can cover the main components of the circuit, such as power semiconductors, and provide them with a certain degree of protection.

[0040] It should be noted that in some embodiments, the bridge arm connecting piece 6 may also have a through hole 12 facing the energy storage filter capacitor 2. The end of the energy storage filter capacitor 2 passes through the through hole 12. This through hole 12 is generally adapted to the energy storage filter capacitor 2. The through hole 12 can prevent the energy storage filter capacitor 2 from shaking and being damaged due to vibration.

[0041] In addition to protecting the power semiconductor, the top-cover type bridge arm connector 6 can also serve as a heat dissipation component. It only requires forming a heat conduction channel between the power semiconductor and the bridge arm connector 6. Therefore, in some embodiments, a heat conduction component 10, such as a thermal pad, can be fixed between the bridge arm connector 6 and the power semiconductor of the upper bridge arm 8, or between the bridge arm connector 6 and the power semiconductor of the lower bridge arm 9. This can effectively transfer the heat of the power semiconductor to the bridge arm connector 6, thereby improving the heat dissipation performance of the power semiconductor.

[0042] To further enhance heat dissipation and improve the strength of the bridge arm connecting piece 6, in some embodiments, reinforcing ribs 11 can be provided on the bridge arm connecting piece 6, such as... Figure 4A reinforcing rib is provided along the length of the bridge arm connecting piece 6. This reinforcing rib not only enhances the mechanical strength of the bridge arm connecting piece 6, but also increases the area of ​​the bridge arm connecting piece 6, thereby improving heat dissipation.

[0043] It should be noted that the distribution of the bridge arm connecting pieces 6 can also be as follows: Figure 5 As shown, the bridge arm connecting piece 6 is divided into three sections. The first connecting section 61 is fixed to the output piece 4 by bolts, the third connecting section 63 is fixed to the input piece 5 by bolts, and the second connecting section 62 is located on one side of the circuit board and connects the first connecting section 61 and the third connecting section 63. Some bolts are also fixed on the second connecting section 62, which can be used to connect the external output cables. This bridge arm connecting piece 6 has a simple structure and low cost.

[0044] It should be noted that, in some embodiments, the distribution of the bridge arm connecting pieces 6 can also be as follows: Figure 6 As shown, the bridge arm connector 6, output connector 4, and input connector 5 of the power conversion circuit are located on one side of the circuit board, while the remaining components of the circuit are located on the other side. The output terminal of the upper bridge arm 8 is connected to the output connector 4 through via 13a, and the input terminal of the lower bridge arm 9 is connected to the input connector 5 through via 13b. The bridge arm connector 6 is formed by copper plating or metal surface mounting, and it connects to the output connector 4 and the input connector 5. This structure, by using a copper plating or metal surface mounting method for the bridge arm connector 6 on a printed circuit board, eliminates the need for a traditional bridge arm connector 6, thus reducing costs.

[0045] Figure 6 In this circuit board, a double-sided copper-clad circuit board is used. Assume that a bridge arm connecting piece 6, an output piece 4, and an input piece 5 are set on the back of the circuit board, and the remaining components are set on the front. The output piece 4 on the front and the corresponding back can be connected through a via 13a, and the input piece 5 on the front and the corresponding back can be connected through a via 13b. The bridge arm connecting piece 6 connects the output piece 4 and the input piece 5 on the back.

[0046] Furthermore, the power semiconductor of the upper bridge arm is connected to the copper plating on the back side through via 13c, and the power semiconductor of the lower bridge arm is connected to the input chip 5 on the back side through via 13b. This conducts the heat of the power semiconductor to the back side, increasing the heat dissipation area. If a thermal pad and heat sink are further provided on the back side, the heat dissipation capacity can be further enhanced. In addition, conductive and thermally conductive materials are filled in vias 13a, 13b, and 13c, which can further enhance the conductivity and thermal conductivity.

