A bridge arm circuit for a motor drive circuit and a motor drive system

Abstract

This utility model discloses a bridge arm circuit and a motor drive system for a motor drive circuit. The bridge arm circuit includes a positive bus terminal, a negative bus terminal, an upper bridge arm switch, a lower bridge arm switch, and an energy storage filter capacitor. The input terminal of the upper bridge arm switch is connected to the positive bus terminal, and the output terminal is connected to the input terminal of the lower bridge arm switch. The connection between the output terminal of the upper bridge arm switch and the input terminal of the lower bridge arm switch is externally connected to the phase line of the motor. The output terminal of the lower bridge arm switch is connected to the negative bus terminal. The positive and negative bus terminals are arranged close to each other and opposite to each other. The energy storage filter capacitor is connected across the positive and negative bus terminals. By arranging the positive and negative bus terminals close to each other and opposite to each other, this utility model can reduce the loop area formed by the positive and negative bus terminals, and the path of AC and DC current through the energy storage filter capacitor is short, which can effectively reduce external electromagnetic radiation.

Description

Technical Field

[0001] This utility model relates to a bridge arm circuit of a motor drive circuit and a motor drive system, belonging to the field of motor drive. Background Technology

[0002] In the field of motor control, motor drive circuits are composed of half-bridges made of power semiconductor switching transistors such as MOSFETs and IGBTs. Currently, there are some problems with the spatial layout (i.e., the layout of the circuit board) of the bridge arm circuit of the motor drive circuit: the positive and negative terminals of the bridge arm circuit are located on opposite sides of the circuit board, and the remaining components are distributed on the circuit board between the positive and negative terminals. This layout results in significant electromagnetic radiation from the motor drive circuit. Utility Model Content

[0003] This invention provides a bridge arm circuit for a motor drive circuit and a motor drive system, which solves the problems disclosed in the background art.

[0004] According to one aspect of this application, a bridge arm circuit for a motor drive circuit is provided, including a bus positive terminal, a bus negative terminal, an upper bridge arm switch transistor, a lower bridge arm switch transistor, and an energy storage filter capacitor. The input terminal of the upper bridge arm switch transistor is connected to the bus positive terminal, the output terminal of the upper bridge arm switch transistor is connected to the input terminal of the lower bridge arm switch transistor, the connection between the output terminal of the upper bridge arm switch transistor and the input terminal of the lower bridge arm switch transistor is externally connected to the phase line of the motor, and the output terminal of the lower bridge arm switch transistor is connected to the bus negative terminal. The bus positive terminal and the bus negative terminal are arranged close to each other and opposite to each other. The energy storage filter capacitor is connected across the bus positive terminal and the bus negative terminal.

[0005] Furthermore, the circuit also includes a circuit board. The positive and negative terminals of the bus are distributed on the first side of the circuit board, and the upper half-bridge switch, the lower half-bridge switch, and the energy storage filter capacitor are distributed on the second side of the circuit board. The second side of the circuit board is provided with a positive terminal, a negative terminal, an output terminal, and a lower half-bridge terminal. The positive terminal is opposite to the positive terminal of the bus and connected through a via. The negative terminal is opposite to the negative terminal of the bus and connected through a via. The energy storage filter capacitor is connected between the positive and negative terminals. The output terminal is located on the side of the positive terminal away from the negative terminal. The input and output terminals of the upper half-bridge switch are connected to the positive terminal and the output terminal, respectively. One end of the lower half-bridge terminal is connected to the negative terminal, and the other end of the lower half-bridge terminal extends to the output terminal. The input and output terminals of the lower half-bridge switch are connected to the other end of the output terminal and the lower half-bridge terminal, respectively. The output terminal is connected to the phase line of the motor.

[0006] Furthermore, a high-frequency filter capacitor is provided between the positive electrode assembly and the lower bridge arm assembly. The pins of the high-frequency filter capacitor connected to the positive electrode assembly and the pins connected to the lower bridge arm assembly are respectively close to the input terminal of the upper bridge arm switch and the output terminal of the lower bridge arm switch.

[0007] Furthermore, if motor phase current sampling is required, one end of the lower bridge arm fitting is connected to the negative fitting via a phase current sampling resistor.

