Supporting capacitor module, motor controller, electric drive system, automobile and electronic equipment

Abstract

The embodiment of the invention provides a supporting capacitor module, a motor controller, an electric drive system, an automobile and electronic equipment. The supporting capacitor module comprises a first current path passing through the first capacitor bank and a second current path passing through the second capacitor bank. The impedance of the first current path is smaller than that of the second current path in a first frequency interval; in a second frequency interval, the impedance of the first current path is greater than that of the second current path; the first frequency interval is smaller than the second frequency interval; a stray inductance of the first current path is greater than a stray inductance of the second current path. In the ripple current generated when the power switch is turned off, the low-frequency current component mainly passes through the first current path and is absorbed by the first capacitor group, and the high-frequency current component mainly passes through the second current path and is absorbed by the second capacitor group, so that the turn-off instantaneous voltage of the high-frequency power switch can be better stabilized.

Description

Technical Field

[0001] This application relates to the field of electronic device technology, specifically to a supporting capacitor module, motor controller, electric drive system, automobile and electronic equipment. Background Technology

[0002] A converter is a device that changes the voltage, frequency, number of phases, and other electrical quantities or characteristics of a power supply system, and it has wide applications in many fields. In practical applications, some situations require converting AC power to DC power, which is the case with rectifier circuits. In other situations, DC power needs to be converted to AC power; this reverse process, corresponding to rectification, is defined as an inverter circuit.

[0003] Taking inverter circuits as an example, in the photovoltaic field, inverter circuits are needed to convert the direct current (DC) generated by solar panels into alternating current (AC) for grid connection; in new energy vehicles, inverter circuits are needed to convert the DC power from batteries into AC power to drive the motor. Inverter circuits typically include multiple power switches. High-frequency control of the switching on and off of different power switches generates currents in different directions, thus outputting AC power. Frequent switching on and off of the power switches generates harmonic currents, and changes in these harmonic currents can cause voltage fluctuations. Therefore, supporting capacitors need to be added across the DC power supply to absorb harmonic currents and stabilize the DC voltage.

[0004] However, with the development of related technologies, the power switches currently in use, such as silicon carbide metal-oxide-semiconductor field-effect transistors (SiCMOSFETs), operate at high frequencies and have fast switching speeds. When these high-frequency, high-speed power switches are used in conjunction with existing supporting capacitors, the excessively high stray inductance of the circuit often leads to excessively high voltage spikes at the moment of power switch turn-off, causing problems such as increased power loss, reduced conversion efficiency, and decreased power switch reliability. Summary of the Invention

[0005] This application provides a support capacitor module, motor controller, electric drive system, automobile and electronic equipment, which can solve the problem that existing support capacitors cannot stabilize the turn-off instantaneous voltage of high-frequency power switches.

[0006] In a first aspect, a supporting capacitor module is provided, comprising: one or more pairs of terminals; each pair of terminals including a first terminal and a second terminal; each pair of terminals for connecting to a power module, the power module including multiple power switches; a first capacitor group including one or more capacitors, one end connected to all the first terminals and the other end connected to all the second terminals; a second capacitor group including one or more capacitors, one end connected to all the first terminals and the other end connected to all the second terminals; a first current path is formed from the first terminal to the second terminal via the first capacitor group; a second current path is formed from the first terminal to the second terminal via the second capacitor group; within a first frequency range, the impedance of the first current path is less than the impedance of the second current path; within a second frequency range, the impedance of the first current path is greater than the impedance of the second current path; the first frequency range is less than the second frequency range; and the stray inductance of the first current path is greater than the stray inductance of the second current path. In this implementation, the first frequency range is a low-frequency range, the second frequency range is a high-frequency range, and the first frequency range being less than the second frequency range means that the maximum value of the first frequency range is less than the minimum value of the second frequency range. The ripple current generated when the power switch is turned off contains both low-frequency and high-frequency current components. Since the impedance of the first current path is lower in the low-frequency range, and the impedance of the second current path is lower in the high-frequency range, the low-frequency current component mainly passes through the first current path and is absorbed by the first capacitor bank, while the high-frequency current component mainly passes through the second current path and is absorbed by the second capacitor bank. The instantaneous voltage at turn-off of the high-frequency power switch is determined by both the frequency of the ripple current and the magnitude of the stray inductance of the current path. The low-frequency current component has a smaller impact on the instantaneous voltage fluctuation, while the high-frequency current component has a larger impact. Therefore, compared to a scheme that uses a single capacitor bank to absorb both low-frequency and high-frequency current components, the supporting capacitor module in this implementation, by designing a second current path with lower high-frequency impedance and smaller stray inductance, results in smaller instantaneous voltage fluctuations during the absorption of the high-frequency current component by the second capacitor bank, thus better stabilizing the instantaneous voltage at turn-off of the high-frequency power switch.

[0007] In conjunction with the first aspect, in a first possible implementation of the first aspect, the resonant frequency of the first current path is located within the first frequency range, and the resonant frequency of the second current path is located within the second frequency range; and / or within the first frequency range, the impedance of the first capacitor bank is less than the impedance of the second capacitor bank; and within the second frequency range, the impedance of the first capacitor bank is greater than the impedance of the second capacitor bank. In this implementation, since the resonant frequency of the first current path is located within the first frequency range, the impedance of the first current path has a minimum value within the first frequency range; and since the resonant frequency of the second current path is located within the second frequency range, the impedance of the second current path has a minimum value within the second frequency range. This makes it easier to achieve the following: within the first frequency range, the impedance of the first current path is less than the impedance of the second current path; and within the second frequency range, the impedance of the first current path is greater than the impedance of the second current path. Specifically, the resonant frequency of the first current path is related to its equivalent capacitance and stray inductance, and the resonant frequency of the second current path is related to its equivalent capacitance and stray inductance. Therefore, by designing and testing the equivalent capacitance and stray inductance of the first and second current paths respectively, it is possible to control the resonant frequency of the first current path to be within a first frequency range and the resonant frequency of the second current path to be within a second frequency range, while ensuring that the stray inductance of the first current path is greater than that of the second current path. Furthermore, the first current path mainly includes a first terminal, a positive busbar, a first capacitor bank, a negative busbar, and a second terminal, and the second current path mainly includes a first terminal, a positive busbar, a second capacitor bank, a negative busbar, and a second terminal. The impedances of the first, positive, negative, and second terminals are relatively low, and the impedances of the first and second current paths are mainly determined by the impedances of the first and second capacitor banks, respectively. Therefore, by controlling the impedance of the first capacitor bank to be less than the impedance of the second capacitor bank within the first frequency range, and the impedance of the first capacitor bank to be greater than the impedance of the second capacitor bank within the second frequency range, it is easier to achieve the impedance of the first current path to be less than the impedance of the second current path within the first frequency range, and the impedance of the first current path to be greater than the impedance of the second current path within the second frequency range.

[0008] In conjunction with the first aspect and the first possible implementation of the first aspect, in the second possible implementation of the first aspect, the equivalent capacitance of the first capacitor bank is greater than the equivalent capacitance of the second capacitor bank. Since the low-frequency current component is greater than the high-frequency current component in the ripple current generated when the power switch is turned off, this implementation provides a first capacitor bank with a larger capacitance value, which can effectively absorb the low-frequency current component. Furthermore, a larger capacitance value usually results in a larger equivalent series inductance. This implementation provides a second capacitor bank with a smaller capacitance value, which can reduce the equivalent series inductance of the second capacitor bank, thereby making it easier to control the stray inductance of the second current path to be less than the stray inductance of the first current path.

[0009] In conjunction with the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the first capacitor bank includes at least one of film capacitors and electrolytic capacitors; and / or the second capacitor bank includes at least one of ceramic capacitors and film capacitors. Film capacitors and electrolytic capacitors typically have large capacitance values, which is beneficial for effectively absorbing large amounts of low-frequency current components. Although the equivalent series inductance of film capacitors and electrolytic capacitors is typically large, it is mainly used to absorb low-frequency current components, thus it will not cause large fluctuations in the turn-off instantaneous voltage of the high-frequency power switch. Ceramic capacitors have smaller equivalent series inductance, which can reduce the fluctuations in the turn-off instantaneous voltage of the high-frequency power switch caused by high-frequency current components. Although the capacitance value of ceramic capacitors is typically small, the high-frequency current components are fewer, therefore ceramic capacitors can meet the requirement of absorbing high-frequency current components.

