Control method and device of balanced bridge circuit, electronic equipment and storage medium

Abstract

The application discloses a control method and device of a balanced bridge circuit, electronic equipment and a storage medium, relates to the technical field of balanced bridges, and obtains a neutral line voltage deviation value signal; controls the direct current and the alternating current of the neutral line voltage deviation value signal based on at least two control loops, obtains a direct current control signal and an alternating current control signal; adjusts an adjustment coefficient based on the neutral line voltage deviation value signal, and obtains a target adjustment coefficient; fuses the direct current control signal and the alternating current control signal based on the target adjustment coefficient, obtains a target control signal, and controls the balanced bridge based on the target control signal. The control method of the balanced bridge circuit controls the direct current and the alternating current of the neutral line voltage deviation value signal respectively, adjusts the adjustment coefficients of different control signals adaptively, and solves the problem of heating of the neutral line capacitor without affecting the control effect of the original positive bus voltage and the negative bus voltage.

Description

Technical Field

[0001] This application relates to the technical field of balanced bridge circuits, and in particular to a control method, device, electronic device, and storage medium for a balanced bridge circuit. Background Technology

[0002] When an energy storage converter is connected to an unbalanced load, the positive and negative bus voltages will become unbalanced. In related technologies, a balancer control circuit is mainly used to balance the positive and negative bus voltages. However, this balancer control strategy can only be used to adjust the balance of the positive and negative bus voltages and cannot solve the problem of the bus capacitor heating up due to the N-line (neutral) current flowing into the midpoint. Summary of the Invention

[0003] Therefore, the purpose of this application is to propose a control method, device, electronic device, and storage medium for a balanced bridge circuit, which controls the DC and AC quantities of the neutral voltage deviation signal respectively, and adds an adjustment coefficient to the control signal. The adjustment coefficient of different control signals is adaptively adjusted according to the specific situation of the neutral voltage deviation signal, so as to solve the problem of neutral capacitor heating without affecting the original positive and negative bus voltage control effect.

[0004] This application provides a control method for a balanced bridge circuit. The method includes: acquiring a neutral voltage deviation signal; controlling the DC and AC quantities of the neutral voltage deviation signal based on at least two control loops to obtain a DC control signal and an AC control signal; adjusting an adjustment coefficient based on the neutral voltage deviation signal to obtain a target adjustment coefficient; fusing the DC control signal and the AC control signal based on the target adjustment coefficient to obtain a target control signal; and controlling the balanced bridge based on the target control signal.

[0005] For example, the target adjustment coefficient includes a DC adjustment coefficient and an AC adjustment coefficient, the neutral voltage deviation signal includes a neutral voltage deviation value, and the adjustment of the adjustment coefficient based on the neutral voltage deviation signal includes: increasing the DC adjustment coefficient and decreasing the AC adjustment coefficient when the neutral voltage deviation value is greater than the neutral voltage deviation threshold; and increasing the AC adjustment coefficient and decreasing the DC adjustment coefficient when the neutral voltage deviation value is less than or equal to the neutral voltage deviation threshold.

[0006] For example, the target adjustment coefficient includes a DC adjustment coefficient and an AC adjustment coefficient. The step of fusing the control signal based on the target adjustment coefficient to obtain a target control signal includes: determining a first product between the DC control signal and the DC adjustment coefficient, and a second product between the AC control signal and the AC adjustment coefficient; and determining the sum of the first product and the second product as the target control signal.

[0007] For example, the at least two control loops include a first control loop and a second control loop. The step of controlling the DC and AC quantities of the neutral voltage deviation signal based on the at least two control loops includes: controlling the AC quantity of the neutral voltage deviation signal based on the first control loop to obtain the AC quantity control signal; and controlling the DC quantity of the neutral voltage deviation signal based on the second control loop to obtain the DC quantity control signal.

[0008] For example, the first control loop includes a first controller and a second controller connected together. The neutral voltage deviation signal is used as the input signal of the first controller. The output signal of the first controller is subtracted from the balance bridge current signal and then superimposed on the neutral current signal and input to the second controller. The second controller outputs the AC quantity control signal.