[0008] Furthermore, if motor phase current sampling is required, the output device is connected to the motor phase line via a Hall current detection device.

[0009] Furthermore, a conductive strip is fixed on the lower bridge arm fitting.

[0010] According to another aspect of this application, a motor drive system is provided, including a controller and multiple parallel motor drive circuits, wherein the bridge arm circuit in the motor drive circuit is the aforementioned bridge arm circuit, and the controller is connected to the input terminal of the switching transistor drive circuit in all motor drive circuits.

[0011] Furthermore, if there is a phase current sampling resistor between the lower bridge arm component and the negative terminal component of the bridge arm circuit, the phase current sampling resistor is connected to the controller through the signal processing module.

[0012] Furthermore, if there is a Hall current detection device between the output component of the bridge arm circuit and the corresponding motor phase line, the signal output terminal of the Hall current detection device is connected to the controller.

[0013] Furthermore, if it is necessary to sample the current passing through the system, the system also includes a bus negative input, and a bus current sampling resistor is provided between the bus negative input and the bus negative terminal.

[0014] The beneficial effects achieved by this utility model are as follows: 1. By arranging the positive and negative terminals of the busbar close to each other and opposite to each other, this utility model can reduce the loop area formed by the positive and negative terminals of the busbar, and the AC and DC current paths of the energy storage filter capacitor are short, which can effectively reduce external electromagnetic radiation; 2. This utility model sets a high-frequency filter capacitor between the positive terminal component and the lower bridge arm component that passes through it, and the pins at both ends of the high-frequency filter capacitor are close to the input terminal of the upper bridge arm switch and the output terminal of the lower bridge arm switch respectively, which can absorb high-frequency current in time, reduce electromagnetic interference, and the arrangement structure can reduce the loop path length of high-frequency signals, thus reducing electromagnetic interference. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the first structure of the bridge arm circuit;

[0016] Figure 2 This is a schematic diagram of the second structure of the bridge arm circuit;

[0017] Figure 3 This is a schematic diagram of the third structure of the bridge arm circuit;

[0018] Figure 4 This is a schematic diagram of the fourth structure of the bridge arm circuit;

[0019] Figure 5 This is a schematic diagram of the first structure of the motor drive system;

[0020] Figure 6 This is a schematic diagram of the second structure of the motor drive system. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] To address the issue of significant electromagnetic radiation in motor drive circuits, this application provides a novel bridge arm circuit for a motor drive circuit. This circuit may include at least a positive bus 2, a negative bus 1, an upper half-bridge switch 4, a lower half-bridge switch 5, and an energy storage filter capacitor 3. The input terminal of the upper half-bridge switch 4 is connected to the positive bus 2, and the output terminal of the upper half-bridge switch 4 is connected to the input terminal of the lower half-bridge switch 5. The connection between the output terminal of the upper half-bridge switch 4 and the input terminal of the lower half-bridge switch 5 is externally connected to the phase line of the motor. The output terminal of the lower half-bridge switch 5 is connected to the negative bus 1. The positive bus 2 and the negative bus 1 are arranged close to each other and opposite to each other. The energy storage filter capacitor 3 is connected across the positive bus 2 and the negative bus 1.

[0029] The aforementioned bridge arm circuit reduces the loop area formed by the positive bus 2 and the negative bus 1 by arranging them close together and opposite to each other. Furthermore, the path of AC current and DC current through the energy storage filter capacitor 3 is short, which can effectively reduce external electromagnetic radiation.

[0030] In terms of spatial layout, the specific structure of the aforementioned bridge arm circuit can be found in [reference needed]. Figure 1 All components of the circuit are distributed on the circuit board. The positive and negative bus terminals 2 and 1 are located on the first side of the circuit board. The upper half-bridge switch 4, the lower half-bridge switch 5, and the energy storage filter capacitor 3 are located on the second side of the circuit board. The energy storage filter capacitor 3 can be a large-capacity capacitor such as an electrolytic capacitor, solid-state capacitor, or film capacitor. On the second side of the circuit board, the positive terminal component 7, the negative terminal component 6, the output component 8, and the lower half-bridge component 9 are installed. The positive terminal component 7 is opposite to the positive bus terminal 2 and connected through a via. The negative terminal component 6 is connected to the negative bus terminal 1. Relatively and via a via, the energy storage filter capacitor 3 is connected across the positive terminal 7 and the negative terminal 6. The output terminal 8 is located on the side of the positive terminal 7 away from the negative terminal 6. The input and output terminals of the upper bridge arm switch 4 of the half-bridge are connected to the positive terminal 7 and the output terminal 8, respectively. One end of the lower bridge arm switch 9 is connected to the negative terminal 6, and the other end of the lower bridge arm switch 9 extends to the accessory of the output terminal 8. The input and output terminals of the lower bridge arm switch 5 of the half-bridge are connected to the other end of the output terminal 8 and the lower bridge arm switch 9, respectively. The output terminal 8 is externally connected to the phase line of the motor.