[0010] In conjunction with the first aspect, or any of the first to third possible implementations of the first aspect, in the fourth possible implementation of the first aspect, the equivalent series inductance of the first capacitor bank is greater than the equivalent series inductance of the second capacitor bank; and / or the length of the first current path is greater than the length of the second current path; and / or the magnetic coupling coefficient of the second current path is greater than the magnetic coupling coefficient of the first current path. The stray inductance of the first current path mainly includes two parts: the equivalent series inductance of the first capacitor bank and the stray inductance of the lines of the first current path (i.e., the portions of the positive and negative busbars located in the first current path, and the connections between the first terminal, positive busbar, first capacitor bank, negative busbar, second terminal, etc.). The longer the length of the first current path, the greater the stray inductance of the lines of the first current path. The magnetic coupling coefficient of the first current path is determined by factors such as the current direction, spacing, and overlapping area size of different segments of the first current path; the smaller the magnetic coupling coefficient of the first current path, the greater the stray inductance of the lines of the first current path. Similarly, the stray inductance of the second current path mainly consists of two parts: the equivalent series inductance of the second capacitor bank, and the stray inductance of the second current path lines (i.e., the portions of the positive and negative busbars located within the second current path, and the connections between the first terminal, positive busbar, second capacitor bank, negative busbar, and second terminal). The shorter the length of the second current path, the smaller the stray inductance of the second current path lines. The magnetic coupling coefficient of the second current path is determined by factors such as the current direction, spacing, and overlapping area size of different sections of the second current path; the larger the magnetic coupling coefficient of the second current path, the smaller the stray inductance of the second current path lines. Therefore, this implementation method makes it easier to achieve a stray inductance in the first current path greater than that in the second current path.

[0011] In conjunction with the first aspect, or any of the first to fourth possible implementations of the first aspect, in the fifth possible implementation of the first aspect, the ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each power switch is 0.5-1.5; or the ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each power switch is 0.8-1.2; or the ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each power switch is 0.9-1.1. During operation, each power switch needs to be periodically turned on and off. When the power switch is turned on, the current rises rapidly from 0 to its peak value; when the power switch is turned off, the current drops rapidly from its peak value to 0. Accordingly, the waveform of the current of the power switch over time is a periodic trapezoidal wave. The turn-off current fall-edge time of a power switch refers to the time t it takes for the current to drop from 90% of its peak value to 10% of its peak value within a single cycle of the aforementioned waveform. Correspondingly, the frequency f′ of the turn-off current fall-edge time is the reciprocal of the turn-off current fall-edge time, 1 / t. When a power module includes multiple power switches, the frequencies of the turn-off current fall-edge times of different power switches in the power module are approximately the same. It can be understood that a large current change rate di / dt is generated when the power switch is turned off. di / dt interacts with the stray inductance L of the current path, generating an induced voltage V = L * di / dt. This induced voltage, combined with the bus voltage, acts on both ends of the power module, creating instantaneous voltage fluctuations and increasing the risk of power module failure. In the high-frequency current component of the ripple current, the frequency of the current that generates the induced voltage V is approximately equal to the frequency f′ of the falling edge of the power switch's turn-off current. Therefore, this implementation method can make the impedance of the second current path to the current at the frequency of the falling edge of the turn-off current lower. The current with frequency f′ can be absorbed by the second capacitor bank through the second current path with lower stray inductance, thereby reducing the fluctuation of the instantaneous voltage at the turn-off of the power module.

[0012] In conjunction with the first aspect, or any of the first to fifth possible implementations of the first aspect, in a sixth possible implementation of the first aspect, the supporting capacitor module includes: a positive busbar connecting all the first terminals; a negative busbar connecting all the second terminals; the two ends of the first capacitor group being connected to the positive busbar and the negative busbar respectively; the two ends of the second capacitor group being connected to the positive busbar and the negative busbar respectively; and the current direction in the positive busbar being opposite to the current direction in the negative busbar. In this implementation, the first current path is a path formed by sequentially connecting the first terminals, the positive busbar, the first capacitor group, the negative busbar, and the second terminals, and the second current path is a path formed by sequentially connecting the first terminals, the positive busbar, the second capacitor group, the negative busbar, and the second terminals. This implementation can reduce the inductance value generated by electromagnetic induction of the positive and negative busbars, thereby reducing the stray inductance of the first current path and the stray inductance of the second current path.

[0013] In conjunction with the sixth possible implementation of the first aspect, in the seventh possible implementation of the first aspect, the positive busbar includes multiple positive busbar layers connected in parallel; the negative busbar includes multiple negative busbar layers connected in parallel; the multiple positive busbar layers and the multiple negative busbar layers are alternately stacked; the first current path passes through the multiple positive busbar layers and the multiple negative busbar layers, and / or the second current path passes through the multiple positive busbar layers and the multiple negative busbar layers; the current direction in the multiple positive busbar layers is opposite to the current direction in the multiple negative busbar layers. This implementation uses multiple positive busbar layers and multiple negative busbar layers to construct the positive busbar and the negative busbar respectively. All positive busbar layers and negative busbar layers participate in the corresponding first current path and / or second current path. When current passes through the first current path and / or the second current path, the current will flow through all positive busbar layers and negative busbar layers, thereby increasing the current carrying capacity of the positive busbar and the negative busbar. Alternating stacking of multiple positive busbar layers and multiple negative busbar layers can reduce the spacing between the positive busbar layer and the adjacent negative busbar layer. At the same time, the opposite current direction in each positive busbar layer and the opposite current direction in each negative busbar layer can reduce the inductance value generated by electromagnetic induction in the adjacent positive busbar layer and negative busbar layer, thereby reducing the stray inductance of the first current path and the stray inductance of the second current path.

[0014] In conjunction with the first aspect, or any of the first to seventh possible implementations of the first aspect, in the eighth possible implementation of the first aspect, the first capacitor bank includes a plurality of capacitors connected in parallel; the plurality of capacitors in the first capacitor bank are uniformly and symmetrically distributed near the power module; and / or the second capacitor bank includes a plurality of capacitors connected in parallel; the plurality of capacitors in the second capacitor bank are uniformly and symmetrically distributed near the power module. The plurality of capacitors connected in parallel helps to increase the equivalent capacitance of the first capacitor bank and / or the second capacitor bank, improving the absorption capability of the first capacitor bank for low-frequency current components and / or the second capacitor bank for high-frequency current components. It is understood that one or more power switches supporting each pair of terminal connections of the capacitor module are packaged in a power device; correspondingly, the power module includes one or more power devices. To achieve a uniform distribution of multiple capacitors in the first and / or second capacitor groups near the power module, one possible implementation is to arrange the multiple capacitors in the first and / or second capacitor groups uniformly along a second direction and having a first midpoint, and to also arrange one or more power devices uniformly along the second direction and having a second midpoint, with the line connecting the first and second midpoints perpendicular to the second direction. This uniform distribution of multiple capacitors in the first and / or second capacitor groups near the power module ensures that the distances from different capacitors in the first and / or second capacitor groups to the power module are relatively consistent, resulting in a more uniform loss rate for each capacitor in the first and / or second capacitor groups.

[0015] In conjunction with the first aspect, or any of the first to eighth possible implementations of the first aspect, in the ninth possible implementation of the first aspect, the supporting capacitor module further includes a PCB board; the positive busbar and the negative busbar are located on the PCB board; the first capacitor group and the second capacitor group are respectively located on two sides of the PCB board. When the positive busbar includes multiple parallel positive busbar layers and the negative busbar includes multiple parallel negative busbar layers, the PCB board can be a multi-layer PCB board, with the conductive layer in each PCB board serving as the positive busbar layer or the negative busbar layer; the PCB board can also be a composite PCB board, using conductive structures such as copper sheets as the positive busbar layer and the negative busbar layer, and the conductive structures such as copper sheets are composited into the PCB board to obtain a composite PCB board. Compared to directly connecting the first capacitor group and the second capacitor group to independent positive and negative busbars, mounting the first capacitor group and the second capacitor group on the PCB board allows the first capacitor group and the second capacitor group to be connected to the positive and negative busbars through conductive vias on the PCB board, thereby reducing the installation difficulty of the first capacitor group and the second capacitor group. Compared to having the first and second capacitor banks located on the same side of the PCB, having the first and second capacitor banks located on opposite sides of the PCB makes it easier to simultaneously shorten the distance between the first and second capacitor banks and the terminals, thereby reducing the overall stray inductance of the supporting capacitor module.