[0009] For example, the second control loop includes a third controller and a fourth controller connected together. The neutral voltage deviation signal is used as the input signal of the third controller. The output signal of the third controller is low-pass filtered, and the difference between it and the low-pass filtered balanced bridge current signal is calculated. The difference is then superimposed on the low-pass filtered neutral current signal and input to the fourth controller. The fourth controller outputs the DC control signal.

[0010] For example, the neutral voltage deviation value includes the difference between a preset multiple of the positive bus voltage and the negative bus voltage after low-pass filtering.

[0011] For example, the sum of the AC regulation coefficient and the DC regulation coefficient is an integer 1.

[0012] Another embodiment of this application provides a control device for a balanced bridge circuit. The device includes: an acquisition module for acquiring a neutral voltage deviation signal; a control module for controlling the DC and AC quantities of the neutral voltage deviation signal based on at least two control loops to obtain a DC control signal and an AC control signal; an adjustment module for adjusting an adjustment coefficient based on the neutral voltage deviation signal to obtain a target adjustment coefficient; and a fusion module for fusing the DC control signal and the AC control signal based on the target adjustment coefficient to obtain a target control signal, and controlling the balanced bridge based on the target control signal.

[0013] Another embodiment of this application provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the control method for the balanced bridge circuit described above.

[0014] Another embodiment of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the control method for the balanced bridge circuit described above.

[0015] In the above embodiments, a neutral voltage deviation signal is acquired; the DC and AC quantities of the neutral voltage deviation signal are controlled based on at least two control loops to obtain a DC control signal and an AC control signal; the adjustment coefficient is adjusted based on the neutral voltage deviation signal to obtain a target adjustment coefficient; the DC control signal and the AC control signal are fused based on the target adjustment coefficient to obtain a target control signal, and the balance bridge is controlled based on the target control signal. The control method of the balance bridge circuit of the present invention controls the DC and AC quantities of the neutral voltage deviation signal separately, and adds an adjustment coefficient to the control signal. The adjustment coefficients of different control signals are adaptively adjusted according to the specific situation of the neutral voltage deviation signal, thereby solving the problem of neutral capacitor heating without affecting the original positive and negative bus voltage control effect. Attached Figure Description

[0016] Figure 1 Topology diagram of a three-phase four-wire energy storage converter provided for embodiments of this application; Figure 2 A flowchart of a control method for a balanced bridge circuit provided in an embodiment of this application; Figure 3 A schematic diagram illustrating the control strategy provided in the embodiments of this application; Figure 4 A flowchart for fusing control signals is provided as an embodiment of this application; Figure 5 A schematic diagram of the control loop provided for an embodiment of this application; Figure 6 A schematic diagram of the control device for the balanced bridge circuit provided in the embodiments of this application; Figure 7 A block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0017] The embodiments of this application are described in detail below. Examples of the 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 intended to explain this application, and should not be construed as limiting this application.

[0018] The control method for the balanced bridge circuit of this application can be applied to low-power bus balancing circuits, such as the balanced bridge control in a three-phase four-wire energy storage converter. Of course, the application scenarios of the control method for the balanced bridge circuit of this application are not limited to three-phase four-wire energy storage converters; it can be used to solve the problem of neutral line overheating.

[0019] The following explanation uses a three-phase four-wire energy storage converter as an example.

[0020] Figure 1 This is a topology diagram of a three-phase four-wire energy storage converter according to an embodiment of this application. Figure 1 As shown, the external system of a three-phase four-wire energy storage converter includes a battery, a load, and a power grid. The product itself includes a DC-AC bidirectional circuit, such as a three-level DC-AC bidirectional circuit, as well as a bus balance bridge circuit, voltage, current, and temperature acquisition circuits, a digital control circuit, and a communication circuit. The battery in the external system is connected to the DC side of the energy storage converter, while the AC side is connected to the load or the power grid. Its main purpose is to control the energy storage converter to charge or discharge the battery. The DC-AC bidirectional circuit of the energy storage converter consists of power transistors, inductors, and capacitors. By controlling the power transistors in this circuit, DC-to-AC conversion or AC-to-DC conversion is achieved, thereby enabling the charging and discharging of the battery. The voltage, current, and temperature acquisition circuit collects information such as DC-side voltage and current, AC-side voltage and current, and temperature to achieve precise control of the charging and discharging voltage, current, and power, as well as system protection. The digital control circuit controls the power transistors in the DC-AC bidirectional circuit through PWM control signals output by the MCU (controller unit).