[0031] Figure 1 In this layout, each half-bridge is equipped with an energy storage filter capacitor 3, which effectively reduces the output impedance of the energy storage filter capacitor 3 and significantly reduces the voltage fluctuation between the positive and negative terminals of the bus; and Figure 1 This layout can also significantly reduce the loop area formed by busbar positive terminal 2 and busbar negative terminal 1, shortening the paths of AC and DC currents, thereby greatly reducing external electromagnetic radiation and improving circuit stability; in addition, Figure 1In the aforementioned structural layout, each half-bridge circuit makes full use of the copper plating and via technology on the front and back of the circuit board, resulting in a small circuit board area, strong heat dissipation performance, easy automated production, and low production cost.

[0032] It should be noted that the first and second sides of the circuit board can be the back and front sides of the circuit board, or the front and back sides, depending on the actual situation.

[0033] It should be noted that all components refer to copper plating on the circuit board. Figure 1 Taking the structure in the middle as an example, the positive electrode component 7 and the negative electrode component 6 can be rectangular positive electrode copper and rectangular negative electrode copper respectively. The rectangular positive electrode copper and the rectangular negative electrode copper are also relatively distributed. The output component 8 is a rectangular output copper, and the lower bridge arm component 9 is a long strip copper. The rectangular output copper is located on the side of the rectangular positive electrode copper away from the rectangular negative electrode copper. The rectangular output copper is parallel to the rectangular positive electrode copper. The distribution direction of the long strip copper is perpendicular to the bus positive electrode 2 and the bus negative electrode 1.

[0034] It should be noted that in some embodiments, the output connector 8 can also be laid on the first side of the circuit board. The output connectors 8 on both sides are connected through vias, which is equivalent to the two sides of the circuit board being connected in parallel, reducing resistance and increasing the output current capability.

[0035] It should be noted that, in order to facilitate the connection of the phase wire of the motor to the output adapter 8, an output interface 10, such as a plug or socket, will be directly opened on the output adapter 8 to facilitate the connection of the motor.

[0036] In some embodiments, see Figure 2 A high-frequency filter capacitor 13 is connected between the positive electrode assembly 7 and the lower bridge arm assembly 9. The high-frequency filter capacitor 13 can be a surface-mount capacitor, such as a film capacitor or a ceramic capacitor, which is beneficial for high-frequency filtering. The pins of the high-frequency filter capacitor 13 connected to the positive electrode assembly 7 and the pins connected to the lower bridge arm assembly 9 are respectively close to the input terminal of the upper bridge arm switch 4 and the output terminal of the lower bridge arm switch 5 of the half-bridge. The high-frequency filter capacitor 13 can absorb high-frequency current in time and reduce electromagnetic interference. This arrangement structure can reduce the loop path length of high-frequency signals and reduce electromagnetic interference.

[0037] In some embodiments, see also Figure 3 A conductive strip 12 is fixed on the lower bridge arm fitting 9. Since the fitting is copper-clad, and since simple copper cladding only has copper cladding on one side, the current conduction and heat dissipation capabilities can be enhanced by adding a metal conductive strip 12.

[0038] It should be noted that the setting of the high-frequency filter capacitor 13 and the conductive strip 12 can be determined according to the requirements. That is to say, in a bridge arm circuit, only the high-frequency filter capacitor 13 can be set, only the conductive strip 12 can be set, or both can be set.

[0039] It should be noted that since the motor drive circuit is used to drive the motor, the controller of the motor drive circuit needs to use phase current information. Therefore, a phase current sampling component is often added to the bridge arm circuit.