[0016] In conjunction with the first aspect, or any of the first to ninth possible implementations of the first aspect, in the tenth possible implementation of the first aspect, the supporting capacitor module further includes a PCB board; the one or more pairs of terminals and the second capacitor group are respectively located in the same area on both sides of the PCB board. In this implementation, the one or more pairs of terminals and the second capacitor group are separated only by the PCB board, that is, the distance between the one or more pairs of terminals and the second capacitor group is the thickness of the PCB board. The thickness of the PCB board is usually small, thereby effectively reducing the length of the second current path and reducing the stray inductance of the second current path.

[0017] In conjunction with the first aspect, or any of the first to ninth possible implementations of the first aspect, in the eleventh possible implementation of the first aspect, the supporting capacitor module further includes a PCB board; the first terminal and the second terminal in each pair of terminals are respectively located in the same area on both sides of the PCB board. The current directions in the first terminal and the second terminal are opposite. Therefore, the fact that the first terminal and the second terminal are respectively located in the same area on both sides of the PCB board can reduce the inductance value generated by electromagnetic induction of the first terminal and the second terminal, thereby reducing the stray inductance of the first current path and the second current path.

[0018] In a twelfth possible implementation of the first aspect, combining any of the ninth to eleventh possible implementations, the supporting capacitor module further includes a filter component located on the PCB board and connected to the positive busbar and the negative busbar. The filter component needs to be connected to both the positive and negative busbars to achieve a filtering effect. Specifically, the filter component includes at least one of a filter capacitor and a filter core. In conventional solutions, the positive and negative busbars are separate copper busbars, requiring the pins of the filter capacitor and filter core to be soldered onto the copper busbars. However, copper busbars typically do not have mounting positions for the filter capacitor and filter core, making the soldering process difficult. Furthermore, to facilitate soldering, the pins of the filter capacitor and filter core are usually quite long, resulting in poor filtering performance. In this implementation, the positive and negative busbars are set on the PCB board. The connection technology between the PCB board and the filter capacitor and filter core is relatively mature. Through the conductive vias and other structures on the PCB board, the filter capacitor and filter core can be fixed on the PCB board and connected to the positive and negative busbars. The installation process is simple and easy, and the leads of the filter capacitor and filter core do not need to be too long, resulting in good filtering effect.

[0019] In conjunction with the first aspect, or any of the first to twelfth possible implementations of the first aspect, in the thirteenth possible implementation of the first aspect, the first frequency range is 1kHz-20kHz; and the second frequency range is 1MHz-100MHz.

[0020] In a second aspect, a motor controller is provided, comprising: a support capacitor module as described in the first aspect, or any of the first to thirteenth possible implementations of the first aspect; and a power module including a plurality of power switches. The motor controller draws power from an external battery, converts the direct current from the battery into alternating current that meets requirements through the support capacitor module and the power module, and outputs it.

[0021] Thirdly, an electric drive system is provided, comprising: a motor controller as described in the second aspect; and a motor, the input of which is connected to a power module of the motor controller. In this electric drive system, the alternating current output from the power module of the motor controller is used to drive the motor.

[0022] Fourthly, a vehicle is provided, comprising the electric drive system described in the third aspect. Specifically, the output of a motor in the electric drive system is connected to the wheels of the vehicle via a transmission mechanism, thereby driving the vehicle.

[0023] Fifthly, an electronic device is provided, comprising: a supporting capacitor module as described in the first aspect, or any of the first to thirteenth possible implementations of the first aspect. Specifically, the electronic device can be various types of converters, such as traction converters, wind power converters, photovoltaic inverters, high-voltage frequency converters, etc.; the electronic device can also be an uninterruptible power supply (UPS), an emergency power supply (EPS), a static var generator (SVG), an active power filter (APF), etc. Attached Figure Description

[0024] Figure 1 Schematic diagrams of the structure of electronic devices provided for some embodiments of this application;

[0025] Figure 2 Schematic diagrams of the structure of electronic devices provided for some embodiments of this application;

[0026] Figure 3 This application provides a front view structural diagram of a supporting capacitor module for some embodiments;

[0027] Figure 4 Top view of the supporting capacitor module provided for some embodiments of this application;

[0028] Figure 5 A schematic diagram of the first current path in a supporting capacitor module provided for some embodiments of this application;

[0029] Figure 6 A schematic diagram of the second current path in a supporting capacitor module provided for some embodiments of this application;

[0030] Figure 7 A schematic diagram of the second current path in a supporting capacitor module provided for some embodiments of this application;

[0031] Figure 8 This is a schematic diagram of the structure of the supporting capacitor module provided in some embodiments of this application;

[0032] Figure 9 A schematic diagram of the first current path in a supporting capacitor module provided for some embodiments of this application;

[0033] Figure 10 A schematic diagram of the second current path in a supporting capacitor module provided for some embodiments of this application;

[0034] Figure 11 This is a schematic diagram of the structure of the supporting capacitor module provided in some embodiments of this application;

[0035] Figure 12 This is a schematic diagram of the structure of the supporting capacitor module provided in some embodiments of this application;

[0036] Figure 13 This is a schematic diagram of the structure of a supporting capacitor module provided in some embodiments of this application.

[0037] Explanation of reference numerals in the attached figures:

[0038] 10 - Support capacitor module;

[0039] 101 - Terminal block; 102 - Positive busbar; 103 - Negative busbar; 104 - First capacitor bank; 105 - Second capacitor bank; 106 - PCB board; 107 - Filter assembly; 108 - First current path; 109 - Second current path;

[0040] 1011 - First terminal; 1012 - Second terminal; 1013 - Third terminal; 1014 - Fourth terminal; 1021 - Positive busbar layer; 1031 - Negative busbar layer; 1041 - First midpoint; 1051 - First midpoint; 1061 - Insulating layer; 1062 - Conductive via; 1071 - Filter capacitor; 1072 - Filter core;

[0041] 20-Power Module;

[0042] 201-Power Devices;

[0043] 2011 - Second Midpoint;

[0044] 30 - Motor;

[0045] 40-battery;

[0046] 50 - Motor controller;

[0047] 60 - Connecting reactor;

[0048] 70-Power Grid;

[0049] 80-Static Var Generator. Detailed Implementation

[0050] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0051] In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. It should be noted that the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone.

[0052] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0053] In the description of this application, it should be understood that the terms "upper", "lower", "side", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the installation orientation or positional relationship, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0054] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0055] It should also be noted that the accompanying drawings in this application are only used to illustrate the position, connection, and composition of the various parts or components. Unless otherwise specified, the drawings are not used to illustrate the size relationships of the various parts or components.

[0056] This application provides a supporting capacitor module, a motor controller, an electric drive system, an automotive component, and electronic equipment. The supporting capacitor module can be applied to electronic equipment and related modules and functional components with power conversion capabilities. Specifically, the electronic equipment can be various types of power converters, such as traction power converters, wind power converters, photovoltaic inverters, high-voltage frequency converters, etc.; the electronic equipment can also be uninterruptible power supplies (UPS), emergency power supplies (EPS), static var generators (SVG), active power filters (APF), motor controllers, etc. The electronic equipment includes a supporting capacitor module, which provides voltage support, energy storage, and harmonic current absorption.

[0057] Please refer to Figure 1 Taking a motor controller 50 as an example, the motor controller 50 includes a support capacitor module 10 and a power module 20. The power module 20 includes multiple power switches, which form a bridge circuit. The motor controller 50 converts the DC power output from the battery 40 into AC power to drive the motor 30 by controlling the on / off states of the multiple power switches. The support capacitor module 10 absorbs the ripple current generated by the frequent operation of the power switches and smooths the voltage.

[0058] Please refer to Figure 2 Taking a static var generator (SVA) 80 as an example, the SVA 80 includes a connecting reactor 60, a power module 20, and a supporting capacitor module 10. The power module 20 includes multiple power switches, which form a bridge circuit. The DC side of the SVA 80 uses the supporting capacitor module 10 as an energy storage element, while the AC side is connected in parallel with the power grid 70 through the connecting reactor 60. By changing the amplitude and phase of the AC side current or the output voltage of the control device, the SVA 80 can be adjusted to generate or absorb the target reactive power, thereby achieving dynamic reactive power compensation.