[0021] The control method for the balanced bridge circuit in this application can be executed by a controller (MCU) in a digital control circuit. This control method can be implemented in both off-grid and grid-connected scenarios for three-phase four-wire energy storage converters.

[0022] The control method of the balanced bridge circuit is explained in detail below.

[0023] As an example, such as Figure 2 As shown, the control methods for the balanced bridge circuit include: S201, acquire the neutral voltage deviation signal.

[0024] S202, based on at least two control loops, controls the DC and AC quantities of the neutral voltage deviation signal respectively, to obtain the DC control signal and the AC control signal.

[0025] S203 adjusts the adjustment coefficient based on the neutral voltage deviation signal to obtain the target adjustment coefficient.

[0026] S204, based on the target adjustment coefficient, fuses the DC flow control signal and the AC flow control signal to obtain the target control signal, and controls the balance bridge based on the target control signal.

[0027] For example, the control objective of the balanced bridge circuit is to maintain voltage balance between the positive and negative buses. This can be achieved by acquiring the neutral voltage deviation signal from the positive and negative bus voltages. It can be understood that the neutral voltage deviation signal represents the ideal value of the neutral voltage (e.g., as shown in the image). Figure 1 The deviation signal between the half of the positive bus voltage shown and the actual neutral voltage reflects the shift in the neutral point potential. By controlling the neutral voltage deviation signal, the neutral voltage deviation signal is made to approach zero, thereby achieving voltage balance between the positive and negative buses.

[0028] For example, this application controls the DC and AC components of the neutral voltage deviation signal based on at least two control loops. It is understood that this application inputs the neutral voltage deviation signal to different control lines, with at least one control line primarily controlling the DC component of the neutral voltage deviation signal and at least one control line primarily controlling the AC component of the neutral voltage deviation signal, resulting in control signals corresponding to different control lines, namely, DC control signals and AC control signals. Of course, the number of DC and AC control signals is not limited to one. For example, if two control loops are used to control the DC component of the neutral voltage deviation signal, then there will be two DC control signals. It can be understood that the control signals correspond to the control loops; the number of control loops determines the number of control signals output.

[0029] For example, this application introduces an adjustment coefficient, which can be used to adjust the proportion of control signals corresponding to different control circuits. Based on the specific situation of the neutral voltage deviation signal, the adjustment coefficient is adjusted to obtain the target adjustment coefficient for each control signal. Then, all control signals are fused based on the target adjustment coefficient, such as through weighted fusion, to obtain the final target control signal. The balanced bridge is controlled based on the target control signal to achieve voltage balance between the positive and negative buses of the balanced bridge, while also solving the problem of neutral capacitor heating.

[0030] The control method of the balanced bridge circuit in this application controls the DC and AC quantities of the neutral voltage deviation signal separately, and adds an adjustment coefficient to the control signal. The adjustment coefficient of different control signals is adaptively adjusted according to the specific situation of the neutral voltage deviation signal, so as to solve the problem of neutral capacitor heating without affecting the original positive and negative bus voltage control effect.

[0031] As an example, the neutral voltage deviation value includes the difference between a preset multiple of the positive bus voltage and the negative bus voltage after low-pass filtering.

[0032] For example, such as Figure 1 The topology diagram of the energy storage converter shown typically uses the same capacitor between the balanced bridge circuit and the DC / AC bidirectional circuit, so the preset multiple can be 0.5. The ideal value of the neutral voltage can be a preset multiple of the positive bus voltage, i.e., 0.5 times the positive bus voltage. In practice, due to inconsistencies in switching devices, load imbalance, etc., the voltages carried by the two capacitors may not be equal (i.e., positive and negative bus voltage imbalance). The voltage of the negative bus relative to the midpoint will deviate from 0.5 times the positive bus voltage. Low-pass filtering of the negative bus voltage is to filter out switching noise and high-frequency ripple, obtaining its DC component or low-frequency component. This application uses the difference between the preset multiple of the positive bus voltage and the low-pass filtered negative bus voltage as a parameter to represent the neutral voltage deviation, and controls the system with the neutral voltage deviation value being zero.