[0040] To accommodate motor phase current sampling, in some embodiments, see [link to relevant documentation]. Figure 3 One end of the lower bridge arm fitting 9 is connected to the negative fitting 6 through the phase current sampling resistor 14. When the current flows through the phase current sampling resistor 14, the voltage on the phase current sampling resistor 14 can be obtained, and the current sampling is indirectly achieved through the voltage.

[0041] In some embodiments, see Figure 4 The output component 8 is connected to the phase line of the motor through the Hall current detection device 15. Specifically, a Hall current detection chip or a through-hole Hall current sensor can be used. In order to facilitate the connection of the motor, an additional output interface component 16, i.e., output interface copper, can be laid on the second side of the circuit board. The output interface 10 is opened on the output interface copper. The output interface copper and the output component 8 (i.e., output copper) are connected through the Hall current detection device 15. Using the Hall current sampling method can separate large current and weak signal, and obtain a more stable current signal and better control effect.

[0042] It should be noted that, in order to protect the switching transistor in the bridge arm circuit, a protection device 11 is connected between the output terminal and the control terminal of the switching transistor. The protection device 11 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; for example, 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, preventing damage to the switching transistor under conditions such as electrostatic discharge and / or rapid current changes. The resistors and diodes can control the turn-on and turn-off speeds of the switching transistor, preventing damage. Of course, the protection device 11 can also have other connection methods, but since these are existing technologies, they will not be described in detail here.

[0043] The working process of the bridge arm circuit in the motor drive circuit is as follows: The controller sends a switching signal to the half bridge. This switching signal is adjusted by the switching transistor drive circuit and sends a switching drive voltage to the upper bridge arm switching transistor 4 and the lower bridge arm switching transistor 5 of the half bridge. This switching drive voltage is generally connected to the input terminal of the switching transistor through the protection device 11, driving the switching transistor to turn off and on. The switching transistor outputs or inputs current from the power supply and energy storage filter capacitor 3 through the positive terminal 2 and the negative terminal 1 of the bus, and releases or absorbs the current to the motor phase line.

[0044] Based on the above-described bridge arm circuit, this application also discloses a motor drive system, which may include at least a controller and multiple parallel motor drive circuits. The bridge arm circuit in the motor drive circuit adopts the above-described bridge arm circuit, and the controller is connected to the input terminal of the switching transistor drive circuit 17 in all motor drive circuits.

[0045] Taking a common three-phase system as an example, see [link / reference]. Figure 5 The system includes three parallel motor drive circuits. The bridge arm circuits of all motor drive circuits can be mounted on the same circuit board, with the distribution of the bridge arm circuit components as described previously. To achieve phase current sampling, a phase current sampling resistor 14 can be connected between the lower bridge arm component 9 and the negative terminal component 6 of the first and second corresponding bridge arm circuits. To obtain an effective signal, each phase current sampling resistor 14 is connected to the controller via a signal processing module 18. The signal processing module 18 primarily filters and amplifies the voltage signal on the phase current sampling resistor 14 using amplifiers, thus minimizing the path of the sampled weak model signal and effectively avoiding interference. Furthermore, the voltage signal from the phase current sampling resistor 14 to the signal processing module 18 is represented as a differential signal on the circuit board to enhance its anti-interference performance.

[0046] It should be noted that the three-way parallel motor drive circuit mainly consists of parallel connection of the positive bus 2 and the negative bus 1 in all bridge arm circuits. To facilitate sampling of the current passing through the system, a positive bus input 19 and a negative bus input 21 can be set on the same side of the positive bus 2 and the negative bus 1. All positive bus 2 are connected to the positive bus input 19, and all negative bus 1 are connected to the negative bus input 21. Corresponding interfaces are opened on the positive bus input 19 and the negative bus input 21. A bus current sampling resistor 20 is connected between the negative bus input 21 and the negative bus 1. Similarly, the bus current sampling resistor 20 is also connected to the controller through the signal processing module 18.

[0047] It should be noted that, similar to the protection of the switching transistor, a protection device 11 is also connected between the positive input 19 and the negative input 21 of the bus to protect the switching transistors and other components in the bridge arm circuit.