[0059] Please refer to Figure 3 and Figure 4 Some embodiments of this application provide a supporting capacitor module 10. The supporting capacitor module 10 includes one or more pairs of terminals 101, a positive busbar 102, a negative busbar 103, a first capacitor group 104, and a second capacitor group 105.

[0060] Each pair of terminals 101 of the supporting capacitor module 10 includes a first terminal 1011 and a second terminal 1012. When the supporting capacitor module 10 is connected to the power module 20, the first terminal 1011 and the second terminal 1012 of each pair of terminals 101 are connected to the power module 20.

[0061] It is important to note that Figure 3 and Figure 4 This is a simplified structural diagram of the supporting capacitor module 10 in this embodiment, wherein, Figure 3 This is a front view. Figure 4 This is a top view. Figure 3 and Figure 4 This is not an actual product image supporting capacitor module 10. (In order to...) Figure 3 The first terminal 1011 and the second terminal 1012 are clearly shown simultaneously, as well as the current path, for easy illustration later. Figure 3 The first terminal 1011 and the second terminal 1012 in the capacitor module 10 have different lengths and are misaligned. It is understood that the first terminal 1011 and the second terminal 1012 in the actual supporting capacitor module 10 can have the same length (e.g., ...). Figure 4 (as shown) and in Figure 3 They overlap in perspective.

[0062] The power module 20 includes multiple power switches. Optionally, the power module 20 may include at least one of power switches such as silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs) and insulated-gate bipolar transistors (IGBTs). It is understood that the first terminal 1011 and the second terminal 1012 in each pair of terminals 101 may be connected to the source and drain of the same power switch, respectively, or they may be connected to the source of one power switch and the drain of another power switch, respectively.

[0063] It should be noted that the number of terminal pairs in the supporting capacitor module 10, the number of power switches in the power module 20, and the corresponding connection relationship between one or more pairs of terminals 101 and multiple power switches can all be adjusted according to the specific bridge circuit structure and actual needs. For example, when the bridge circuit structure is a three-phase full-bridge circuit structure, as an optional implementation, such as... Figure 4 As shown, the supporting capacitor module 10 can have three pairs of terminals 101, each corresponding to one of the three phases. Two power switches are connected between each pair of terminals 101: an upper bridge arm power switch and a lower bridge arm power switch. Specifically, the first terminal 1011 is connected to the source of the upper bridge arm power switch, the second terminal 1012 is connected to the drain of the lower bridge arm power switch, and the drain of the upper bridge arm power switch is connected to the source of the lower bridge arm power switch. Figure 4 As shown, the two power switches between each pair of terminals 101 can be packaged into a power device 201, and the three power devices 201 can be connected to the three pairs of terminals 101 by means of welding or other methods, thereby realizing the rapid installation of the power module 20 and the supporting capacitor module 10.

[0064] The positive busbar 102 is connected to the first terminal 1011 in each pair of terminals 101, and the negative busbar 103 is connected to the second terminal 1012 in each pair of terminals 101.

[0065] Optionally, the positive busbar 102 and the negative busbar 103 may have the same structure and / or material. Specifically, the material of the positive busbar 102 and the negative busbar 103 may be copper.

[0066] Optionally, the positive busbar 102 and the negative busbar 103 can be components connected as a single unit by an insulating material, for example, such as... Figure 3 As shown, the positive busbar 102 and the negative busbar 103 can be different layers of copper foil conductive layers in the same PCB board 106, and an insulating layer 1061 made of materials such as resin and glass fiber separates the positive busbar 102 and the negative busbar 103. In addition, the PCB board 106 can be a composite PCB board: using conductive structures such as copper sheets as the positive busbar 102 and the negative busbar 103, the positive busbar 102 and the negative busbar 103 are composited into the PCB board 106 to obtain the composite PCB board.

[0067] Optionally, the positive busbar 102 and the negative busbar 103 can be two independent, separate components. For example, both the positive busbar 102 and the negative busbar 103 are strip-shaped copper sheets, which are detachably fixed inside the package housing supporting the capacitor module 10. The first capacitor group 104 and the second capacitor group 105 are connected to the two strip-shaped copper sheets through pins, wires, or other structures.

[0068] Optionally, the positive busbar 102 and the first terminal 1011, the negative busbar 103 and the second terminal 1012 can be connected by welding, bolting, or other methods. Figure 3 As shown, when the positive busbar 102 and the negative busbar 103 are located in the PCB board 106, the first terminal 1011 and the second terminal 1012 can be connected to the positive busbar 102 and the negative busbar 103 by soldering to the pads or conductive vias 1062 of the PCB board 106. It should be noted that when the positive busbar 102 and the negative busbar 103 are located in the same composite PCB board, the first terminal 1011 and the second terminal 1012 can also be composited into this composite PCB board and connected to the positive busbar 102 and the negative busbar 103.

[0069] Optionally, the positive busbar 102 and the first terminal 1011 can be an integral structure, and the negative busbar 103 and the second terminal 1012 can be an integral structure. In this case, the first terminal 1011 can be integrally connected to one end of the positive busbar 102, and the second terminal 1012 can be integrally connected to one end of the negative busbar 103.

[0070] The first capacitor bank 104 includes one or more capacitors, and the second capacitor bank 105 includes one or more capacitors. This embodiment does not limit the number of capacitors included in the first capacitor bank 104 and the second capacitor bank 105; for example... Figure 4The first capacitor bank 104 may include six capacitors, and the second capacitor bank 105 may include two capacitors. When the first capacitor bank 104 includes multiple capacitors, these capacitors may be connected in series, in parallel, or some capacitors may be connected in series and some in parallel. When the second capacitor bank 105 includes multiple capacitors, these capacitors may be connected in series, in parallel, or some capacitors may be connected in series and some in parallel.

[0071] The first capacitor bank 104 and the second capacitor bank 105 can be connected to the positive busbar 102 and the negative busbar 103 by means of welding, bolting, or other methods. Figure 3 For example, the first capacitor group 104 and the second capacitor group 105 can be connected to the positive busbar 102 and the negative busbar 103 through conductive vias 1062 soldered in the PCB board 106.

[0072] Please refer to Figure 5 and Figure 6 The first capacitor bank 104 and the second capacitor bank 105 are connected in parallel between the positive busbar 102 and the negative busbar 103, thus obtaining two paths for the turn-off current of the power module 20: a first current path 108 and a second current path 109. The first current path 108 is a path formed by sequentially connecting the first terminal 1011, the positive busbar 102, the first capacitor bank 104, the negative busbar 103, and the second terminal 1012. The second current path 109 is a path formed by sequentially connecting the first terminal 1011, the positive busbar 102, the second capacitor bank 105, the negative busbar 103, and the second terminal 1012. It can be understood that the first current path 108 and the second current path 109 not only include the aforementioned components, but also the connection structure between adjacent components; the connection structure can be wires, solder joints, bolts, conductive vias 1062, etc.

[0073] The impedances |Z1| of the first current path 108 and |Z2| of the second current path 109 can be calculated using the following formulas.

[0074]

[0075] Where R1 is the equivalent resistance of the first current path 108, C1 is the equivalent capacitance of the first current path 108, and L1 is the stray inductance of the first current path 108; R2 is the equivalent resistance of the second current path 109, C2 is the equivalent capacitance of the second current path 109, L2 is the stray inductance of the second current path 109, and f is the frequency.

[0076] When the frequency f is in the first frequency range [f1, f2], |Z1| < |Z2|, that is, the impedance of the first current path 108 is less than the impedance of the second current path 109.

[0077] When the frequency f is in the second frequency range [f3, f4], |Z1|>|Z2|, that is, the impedance of the first current path 108 is greater than the impedance of the second current path 109.

[0078] In this frequency range, the first frequency interval [f1, f2] is smaller than the second frequency interval [f3, f4], meaning the maximum value f2 in the first frequency interval [f1, f2] is smaller than the minimum value f3 in the second frequency interval [f3, f4]. The first frequency interval [f1, f2] is the low-frequency range, and the second frequency interval [f3, f4] is the high-frequency range. Optionally, the first frequency interval [f1, f2] is 1kHz-20kHz, and the second frequency interval [f3, f4] is 1MHz-100MHz.