[0033] As an example, such as Figure 3 As shown, at least two control loops, including a first control loop and a second control loop, are used to control the DC and AC quantities of the neutral voltage deviation signal, respectively, based on the at least two control loops. This includes: Based on the first control loop, the AC quantity of the neutral voltage deviation signal is controlled to obtain the AC quantity control signal; The DC flow control signal is obtained by controlling the DC flow of the neutral voltage deviation signal based on the second control loop.

[0034] For example, this application uses two control loops as an example for illustration, such as Figure 3As shown, the first control loop is mainly used to control the AC quantity of the neutral voltage deviation signal. The difference between 0.5 times the positive bus voltage and the negative bus voltage after low-pass filtering (the neutral voltage deviation signal) is input to the first control loop, and the AC quantity control signal is output. Then, a proportional element is connected. The proportional coefficient of the proportional element is called the AC adjustment coefficient, which is used to adjust the AC quantity control signal.

[0035] For example, similarly, the second control loop is mainly used to control the DC output of the neutral voltage deviation signal. The difference between 0.5 times the positive bus voltage and the negative bus voltage after low-pass filtering (the neutral voltage deviation signal) is input to the second control loop, and the DC output control signal is output. It is also connected to a proportional element. The proportional coefficient of the proportional element is called the DC regulation coefficient. The DC regulation coefficient is used to adjust the DC control signal.

[0036] As an example, the target regulation coefficient includes both DC and AC regulation coefficients, the neutral voltage deviation signal includes the neutral voltage deviation value, and the regulation coefficient is adjusted based on the neutral voltage deviation signal, including: When the neutral voltage deviation is greater than the neutral voltage deviation threshold, increase the DC regulation coefficient and decrease the AC regulation coefficient. When the neutral voltage deviation is less than or equal to the neutral voltage deviation threshold, increase the AC regulation coefficient and decrease the DC regulation coefficient.

[0037] For example, a neutral voltage deviation threshold can be pre-configured. This threshold is determined based on system hardware attributes, typically the hardware capabilities of the energy storage converter, bus capacitor design, and installation requirements. Once the hardware and bus capacitor design of the energy storage converter are completed, the neutral voltage deviation threshold can be determined. The neutral voltage deviation threshold varies depending on the scenario. The neutral voltage deviation threshold is then used to judge the neutral voltage deviation value.

[0038] For example, when the neutral voltage deviation value is greater than the neutral voltage deviation threshold, it indicates that the deviation between the positive and negative bus voltages is large, meaning the positive and negative buses of the balancing bridge are unbalanced and need to be balanced. Since the DC current accounts for a larger proportion of the neutral current, the DC regulation coefficient is increased and the AC regulation coefficient is decreased. This means the DC control signal is primarily used to control the balance of the positive and negative buses, ensuring that the positive and negative buses of the balancing bridge reach equilibrium as quickly as possible, preventing AC current distortion, and guaranteeing normal system operation. For example, when the neutral voltage deviation is less than or equal to the neutral voltage deviation threshold, it indicates that the deviation between the positive and negative bus voltages is small, and there is no need to control the balance of the positive and negative buses. In this scenario, the AC current accounts for a larger proportion. At this time, increasing the AC regulation coefficient and decreasing the DC regulation coefficient, i.e., the AC control signal plays a dominant role, allows most of the neutral current to flow into the balance bridge. Figure 1 It can be seen that the neutral current either flows into the balance bridge or into the neutral capacitor. The majority of the neutral current flows into the balance bridge, which greatly reduces the current flowing into the bus capacitor, thereby improving the heating problem of the bus capacitor.