[0047] It should be noted that the aforementioned energy storage and filtering capacitor 2 includes a large-capacity electrolytic capacitor and a small-capacity surface-mount capacitor. The former is used for energy storage and filtering, while the latter is used to eliminate high-frequency interference.

[0048] If the circuit board is a single-sided board (such as an aluminum substrate), through-hole capacitors cannot be used on these boards. Therefore, a capacitor adapter board can be connected between the positive and negative terminals of the bus. The energy storage and filtering capacitor is fixed on the capacitor adapter board and connected to the positive and negative terminals of the bus through the adapter board. Specifically... Figure 7 As shown, the through-hole capacitors need to be plugged into the capacitor adapter board 14 (double-sided board) first, and then the capacitor adapter board 14 is surface-mounted or bolted to the circuit board.

[0049] The capacitor adapter board 14 can be a double-sided copper-clad circuit board. The front and back sides of the capacitor adapter board 14 are provided with positive and negative terminals. The same polarity is connected through vias (the vias are filled with a conductor, such as copper). The energy storage filter capacitor 2 is fixed on the front side of the capacitor adapter board 14. The positive and negative terminals of the energy storage filter capacitor 2 are connected to the positive and negative terminals of the capacitor adapter board 14, respectively. The capacitor adapter board 14 is connected to the circuit board of the power conversion circuit by SMT (surface mount technology) or bolt connection, so that the positive and negative terminals of the capacitor adapter board 14 are electrically connected to the positive terminal 1 and the negative terminal 7 of the bus, respectively.

[0050] It should be noted that, in order to enhance the protection of the power semiconductor drive, a protection device 15 can be connected between the output terminal and the control terminal of the power semiconductor, such as... Figure 8 As shown, the protection device 15 can be a device composed of capacitors, voltage limiting semiconductors (ZnD, ESD, TVS, etc.), resistors, diodes, etc. There are various circuit configurations for this device; as shown, it can be a device composed of capacitors and diodes connected in parallel. The capacitors and voltage limiting semiconductors can absorb and suppress the voltage at the control terminal of the power semiconductor, preventing damage to the power semiconductor under conditions such as static electricity and / or rapid current changes. The resistors and diodes can control the turn-on and turn-off speeds of the power semiconductor, preventing damage. Of course, the protection device 15 can also have other connection methods, but since these are existing technologies, they will not be described in detail here.

[0051] Based on the power conversion circuit described above, this application also discloses a power conversion system, see [link to relevant documentation]. Figure 9 , Figure 9 This is a first distribution diagram of a power conversion system provided in an embodiment of this application. The system may include at least a control module and several power conversion circuits. The power semiconductor control terminal of the power conversion circuit is connected to the control module. The positive terminals 1 of all power conversion circuits are connected in parallel, and the negative terminals 7 of all power conversion circuits are connected in parallel.

[0052] The number of power conversion circuits is related to the number of phases. If it is a three-phase AC motor control, then three power conversion circuits are used. See [link to details] for more information. Figure 9 .

[0053] The control module and all power conversion circuits can be arranged in an array on the same circuit board, which can reduce system complexity and cost. Figure 9 The control module and three power conversion circuits are arranged in two rows and two columns, with the positive bus interface 17 and the negative bus interface 18 preferably located on the middle half-bridge, and the output line interface 16 preferably located on the output chip 4. Of course, the arrangement of the control module and the three power conversion circuits can also be as follows... Figure 10 As shown, the three power conversion circuits are arranged in one row, and the control module is located in the second row.

[0054] In some embodiments, the control module and each power conversion circuit can be distributed on different circuit boards, and the circuit boards containing the power conversion circuits can be stacked vertically. This can reduce the system's spatial volume and avoid the disadvantage of excessive projected area caused by arranging them on the same circuit board.