[0079] The ripple current generated when the power switch is turned off contains both low-frequency and high-frequency current components. Since the impedance of the first current path 108 is lower in the low-frequency range, and the impedance of the second current path 109 is lower in the high-frequency range, the low-frequency current component mainly passes through the first current path 108 and is absorbed by the first capacitor bank 104, while the high-frequency current component mainly passes through the second current path 109 and is absorbed by the second capacitor bank 105. The stray inductance L1 of the first current path 108 is greater than the stray inductance L2 of the second current path 109. The instantaneous voltage spike during power switch turn-off is determined by both the rate of change of current and the stray inductance of the current path. The low-frequency current component has a smaller impact on the instantaneous voltage fluctuation, while the high-frequency current component has a larger impact. The larger the stray inductance of the current path, the greater the instantaneous voltage fluctuation during power switch turn-off. Therefore, compared with the existing solution that uses a capacitor bank to absorb both low-frequency and high-frequency current components, the supporting capacitor module 10 in this embodiment is designed with a second current path 109 that has lower high-frequency impedance and smaller stray inductance. This makes the instantaneous voltage fluctuation generated by the high-frequency current component during the process of passing through the second current path 109 and being absorbed by the second capacitor bank 105 smaller, which can effectively reduce the turn-off voltage spike.

[0080] Optionally, the current direction in the positive busbar 102 is opposite to the current direction in the negative busbar 103. Please refer to... Figure 5 The current direction of the first current path 108 in the positive busbar 102 is the positive X-axis direction, and the current direction of its path in the negative busbar 103 is the negative X-axis direction. Please refer to... Figure 6 The current direction of the second current path 109 in the positive busbar 102 is in the positive X-axis direction, and the current direction of the second current path 109 in the negative busbar 103 is in the negative X-axis direction. This embodiment can reduce the inductance value generated by electromagnetic induction in the positive busbar 102 and the negative busbar 103, thereby reducing the stray inductance L1 of the first current path 108 and the stray inductance L2 of the second current path 109.

[0081] In some implementations, the resonant frequency f of the first current path 108 01 Located within the first frequency range [f1, f2], the resonant frequency f of the second current path 109 is... 02 It is located in the second frequency range [f3,f4].

[0082] The resonant frequency f of the first current path 108 01 It can be calculated using the equivalent capacitance C1 and the stray inductance L1 of the first current path 108.

[0083]

[0084] The resonant frequency f of the second current path 109 02 It can be calculated using the equivalent capacitance C2 of the second current path 109 and the stray inductance L2 of the second current path 109.

[0085]

[0086] In this embodiment, the resonant frequency f of the first current path 108 01 If the first current path 108 is located within the first frequency range [f1, f2], then the impedance |Z1| of the first current path 108 has a minimum value R1 within the first frequency range [f1, f2]; the resonant frequency f of the second current path 109 is... 02 Located within the second frequency range [f3, f4], the impedance |Z2| of the second current path 109 has a minimum value R2 within the second frequency range [f3, f4]. This makes it easier to achieve |Z1| < |Z2| when the frequency f is in the first frequency range [f1, f2], and |Z1| > |Z2| when the frequency f is in the second frequency range [f3, f4]. Specifically, by designing and testing the equivalent capacitance C1 of the first current path 108, the equivalent capacitance C2 of the second current path 109, the stray inductance L1 of the first current path 108, and the stray inductance L2 of the second current path 109, the resonant frequency f of the first current path 108 can be controlled while ensuring that the stray inductance L1 of the first current path 108 is greater than the stray inductance L2 of the second current path 109. 01 Located within the first frequency range [f1, f2], the resonant frequency f of the second current path 109 is... 02 It is located in the second frequency range [f3,f4].

[0087] In some implementations, when the frequency f is in the first frequency range [f1, f2], the impedance |Z3| of the first capacitor group 104 is less than the impedance |Z4| of the second capacitor group 105; when the frequency f is in the second frequency range [f3, f4], the impedance |Z3| of the first capacitor group 104 is greater than the impedance |Z4| of the second capacitor group 105.

[0088] The impedances |Z3| of the first capacitor bank 104 and |Z4| of the second capacitor bank 105 can be calculated using the following formulas.

[0089]

[0090] Where R3 is the equivalent series resistance of the first capacitor group 104, C3 is the equivalent capacitance of the first capacitor group 104, and L3 is the equivalent series inductance of the first capacitor group 104; R4 is the equivalent series resistance of the second capacitor group 105, C4 is the equivalent capacitance of the second capacitor group 105, L4 is the equivalent series inductance of the second capacitor group 105, and f is the frequency.

[0091] It can be understood that the first current path 108 mainly includes the first terminal 1011, the positive busbar 102, the first capacitor bank 104, the negative busbar 103, and the second terminal 1012. The second current path 109 mainly includes the first terminal 1011, the positive busbar 102, the second capacitor bank 105, the negative busbar 103, and the second terminal 1012. Since the impedances of the first terminal 1011, the positive busbar 102, the negative busbar 103, and the second terminal 1012 are relatively low, the impedances |Z1| of the first current path 108 and |Z2| of the second current path 109 are mainly determined by the impedances |Z3| of the first capacitor bank 104 and |Z4| of the second capacitor bank 105, respectively. Therefore, by controlling the impedance |Z3| of the first capacitor group 104 and the impedance |Z4| of the second capacitor group 105 to satisfy the aforementioned relationship, this embodiment can more easily achieve that when the frequency f is in the first frequency range [f1,f2], |Z1|<|Z2|, and when the frequency f is in the second frequency range [f3,f4], |Z1|>|Z2|.

[0092] In some embodiments, the equivalent capacitance C3 of the first capacitor bank 104 is greater than the equivalent capacitance C4 of the second capacitor bank 105. Since the low-frequency current component is greater than the high-frequency current component in the ripple current generated when the power switch is turned off, this implementation provides a first capacitor bank 104 with a larger capacitance value to adequately absorb the low-frequency current component. Furthermore, a larger capacitance value typically results in a larger equivalent series inductance. This embodiment provides a second capacitor bank 105 with a smaller capacitance value, which reduces the equivalent series inductance of the second capacitor bank 105, making it easier to control the stray inductance L2 of the second current path 109 to be less than the stray inductance L1 of the first current path 108.

[0093] In some embodiments, the first capacitor bank 104 includes at least one of film capacitors and electrolytic capacitors. Film capacitors and electrolytic capacitors typically have large capacitance values, which is beneficial for absorbing a large amount of low-frequency current components. Although the equivalent series inductance of film capacitors and electrolytic capacitors is typically large, it is mainly used to absorb low-frequency current components, so it will not cause large fluctuations in the instantaneous voltage during the turn-off of high-frequency power switches.

[0094] In some embodiments, the second capacitor bank 105 includes at least one of ceramic capacitors and film capacitors. Ceramic capacitors have a smaller equivalent series inductance, which can reduce the fluctuation of the turn-off instantaneous voltage of the high-frequency power switch caused by high-frequency current components. Although the capacitance of ceramic capacitors is typically small, the high-frequency current component is smaller, thus ceramic capacitors can meet the requirement of absorbing high-frequency current components. The second capacitor bank 105 can also use film capacitors; it is understood that the capacitance of the film capacitors in the second capacitor bank 105 is smaller than the capacitance of the film capacitors in the first capacitor bank 104. The capacitance of the second capacitor bank 105 can be increased and stray inductance reduced by connecting multiple film capacitors in parallel.

[0095] In some embodiments, the equivalent series inductance L3 of the first capacitor bank 104 is greater than the equivalent series inductance L4 of the second capacitor bank 105. The stray inductance L1 of the first current path 108 mainly includes two parts: the equivalent series inductance L3 of the first capacitor bank 104 and the stray inductance L5 of the lines of the first current path 108 (i.e., the parts of the positive busbar 102 and the negative busbar 103 located in the first current path 108, and the connection between the first terminal 1011, the positive busbar 102, the first capacitor bank 104, the negative busbar 103, the second terminal 1012, etc.), that is, L1 = L3 + L5. Similarly, the stray inductance L2 of the second current path 109 mainly consists of two parts: the equivalent series inductance L4 of the second capacitor bank 105 and the stray inductance L6 of the lines in the second current path 109 (i.e., the parts of the positive busbar 102 and negative busbar 103 located in the second current path 109, and the connections between the first terminal 1011, the positive busbar 102, the second capacitor bank 105, the negative busbar 103, the second terminal 1012, etc.), i.e., L2 = L4 + L6. This embodiment, by designing and adjusting the equivalent series inductance L3 of the first capacitor bank 104 to be greater than the equivalent series inductance L4 of the second capacitor bank 105, can more easily achieve the stray inductance L1 of the first current path 108 being greater than the stray inductance L2 of the second current path 109.