[0039] This application constructs two control loops to achieve AC and DC control of the neutral voltage deviation signal, respectively. Based on the neutral voltage deviation, the corresponding adjustment coefficient is dynamically adjusted. When the deviation is large, the DC adjustment coefficient is increased, primarily using DC to control the balance of the positive and negative buses, ensuring the effective control of the balance bridge's positive and negative bus balance. When the deviation is small, the AC adjustment coefficient is increased, primarily using AC to control the flow, ensuring that most of the neutral current flows into the balance bridge, thus mitigating the heating problem of the bus capacitors.

[0040] As an example, the sum of the AC regulation coefficient and the DC regulation coefficient is an integer of 1.

[0041] For example, the AC regulation coefficient can be K, and the DC regulation coefficient can be 1-K. When the AC regulation coefficient is increased, the DC regulation coefficient decreases accordingly. When the DC regulation coefficient is increased, the AC regulation coefficient decreases accordingly. Thus, the AC and DC regulation coefficients can be adjusted using a proportional coefficient K.

[0042] For example, when the neutral voltage deviation is less than or equal to the neutral voltage deviation threshold, the AC regulation coefficient is increased, for example, the AC regulation coefficient K is adjusted to between 0.5 and 1. The specific value can be determined according to the actual control effect. Correspondingly, the DC regulation coefficient is between 0 and 0.5. When the neutral voltage deviation is greater than the neutral voltage deviation threshold, the DC regulation coefficient is increased, for example, the AC regulation coefficient K is adjusted to between 0 and 0.5. Correspondingly, the DC regulation coefficient is between 0.5 and 1.

[0043] As an example, the control signals include DC control signals and AC control signals. The control signals are fused based on the target adjustment coefficient to obtain the target control signal, which includes: S401 determines the first product between the DC control signal and the DC regulation coefficient, and the second product between the AC control signal and the AC regulation coefficient.

[0044] S402, determine the sum of the first product and the second product as the target control signal.

[0045] For example, the target control signal is obtained by weighting the DC control signal and the AC control signal according to the adjusted target adjustment coefficient. Specifically, such as... Figure 3 As shown, the first control loop outputs an AC control signal, which is multiplied by the AC regulation coefficient. The second control loop outputs a DC control signal, which is multiplied by the DC regulation coefficient. The first product and the second product are added together to obtain the target control signal. The target control signal can be understood as a balanced bridge control signal, which can be a type of PWM control signal used to control the power transistors inside the energy storage converter.

[0046] As an example, such as Figure 5 As shown, the first control loop includes a first controller and a second controller connected together. The neutral voltage deviation signal is used as the input signal of the first controller. The output signal of the first controller is subtracted from the balanced bridge current signal and then superimposed on the neutral current signal and input to the second controller. The second controller outputs an AC control signal.

[0047] Exemplarily, the control loop of this application can be implemented using a controller, which can be one or more. This application uses a dual-loop controller as an example for illustration. The first control loop includes a first controller and a second controller connected together. It should be understood that the controller here is not a hardware device, but a control algorithm. The controller type can be proportional-integral, proportional-derivative, or proportional-integral-derivative controllers. This application also introduces feedforward control of the neutral current between the first controller and the second controller to increase the tracking speed of the neutral current, enabling the controller to respond faster. The output signal of the first controller is subtracted from the balanced bridge current signal, so that the second controller controls the error between the subtraction of the output signal of the first controller and the balanced bridge current signal. The second controller outputs an AC control signal.

[0048] As an example, such as Figure 5 As shown, the second control loop includes a third controller and a fourth controller connected together. The neutral voltage deviation signal is used as the input signal of the third controller. The output signal of the third controller is low-pass filtered, and the difference between it and the low-pass filtered balanced bridge current signal is calculated. The difference is then superimposed with the low-pass filtered neutral current signal and input to the fourth controller. The fourth controller outputs a DC control signal.