[0055] See Figure 11 and 12 The three power conversion circuits are respectively mounted on three circuit boards, which are defined as conversion circuit boards 19. The control module is mounted on a separate circuit board, which is defined as control board 20. The three conversion circuit boards 19 are stacked vertically, and the control board 20 is located on one side of the stack and is arranged vertically along the positive terminal 1 and the negative terminal 7 of the busbar. This distribution minimizes the wiring and makes it easy for the output lines of multiple power conversion circuits and the cables of the busbar to pass through the current sensor mounted on the control board 20.

[0056] Assuming the conversion circuit board 19 uses Figure 3 In order to facilitate heat dissipation of the conversion circuit board 19, a half-bridge heat sink 21 can be attached to the back of the conversion circuit board 19, and each half-bridge heat sink 21 is connected to a main heat sink 22. The main heat sink 22 can be connected to the housing to further improve heat dissipation performance.

[0057] The stacked conversion circuit boards 19 can be connected to their respective bus positive terminal 1 and bus negative terminal 7 through conductive posts 23. The positive and negative terminals of the external power supply are preferentially connected to the bus positive terminal 1 and bus negative terminal 7 through the middle layer to minimize the loop, loss and interference.

[0058] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A power conversion circuit, comprising an upper bridge arm, a lower bridge arm, and a bridge arm connecting piece, wherein the input terminal of the upper bridge arm is connected to the positive terminal of a bus, the output terminal of the upper bridge arm is connected to the bridge arm connecting piece via an output piece, the bridge arm connecting piece is connected to the input terminal of the lower bridge arm via an input piece, the output terminal of the lower bridge arm is connected to the negative terminal of a bus, and an energy storage filter capacitor is connected between the positive and negative terminals of the bus, characterized in that... The positive and negative terminals of the busbar are arranged opposite each other.

2. The circuit according to claim 1, characterized in that, The upper bridge arm and output plate are arranged sequentially on the side of the busbar positive terminal away from the busbar negative terminal, and the lower bridge arm and input plate are arranged sequentially on the side of the busbar negative terminal away from the busbar positive terminal. The energy storage filter capacitor is connected between the busbar positive terminal and the busbar negative terminal.

3. The circuit according to claim 2, characterized in that, All components of the circuit are located on the same side of the circuit board, and the bridge arm connector spans between the output and input plates.

4. The circuit according to claim 3, characterized in that, The bridge arm connecting piece has a through hole facing the energy storage filter capacitor, and the end of the energy storage filter capacitor passes through the through hole.

5. The circuit according to claim 1 or 4, characterized in that, A capacitor adapter plate is connected between the positive and negative terminals of the busbar. The energy storage and filtering capacitor is set on the capacitor adapter plate and is connected to the positive and negative terminals of the busbar through the capacitor adapter plate.

6. The circuit according to claim 3, characterized in that, Heat-conducting components are provided between the bridge arm connecting piece and the power semiconductor of the upper bridge arm, and between the bridge arm connecting piece and the power semiconductor of the lower bridge arm.

7. The circuit according to claim 2, characterized in that, The bridge arm connector, output connector, and input connector of the circuit are located on one side of the circuit board, and the remaining components of the circuit are located on the other side of the circuit board. The upper bridge arm output terminal is connected to the output connector through a via, and the lower bridge arm input terminal is connected to the input connector through a via. The bridge arm connector is formed by copper plating or metal surface mounting.

8. A power conversion system, characterized in that, It includes a control module and several circuits as described in any one of claims 1 to 7, wherein the power semiconductor control terminal of the power conversion circuit is connected to the control module, the positive terminals of the buses of all power conversion circuits are connected in parallel, and the negative terminals of the buses of all power conversion circuits are connected in parallel.

9. The system according to claim 8, characterized in that, The control module and all power conversion circuits are arranged in an array on the same circuit board.

10. The system according to claim 8, characterized in that, The control module and various power conversion circuits are distributed on different circuit boards, which are stacked vertically.

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