[0096] In some implementation methods, please refer to Figure 5 and Figure 6 , Figure 5 The multiple dashed arrows connected end to end in the middle represent the flow paths of the low-frequency current components, corresponding to the first current path 108. Figure 6 The multiple dashed arrows connected end-to-end represent the flow paths of high-frequency current components, corresponding to the second current path 109. The length of the first current path 108 is greater than the length of the second current path 109. The longer the first current path 108, the greater its stray inductance L5. The shorter the second current path 109, the smaller its stray inductance L6. This implementation makes it easier to ensure that the stray inductance L1 of the first current path 108 is greater than the stray inductance L2 of the second current path 109.

[0097] It is understood that only a portion of the positive busbar 102 located between the first capacitor group 104 and the first terminal 1011, and a portion of the negative busbar 103 located between the first capacitor group 104 and the second terminal 1012, belong to the first current path 108; only a portion of the positive busbar 102 located between the second capacitor group 105 and the first terminal 1011, and a portion of the negative busbar 103 located between the second capacitor group 105 and the second terminal 1012, belong to the second current path 109. Therefore, the lengths of the first current path 108 and the second current path 109 can be adjusted by controlling the mounting positions of the first capacitor group 104 and the second capacitor group 105 on the positive busbar 102 and the negative busbar 103. Optionally, as... Figure 5 and Figure 6 As shown, relative to the mounting positions of the second capacitor bank 105 on the positive busbar 102 and negative busbar 103, the mounting positions of the first capacitor bank 104 on the positive busbar 102 and negative busbar 103 can be further away from the first terminal 1011 and the second terminal 1012, thereby making the length of the first current path 108 greater than the length of the second current path 109. Optionally, please refer to... Figure 5 and Figure 7 In contrast Figure 5 , Figure 7 The position of the second capacitor group 105 was changed, while the position of the first capacitor group 104 remained essentially unchanged. Therefore, Figure 7 The length of the first current path can be referenced Figure 5 The length of the first current path 108 in the diagram. For example... Figure 7 As shown, relative to the mounting positions of the second capacitor bank 105 on the positive busbar 102 and the negative busbar 103, the mounting positions of the first capacitor bank 104 on the positive busbar 102 and the negative busbar 103 can be the same or even slightly away from the first terminal 1011 and the second terminal 1012. However, the current path length in the first capacitor bank 104 is greater than the current path length in the second capacitor bank 105 (for example, the volume of the first capacitor bank 104 is greater than the volume of the second capacitor bank 105), thereby making the length of the entire first current path 108 greater than the length of the entire second current path 109.

[0098] In some embodiments, the magnetic coupling coefficient of the second current path 109 is greater than that of the first current path 108. The magnetic coupling coefficient of the first current path 108 is determined by factors such as the current direction, spacing, and overlapping area size of different segments of the first current path 108. The smaller the magnetic coupling coefficient of the first current path 108, the larger the stray inductance L5 of the line of the first current path 108. The magnetic coupling coefficient of the second current path 109 is determined by factors such as the current direction, spacing, and overlapping area size of different segments of the second current path 109. The larger the magnetic coupling coefficient of the second current path 109, the smaller the stray inductance L6 of the line of the second current path 109. By designing the current direction, spacing, and overlapping area size of the first current path 108 and the second current path 109 such that the magnetic coupling coefficient of the second current path 109 is greater than that of the first current path 108, it is easier to achieve a stray inductance L1 of the first current path 108 greater than that of the second current path 109.

[0099] In some embodiments, the resonant frequency f of the second current path 109 02The ratio of the frequency f′ of the falling edge of the turn-off current of each power switch in the power module 20 to the frequency f′ of the turning-off current of each power switch in the power module 20 is 0.5-1.5; or the ratio of the resonant frequency of the second current path 109 to the frequency f′ of the falling edge of the turn-off current of each power switch in the power module 20 is 0.8-1.2; or the ratio of the resonant frequency of the second current path 109 to the frequency f′ of the falling edge of the turn-off current of each power switch in the power module 20 is 0.9-1.1. During operation, each power switch in the power module 20 needs to be periodically turned on and off. When the power switch is turned on, the current rises rapidly from 0 to its peak value; when the power switch is turned off, the current drops rapidly from its peak value to 0. Accordingly, the waveform of the current of the power switch over time is a periodic trapezoidal wave. The falling edge time of the turn-off current of the power switch refers to the time t taken for the current to drop from 90% of the peak value to 10% of the peak value within a single period of the aforementioned waveform. Correspondingly, the frequency f′ of the falling edge of the turn-off current of the power switch is the reciprocal of the falling edge time of the turn-off current of the power switch, 1 / t. When the power module 20 includes multiple power switches, the falling edges of the turn-off currents of different power switches in the power module 20 have approximately the same frequency. It is understood that a large current change rate di / dt is generated when the power switch is turned off. The interaction between di / dt and the stray inductance L of the current path generates an induced voltage V = L * di / dt. This induced voltage, combined with the bus voltage, acts on both ends of the power module, resulting in instantaneous voltage fluctuations and increasing the risk of power module failure. In the high-frequency current component of the ripple current, the frequency of the current generating the induced voltage V is approximately equal to the frequency f′ of the falling edge of the turn-off current of the power switch. Therefore, this implementation allows the second current path 109 to have a lower impedance to currents with frequency f′. Currents with frequency f′ can be absorbed by the second capacitor bank 105 through the second current path 109, which has lower stray inductance, thereby reducing the fluctuation of the instantaneous turn-off voltage of the power module 20.

[0100] In some implementation methods, please refer to Figure 8 The positive busbar 102 includes multiple positive busbar layers 1021 connected in parallel, and the multiple positive busbar layers 1021 are connected to each other through conductive vias 1062; the negative busbar 103 includes multiple negative busbar layers 1031 connected in parallel, and the multiple negative busbar layers 1031 are connected to each other through conductive vias 1062; the multiple positive busbar layers 1021 and the multiple negative busbar layers 1031 are connected along a first direction (e.g., Figure 8 The Z-axis (negative direction) is arranged in alternating layers. For example... Figure 9 and Figure 10As shown, the first current path 108 passes through the plurality of positive busbar layers 1021 and the plurality of negative busbar layers 1031, and the second current path 109 passes through the plurality of positive busbar layers 1021 and the plurality of negative busbar layers 1031; the current direction in the plurality of positive busbar layers 1021 is opposite to the current direction in the plurality of negative busbar layers 1031. In this embodiment, a positive busbar 102 is constructed using a plurality of positive busbar layers 1021, and a negative busbar 103 is constructed using a plurality of negative busbar layers 1031. All positive busbar layers 1021 and negative busbar layers 1031 participate in the corresponding first current path 108 and / or second current path 109: when current flows through the first current path 108 and / or the second current path 109, the current will flow through all positive busbar layers 1021 and negative busbar layers 1031, thereby increasing the current carrying capacity of the positive busbar 102 and the negative busbar 103. The alternating stacking of multiple positive busbar layers 1021 and multiple negative busbar layers 1031 can reduce the spacing between the positive busbar layer 1021 and the adjacent negative busbar layer 1031. At the same time, the current direction in each positive busbar layer 1021 is opposite to the current direction in each negative busbar layer 1031, which can reduce the inductance value generated by electromagnetic induction in the adjacent positive busbar layer 1021 and negative busbar layer 1031, thereby reducing the stray inductance of the first current path 108 and the second current path 109.

[0101] Optionally, positive busbar 102 and negative busbar 103 together form multiple busbar stacks, each busbar stack including a positive busbar layer 1021 and a first direction (e.g. Figure 8 The negative bus layer 1031 is adjacent to the positive bus layer 1021 in the negative Z-axis direction. Each positive bus layer 1021 forms a first sub-current path to the negative bus layer 1031 in the same bus stack via a first capacitor bank 104, and the first circuit path includes all first sub-current paths. Each positive bus layer 1021 forms a second sub-current path to the negative bus layer 1031 in the same bus stack via a second capacitor bank 105, and the second circuit path includes all second sub-current paths.