[0049] For example, the second control loop for DC component control adds a low-pass filter before each signal. The topology of the second control loop can also be a dual-loop controller, including a connected third and fourth controller. It is understood that the controller here is not a hardware device, but a control algorithm. The controller type can be proportional-integral, proportional-derivative, or proportional-integral-derivative. The neutral voltage deviation signal serves as the input signal to the third controller, enabling it to control the error between 0.5 times the positive bus voltage and the low-pass filtered negative bus voltage. The output signal of the third controller, after low-pass filtering, is subtracted from the low-pass filtered balanced bridge current signal, allowing the fourth controller to control the error between the output signal of the third controller and the balanced bridge current signal. This application also introduces feedforward control of the neutral current between the third and fourth controllers, adding a low-pass filtered neutral current to increase the tracking speed of the neutral current, enabling the controller to respond faster. Finally, the fourth controller outputs a DC control signal.

[0050] The control method of the balanced bridge circuit in this application, when the positive and negative buses are balanced (with small deviations), increases the AC regulation coefficient to minimize the flow of neutral current into the bus capacitor, thus greatly reducing the heating of the bus capacitor. When the deviation is small, the DC regulation coefficient is increased to filter out the AC component of the neutral current, and the control effect of the positive and negative buses is not affected. Furthermore, by adding neutral current feedforward control to the balanced bridge loop control, the loop response speed is faster and the control effect is better.

[0051] This application also proposes a control device for a balanced bridge circuit.

[0052] As an example, such as Figure 6 As shown, the control device for the balanced bridge circuit includes: The module 601 is used to acquire the neutral voltage deviation signal; the control module 602 is used to control the DC and AC quantities of the neutral voltage deviation signal based on at least two control loops to obtain a DC control signal and an AC control signal; the adjustment module 603 is used to adjust the adjustment coefficient based on the neutral voltage deviation signal to obtain a target adjustment coefficient; and the fusion module 604 is used to fuse the DC control signal and the AC control signal based on the target adjustment coefficient to obtain a target control signal, and to control the balance bridge based on the target control signal.

[0053] This application also proposes a computer-readable storage medium.

[0054] In this embodiment, a computer program is stored on a computer-readable storage medium, and when the computer program is executed by a processor, it implements the steps of the control method for the balanced bridge circuit described above.

[0055] Figure 7 A block diagram of an electronic device provided in an embodiment of this application.

[0056] This application provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the control method of the above-described balanced bridge circuit.

[0057] like Figure 7 As shown, for ease of understanding, embodiments of this application illustrate a specific electronic device.

[0058] Electronic devices are intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

[0059] like Figure 7 As shown, the device includes a computing unit 701, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 702 or a computer program loaded into a random access memory (RAM) 703 from a storage unit 708. The RAM 703 may also store various programs and data required for the operation of the electronic device. The computing unit 701, ROM 702, and RAM 703 are interconnected via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0060] Multiple components in the electronic device are connected to the I / O interface 705. These components include: an input unit 706, such as a keyboard or mouse; an output unit 707, such as various types of displays or speakers; a storage unit 708, such as a disk or optical disk; and a communication unit 709, such as a network interface card (NIC), a modem, or a wireless transceiver. The communication unit 709 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0061] The computing unit 701 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 701 performs the various methods described above, such as the control method for a balanced bridge circuit. For example, in some embodiments, the control method for a balanced bridge circuit can be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 708. In some embodiments, part or all of the computer program can be loaded and / or installed on an electronic device via ROM 702 and / or communication unit 709. When the computer program is loaded into RAM 703 and executed by the computing unit 701, the control method for a balanced bridge circuit described above can be performed. Alternatively, in other embodiments, the computing unit 701 can be configured to perform the control method for a balanced bridge circuit by any other suitable means (e.g., by means of firmware).

[0062] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this application, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0063] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0064] In the description of this application, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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.

[0066] Furthermore, the terms "first," "second," etc., used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of technical features indicated in this embodiment. Therefore, features defined with terms such as "first" and "second" in the embodiments of this application can explicitly or implicitly indicate that the embodiment includes at least one of those features. In the description of this application, the word "multiple" means at least two or more, such as two, three, four, etc., unless otherwise explicitly and specifically defined in the embodiments.