[0048] Let's take three-phase as an example again, see... Figure 6 Compared to Figure 5 , Figure 6 The two phase current sampling resistors 14 are replaced with Hall current detection devices 15 to detect the current. The Hall current detection devices 15 can be connected between the output component 8 of the first and third corresponding bridge arm circuits and the corresponding motor phase lines. The Hall current detection devices 15 detect the phase current flowing through the motor phase lines and transmit the signal containing the phase current information to the controller.

[0049] The working process of the motor drive system is as follows: The controller obtains the current information flowing through the motor phase line from the phase current sampling resistor 14, the bus current sampling resistor 20, and the Hall current detection device 15, either individually or in combination. In conjunction with the position signal of the motor rotor, and through a set algorithm, it controls the closing and opening of each switch transistor, thereby controlling the magnitude and phase of the phase current flowing through the motor phase line to form a current closed-loop control.

[0050] 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 bridge arm circuit for a motor drive circuit, characterized in that, It includes the positive and negative terminals of the busbar, the upper and lower half-bridge switch transistors, and the energy storage filter capacitor. The input terminal of the upper half-bridge switch transistor is connected to the positive terminal of the busbar, and the output terminal of the upper half-bridge switch transistor is connected to the input terminal of the lower half-bridge switch transistor. The connection between the output terminal of the upper half-bridge switch transistor and the input terminal of the lower half-bridge switch transistor is connected to the phase line of the motor. The output terminal of the lower half-bridge switch transistor is connected to the negative terminal of the busbar. The positive and negative terminals of the busbar are arranged close to each other and opposite to each other. The energy storage filter capacitor is connected across the positive and negative terminals of the busbar.

2. The circuit according to claim 1, characterized in that, The circuit also includes a circuit board. The positive and negative terminals of the bus are distributed on the first side of the circuit board. The upper half-bridge switch, the lower half-bridge switch, and the energy storage filter capacitor are distributed on the second side of the circuit board. The second side of the circuit board is provided with a positive terminal, a negative terminal, an output terminal, and a lower half-bridge terminal. The positive terminal is opposite to the positive terminal of the bus and connected through a via. The negative terminal is opposite to the negative terminal of the bus and connected through a via. The energy storage filter capacitor is connected between the positive and negative terminals. The output terminal is located on the side of the positive terminal away from the negative terminal. The input and output terminals of the upper half-bridge switch are connected to the positive terminal and the output terminal, respectively. One end of the lower half-bridge terminal is connected to the negative terminal, and the other end of the lower half-bridge terminal extends to the output terminal. The input and output terminals of the lower half-bridge switch are connected to the output terminal and the other end of the lower half-bridge terminal, respectively. The output terminal is connected to the phase wire of the motor.

3. The circuit according to claim 2, characterized in that, A high-frequency filter capacitor is provided between the positive terminal and the lower bridge arm terminal. The pins of the high-frequency filter capacitor connected to the positive terminal and the pins connected to the lower bridge arm terminal are respectively close to the input terminal of the upper bridge arm switch and the output terminal of the lower bridge arm switch.

4. The circuit according to claim 2, characterized in that, If motor phase current sampling is required, one end of the lower bridge arm fitting is connected to the negative fitting through a phase current sampling resistor.

5. The circuit according to claim 2, characterized in that, If motor phase current sampling is required, the output device is connected to the motor phase line via a Hall current detection device.

6. The circuit according to claim 2, characterized in that, A conductive strip is fixed on the lower bridge arm fitting.

7. A motor drive system, characterized in that, It includes a controller and multiple parallel motor drive circuits, wherein the bridge arm circuit in the motor drive circuit is the circuit described in any one of claims 1 to 6, and the controller is connected to the input terminal of the switching transistor drive circuit in all motor drive circuits.

8. The system according to claim 7, characterized in that, If there is a phase current sampling resistor between the lower bridge arm and the negative terminal of the bridge arm circuit, the phase current sampling resistor is connected to the controller through the signal processing module.

9. The system according to claim 7, characterized in that, If a Hall current detection device exists between the output component of the bridge arm circuit and the corresponding motor phase line, the signal output terminal of the Hall current detection device is connected to the controller.

10. The system according to claim 7, characterized in that, If it is necessary to sample the current passing through the system, the system also includes a bus negative input, and a bus current sampling resistor is provided between the bus negative input and the bus negative terminal.

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