[0102] Optionally, such as Figure 8As shown, multiple positive busbar layers 1021 and multiple negative busbar layers 1031 can be connected in the PCB board 106 via an insulating layer 1061. For example, the multiple positive busbar layers 1021 and multiple negative busbar layers 1031 can be copper foil conductive layers of different layers in a multilayer PCB board 106, and the insulating layer 1061, made of materials such as resin and glass fiber, separates adjacent positive busbar layers 1021 and negative busbar layers 1031. Furthermore, the PCB board 106 can be a composite PCB board: using conductive structures such as copper sheets as positive busbar layers 1021 and / or negative busbar layers 1031, multiple positive busbar layers 1021 and / or multiple negative busbar layers 1031 are stacked and composited in the PCB board 106 to obtain this composite PCB board. In this composite PCB board, adjacent copper sheets are separated by the insulating layer 1061. The first capacitor group 104 and / or the second capacitor group 105 are connected to each positive bus layer 1021 and each negative bus layer 1031 through structures such as conductive vias 1062, so that the first current path 108 can pass through multiple positive bus layers 1021 and multiple negative bus layers 1031, and / or the second current path 109 can pass through multiple positive bus layers 1021 and multiple negative bus layers 1031.

[0103] Optionally, such as Figure 8 As shown, one electrode of each capacitor in the first capacitor group 104 and the second capacitor group 105 is connected to multiple positive bus layers 1021 through a conductive via 1062, and the other electrode is connected to multiple negative bus layers 1031 through another conductive via 1062. This embodiment requires fewer conductive vias 1062, the structure of the PCB board 106 is simple, easy to process and install, and the first current path 108 and the second current path 109 are simple, making it easy to design and plan the first current path 108 and the second current path 109 to reduce stray inductance.

[0104] Optionally, each positive busbar layer 1021 and / or negative busbar layer 1031 can be an independent, separate component. For example, each positive busbar layer 1021 and / or negative busbar layer 1031 can be a strip of copper sheet, detachably fixed within the package housing supporting the capacitor module 10. The first capacitor group 104 and the second capacitor group 105 are connected to each strip of copper sheet via pins, wires, or other structures, so that the first current path 108 passes through multiple positive busbar layers 1021 and multiple negative busbar layers 1031, and the second current path 109 passes through multiple positive busbar layers 1021 and multiple negative busbar layers 1031.

[0105] In some implementation methods, please refer to Figure 4The first capacitor bank 104 includes multiple capacitors connected in parallel; the multiple capacitors in the first capacitor bank 104 are evenly distributed near the power module 20; and / or the second capacitor bank 105 includes multiple capacitors connected in parallel; the multiple capacitors in the second capacitor bank 105 are evenly distributed near the power module 20. Multiple capacitors connected in parallel help increase the equivalent capacitance of the first capacitor bank 104 and / or the second capacitor bank 105, improving the absorption capability of the first capacitor bank 104 for low-frequency current components and / or the second capacitor bank 105 for high-frequency current components. It can be understood that, as Figure 4 As shown, one or more power switches connected to each pair of terminals 101 of the supporting capacitor module 10 are encapsulated in a power device 201. Accordingly, the power module 20 includes one or more power devices 201. To achieve a uniform distribution of multiple capacitors in the first capacitor group 104 and / or the second capacitor group 105 near the power module 20, as... Figure 4 As shown, one optional implementation is: multiple capacitors in the first capacitor group 104 and / or the second capacitor group 105 are aligned along a second direction (e.g., ...). Figure 4 The power modules 201 and 1021 are uniformly arranged along the Y-axis and have a first midpoint 1041 and / or a first midpoint 1051. One or more power devices 201 are also uniformly arranged along the second direction and have a second midpoint 2011. The line connecting the first midpoint 1041 and the second midpoint 2011 and / or the line connecting the first midpoint 1051 and the second midpoint 2011 is perpendicular to the second direction. The second direction may differ from the first direction in which the positive busbar layer 1021 and the negative busbar layer 1031 are stacked. This embodiment allows the distances from different capacitors in the first capacitor group 104 and / or the second capacitor group 105 to the power module 20 to be more consistent, thereby resulting in a more uniform loss degree for each capacitor in the first capacitor group 104 and / or the second capacitor group 105.

[0106] In some implementations, such as Figure 8As shown, positive busbar 102 and negative busbar 103 are located in PCB board 106. The first capacitor group 104 and the second capacitor group 105 are located on opposite sides of PCB board 106. PCB board 106 can be a multilayer PCB board, with the conductive layer in each PCB board serving as either positive busbar layer 1021 or negative busbar layer 1031; PCB board 106 can also be a composite PCB board, using conductive structures such as copper sheets as positive busbar layer 1021 and negative busbar layer 1031, and combining the conductive structures such as copper sheets into PCB board 106 to obtain a composite PCB board. Compared to directly connecting the first capacitor bank 104 and the second capacitor bank 105 to the independent positive busbar 102 and negative busbar 103, fixing the first capacitor bank 104 and the second capacitor bank 105 onto the PCB board 106 via wave soldering or other methods allows them to be connected to the positive busbar 102 and negative busbar 103 through conductive vias 1062 on the PCB board 106, thus reducing the installation difficulty of the first capacitor bank 104 and the second capacitor bank 105. It is understandable that if the first capacitor bank 104 and the second capacitor bank 105 are located on the same side of the PCB board 106, the dimensions of the first capacitor bank 104 and the second capacitor bank 105, as well as the distance between them, need to be considered when arranging their positions, making it difficult to shorten the distance from the first capacitor bank 104 and the second capacitor bank 105 to the terminals. In this embodiment, the first capacitor group 104 and the second capacitor group 105 are located on both sides of the PCB board 106, respectively. There is no need to consider the size of the first capacitor group 104 and the second capacitor group 105 and the distance between them. It is easier to shorten the distance from the first capacitor group 104 and the second capacitor group 105 to the first terminal 1011 and the second terminal 1012 at the same time, thereby reducing the overall stray inductance of the supporting capacitor module 10.

[0107] In some implementations, such as Figure 11 As shown, the first terminal 1011 and the second terminal 1012 of a pair of terminals 101 are located in the same area on both sides of the PCB board 106, that is, the area of ​​the first terminal 1011 on one side of the PCB board 106 completely or partially overlaps with the area of ​​the second terminal 1012 on the other side of the PCB board 106. The current directions in the first terminal 1011 and the second terminal 1012 are opposite. Therefore, the fact that the first terminal 1011 and the second terminal 1012 are located in the same area on both sides of the PCB board 106 can reduce the inductance value generated by the electromagnetic induction of the first terminal 1011 and the second terminal 1012, thereby reducing the stray inductance of the first current path 108 and the second current path 109.

[0108] In some implementations, such as Figure 12As shown, one or more pairs of terminals 101 and the second capacitor group 105 are located in the same area on both sides of the PCB board 106, that is, the area of ​​one or more pairs of terminals 101 on one side of the PCB board 106 completely or partially overlaps with the area of ​​the second capacitor group 105 on the other side of the PCB board 106. In this implementation, the one or more pairs of terminals 101 and the second capacitor group 105 are separated only by the PCB board 106, that is, the distance between the one or more pairs of terminals 101 and the second capacitor group 105 is the thickness of the PCB board 106. The thickness of the PCB board 106 is usually small, which can effectively reduce the length of the second current path 109 and reduce the stray inductance of the second current path 109.

[0109] Optionally, such as Figure 12 As shown, at least one capacitor in the second capacitor group 105 has one electrode connected to multiple positive bus layers 1021 and a first terminal 1011 through a conductive via 1062, and its other electrode connected to multiple negative bus layers 1031 and a second terminal 1012 through another conductive via 1062. Specifically, at least one capacitor in the second capacitor group 105 and the first terminal 1011 (or the second terminal 1012) of a pair of terminals 101 can be wave soldered to both ends of the same conductive via 1062, thereby reducing the number of conductive vias 1062 required, making the structure of the PCB board 106 simple, easy to process and install, and ensuring that the length of the second current path 109 is minimized, reducing the stray inductance of the second current path 109.