[0067] In this application, unless otherwise explicitly specified or limited in the embodiments, the terms "installation," "connection," "joining," and "fixing" appearing in the embodiments should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral part; it can also be a mechanical connection, an electrical connection, etc. Of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be 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 based on the specific implementation.

[0068] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0069] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A control method for a balanced bridge circuit, characterized in that, The method includes: Acquire the neutral voltage deviation signal; Based on at least two control loops, the DC and AC quantities of the neutral voltage deviation signal are controlled respectively to obtain DC control signals and AC control signals. The adjustment coefficient is adjusted based on the neutral voltage deviation signal to obtain the target adjustment coefficient; The DC control signal and the AC control signal are fused based on the target adjustment coefficient to obtain the target control signal, and the balance bridge is controlled based on the target control signal.

2. The control method for the balanced bridge circuit according to claim 1, characterized in that, The target adjustment coefficient includes a DC adjustment coefficient and an AC adjustment coefficient, the neutral voltage deviation signal includes a neutral voltage deviation value, and the adjustment of the adjustment coefficient based on the neutral voltage deviation signal includes: When the neutral voltage deviation value is greater than the neutral voltage deviation threshold, the DC regulation coefficient is increased and the AC regulation coefficient is decreased. When the neutral voltage deviation value is less than or equal to the neutral voltage deviation threshold, the AC regulation coefficient is increased and the DC regulation coefficient is decreased.

3. The control method for the balanced bridge circuit according to claim 1 or 2, characterized in that, The target regulation coefficient includes a DC regulation coefficient and an AC regulation coefficient. The process of fusing the control signal based on the target regulation coefficient to obtain the target control signal includes: Determine the first product between the DC control signal and the DC regulation coefficient, and the second product between the AC control signal and the AC regulation coefficient; The sum of the first product and the second product is determined to be the target control signal.

4. The control method for the balanced bridge circuit according to claim 1 or 2, characterized in that, The at least two control loops include a first control loop and a second control loop. The control of the DC and AC quantities of the neutral voltage deviation signal based on the at least two control loops includes: Based on the first control loop, the AC quantity of the neutral voltage deviation signal is controlled to obtain the AC quantity control signal; The DC flow rate of the neutral voltage deviation signal is controlled based on the second control loop to obtain the DC flow rate control signal.

5. The control method for the balanced bridge circuit according to claim 4, characterized in that, The first control loop includes a first controller and a second controller connected together. The neutral voltage deviation signal is used as the input signal of the first controller. The output signal of the first controller is subtracted from the balanced bridge current signal and then superimposed on the neutral current signal and input to the second controller. The second controller outputs the AC quantity control signal.

6. The control method for the balanced bridge circuit according to claim 4, characterized in that, The second control loop includes a third controller and a fourth controller connected together. The neutral voltage deviation signal is used as the input signal of the third controller. The output signal of the third controller is low-pass filtered, and the difference between it and the low-pass filtered balanced bridge current signal is calculated. The difference is then superimposed with the low-pass filtered neutral current signal and input to the fourth controller. The fourth controller outputs the DC control signal.

7. The control method for the balanced bridge circuit according to claim 2, characterized in that, The neutral voltage deviation value includes the difference between a preset multiple of the positive bus voltage and the negative bus voltage after low-pass filtering.

8. The control method for the balanced bridge circuit according to claim 2, characterized in that, The sum of the AC regulation coefficient and the DC regulation coefficient is an integer 1.

9. A control device for a balanced bridge circuit, characterized in that, The device includes: The acquisition module is used to acquire the neutral voltage deviation signal; The control module is used to control the DC and AC quantities of the neutral voltage deviation signal based on at least two control loops, respectively, to obtain DC control signals and AC control signals. The adjustment module is used to adjust the adjustment coefficient based on the neutral voltage deviation signal to obtain the target adjustment coefficient; The fusion module is used to fuse the DC flow control signal and the AC flow control signal based on the target adjustment coefficient to obtain a target control signal, and to control the balance bridge based on the target control signal.

10. An electronic device, characterized in that, The device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the control method for the balanced bridge circuit according to any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed by a processor, implements the steps of the control method for the balanced bridge circuit according to any one of claims 1-8.

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