[0110] In some implementations, such as Figure 13As shown, the supporting capacitor module 10 also includes a filter component 107. The filter component 107 is located on the PCB board 106 where the positive busbar 102 and the negative busbar 103 are located, and the filter component 107 connects the positive busbar 102 and the negative busbar 103 to achieve a filtering effect. Specifically, the filter component 107 includes at least one of a filter capacitor 1071 and a filter core 1072. Optionally, the filter capacitor 1071 includes an X capacitor and a Y capacitor. Optionally, the filter core 1072 includes a differential-mode inductor and a common-mode inductor. In some implementations, the differential-mode inductor and the common-mode inductor can be the same inductor. In conventional solutions, the positive busbar 102 and the negative busbar 103 are separate copper busbars, requiring the pins of the filter capacitor 1071 to be soldered onto the copper busbars. However, copper busbars usually do not have mounting positions for the filter capacitor 1071, making the process of soldering the filter capacitor 1071 onto the copper busbars difficult. In addition, to facilitate soldering, the pins of the filter capacitor 1071 are usually long, resulting in poor filtering effect. In this embodiment, the positive busbar 102 and negative busbar 103 are disposed on the PCB board 106. The connection technology between the PCB board 106 and the filter capacitor 1071 is relatively mature. Through the conductive vias 1062, pads, and other structures on the PCB board 106, the filter capacitor 1071 can be fixed on the PCB board 106 and connected to the positive busbar 102 and negative busbar 103. The installation process is simple and easy, and the leads of the filter capacitor 1071 do not need to be too long, resulting in good filtering effect. The filter core 1072 also has the problem of being difficult to install on the copper busbar. However, when the filter core 1072 is installed on the PCB board 106, the traces of the PCB board 106 can be used as windings, and the upper and lower cores can be glued to the PCB board 106. The installation process is simple and easy.

[0111] like Figure 1 As shown, some embodiments of this application provide a motor controller 50. The motor controller 50 includes a support capacitor module 10 and a power module 20, wherein the support capacitor module 10 can be any of the support capacitor modules described in the foregoing embodiments, and the power module 20 includes a plurality of power switches. Optionally, the power module 20 may include at least one of power switches such as SiC MOSFETs and IGBTs. Optionally, as... Figure 13 As shown, the supporting capacitor module 10 also includes a third terminal 1013 and a fourth terminal 1014. The third terminal 1013 is connected to the positive busbar 102, and the fourth terminal 1014 is connected to the negative busbar 103. When the motor controller 50 draws power from the external battery 40, the third terminal 1013 is connected to the positive terminal of the battery 40, and the fourth terminal 1014 is connected to the negative terminal of the battery 40. The motor controller 50 converts the DC power from the battery 40 into AC power that meets the requirements through the supporting capacitor module 10 and the power module 20, and outputs it.

[0112] Some embodiments of this application provide an electric drive system. The electric drive system includes... Figure 1 The system includes a motor controller 50 and a motor 30. The input terminal of the motor 30 is connected to the power module 20 of the motor controller 50. In this electric drive system, the AC power output from the power module 20 of the motor controller 50 is used to drive the motor 30.

[0113] Some embodiments of this application provide an automobile that includes the electric drive system described in the foregoing embodiments. Specifically, the output of the motor 30 in the electric drive system is connected to the wheels of the automobile via a transmission mechanism, thereby driving the automobile.

[0114] Some embodiments of this application provide an electronic device that includes the supporting capacitor module in any of the foregoing embodiments. Specifically, the electronic device can be various types of converters, such as traction converters, wind power converters, photovoltaic inverters, high-voltage frequency converters, etc.; the electronic device can also be an uninterruptible power supply (UPS), an emergency power supply (EPS), a static var generator (SVG), an active power filter (APF), etc.

[0115] The foregoing has provided a detailed description of the supporting capacitor module, motor controller, electric drive system, automobile, and electronic equipment provided in the embodiments of this application. Specific examples have been used to illustrate the principles and embodiments of this application. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in specific embodiments and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A capacitor support module, characterized in that, The supporting capacitor module includes: One or more pairs of terminals; each pair of terminals includes a first terminal and a second terminal for connecting to a power module; the power module includes multiple power switches; The first capacitor bank includes one or more capacitors, one end of which is connected to all the first terminals and the other end of which is connected to all the second terminals; The second capacitor bank includes one or more capacitors, one end of which is connected to all the first terminals and the other end of which is connected to all the second terminals; The first terminal forms a first current path to the second terminal via the first capacitor bank; The first terminal forms a second current path to the second terminal via the second capacitor bank; Within the first frequency range, the impedance of the first current path is less than the impedance of the second current path. Within the second frequency range, the impedance of the first current path is greater than the impedance of the second current path. The first frequency range is smaller than the second frequency range; The stray inductance of the first current path is greater than the stray inductance of the second current path.

2. The supporting capacitor module as described in claim 1, characterized in that, The resonant frequency of the first current path is located within the first frequency range, and the resonant frequency of the second current path is located within the second frequency range. and / or Within the first frequency range, the impedance of the first capacitor bank is less than the impedance of the second capacitor bank. Within the second frequency range, the impedance of the first capacitor bank is greater than the impedance of the second capacitor bank.

3. The supporting capacitor module as described in any one of claims 1-2, characterized in that, The equivalent capacitance of the first capacitor bank is greater than the equivalent capacitance of the second capacitor bank.

4. The supporting capacitor module as described in claim 3, characterized in that, The first capacitor bank includes at least one of film capacitors and electrolytic capacitors; and / or The second capacitor bank includes at least one of ceramic capacitors and film capacitors.

5. The supporting capacitor module as described in any one of claims 1-4, characterized in that, The equivalent series inductance of the first capacitor bank is greater than the equivalent series inductance of the second capacitor bank; and / or The length of the first current path is greater than the length of the second current path; and / or The magnetic coupling coefficient of the second current path is greater than that of the first current path.

6. The supporting capacitor module as described in any one of claims 1-5, characterized in that, The ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each power switch is 0.5-1.5; or The ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each power switch is 0.8-1.2; or The ratio of the resonant frequency of the second current path to the frequency of the falling edge of the turn-off current of each of the power switches is 0.9-1.

1.

7. The supporting capacitor module as described in any one of claims 1-6, characterized in that, The supporting capacitor module includes: The main busbar connects to all the first terminals; Negative busbar, connecting all second terminals; The two ends of the first capacitor bank are respectively connected to the positive busbar and the negative busbar; The two ends of the second capacitor bank are respectively connected to the positive busbar and the negative busbar; The direction of the current in the positive busbar is opposite to the direction of the current in the negative busbar.

8. The supporting capacitor module as described in claim 7, characterized in that, The positive busbar includes multiple positive busbar layers connected in parallel; The negative busbar includes multiple negative busbar layers connected in parallel; The plurality of positive busbar layers and the plurality of negative busbar layers are arranged in alternating layers; The first current path passes through the plurality of positive busbar layers and the plurality of negative busbar layers, and / or the second current path passes through the plurality of positive busbar layers and the plurality of negative busbar layers; The current direction in the plurality of positive busbar layers is opposite to the current direction in the plurality of negative busbar layers.

9. The supporting capacitor module as described in any one of claims 1-8, characterized in that, The first capacitor bank includes multiple capacitors connected in parallel; the multiple capacitors in the first capacitor bank are uniformly and symmetrically distributed near the power module; and / or The second capacitor bank includes multiple capacitors connected in parallel; the multiple capacitors in the second capacitor bank are evenly and symmetrically distributed near the power module.

10. The supporting capacitor module as described in any one of claims 1-9, characterized in that, The supporting capacitor module also includes a PCB board; The positive busbar and the negative busbar are located in the PCB board; The first capacitor bank and the second capacitor bank are located on opposite sides of the PCB board.

11. The supporting capacitor module as described in any one of claims 1-10, characterized in that, The supporting capacitor module also includes a PCB board; The one or more pairs of terminals and the second capacitor bank are respectively located in the same area on both sides of the PCB board.

12. The supporting capacitor module as described in any one of claims 1-10, characterized in that, The supporting capacitor module also includes a PCB board; The first terminal and the second terminal in each pair of terminals are located in the same area on both sides of the PCB board.

13. The supporting capacitor module as described in any one of claims 10-12, characterized in that, The supporting capacitor module also includes: A filter component is located on the PCB board and connected to the positive busbar and the negative busbar.

14. The supporting capacitor module as described in any one of claims 1-13, characterized in that, The first frequency range is 1kHz-20kHz; The second frequency range is 1MHz-100MHz.

15. A motor controller, characterized in that, The motor controller includes: The supporting capacitor module as described in any one of claims 1-14; The power module includes multiple power switches.

16. An electric drive system, characterized in that, The electric drive system includes: The motor controller as described in claim 15; The motor has its input terminal connected to the power module of the motor controller.

17. A car, characterized in that, The vehicle includes: The electric drive system as described in claim 16.

18. An electronic device, characterized in that, The electronic device includes: The supporting capacitor module as described in any one of claims 1-14.

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