Voltage balancing method, voltage balancing circuit, electronic equipment and storage medium

Abstract

The invention provides a voltage balancing method, a controller and a storage medium, which are applied to a control circuit connected with a rectification circuit, the control circuit is used for controlling the working mode of the rectification circuit, the first input end of the rectification circuit is connected with a first DC bus, the second input end is connected with a second DC bus, and the output end is connected with a load. The first end of the first bus capacitor is connected with the first DC bus, the second end is connected with the neutral point of the rectification circuit, and the first end of the second bus capacitor is connected with the neutral point and the second end is connected with the second DC bus. The voltage balancing method comprises the following steps: acquiring a first voltage of a first bus capacitor and a second voltage of a second bus capacitor; and a voltage difference value between the first voltage and the second voltage and corresponding difference value change information are obtained to confirm the working mode of the rectification circuit so as to balance the voltage of the neutral point. By adopting the provided voltage balancing method, a corresponding current sensor does not need to be arranged in the rectifying circuit, so that the design cost of the rectifying circuit is reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a voltage balancing method, a voltage balancing circuit, an electronic device and a storage medium. Background Art

[0002] Half-bus voltage balancing technology is the core technology to ensure the operation of three-level rectifier circuits. The existing voltage balancing algorithm determines the current direction and the voltage difference between the upper and lower bus capacitors. In order to balance the voltage difference between the neutral points of the upper and lower bus capacitors, a corresponding voltage balancing working mode needs to be adopted. This method requires two voltage sensors and one current sensor to be set in the rectifier circuit to complete the switching of the voltage balancing working mode. Corresponding current sensors need to be arranged for different current sizes of the rectification circuit, resulting in a high design cost for the rectifier circuit. Summary of the invention

[0003] The main purpose of the present application is to provide a voltage balancing method, a voltage balancing circuit, an electronic device and a storage medium, which are used to solve the problem that the rectifier circuit needs to be arranged with corresponding current sensors to balance the voltage difference at the neutral point between the upper and lower bus capacitors, resulting in high design costs for the rectifier circuit.

[0004] In a first aspect, an embodiment of the present application provides a voltage balancing method, which is applied to a control circuit, wherein the control circuit is connected to a rectifier circuit and is used to control the working mode of the rectifier circuit, wherein a first input end of the rectifier circuit is connected to a first DC bus, a second input end of the rectifier circuit is connected to a second DC bus, an output end of the rectifier circuit is used to connect a load, a first end of a first bus capacitor is connected to the first DC bus, a second end of the first bus capacitor is connected to a neutral point of the rectifier circuit, a first end of a second bus capacitor is connected to the neutral point, and a second end of the second bus capacitor is connected to the second DC bus; the method comprises:

[0005] Acquire a first voltage of the first bus capacitor and a second voltage of the second bus capacitor;

[0006] Obtaining a voltage difference between the first voltage and the second voltage, and obtaining difference change information corresponding to the voltage difference;

[0007] The working mode of the rectifier circuit is confirmed according to the voltage difference and the difference change information, so as to balance the voltage of the neutral point.

[0008] In a second aspect, an embodiment of the present application provides a voltage balancing circuit, comprising a rectifier circuit and a control circuit, wherein the control circuit is connected to the rectifier circuit and is used to control the working mode of the rectifier circuit, a first input end of the rectifier circuit is connected to a first DC bus, a second input end of the rectifier circuit is connected to a second DC bus, an output end of the rectifier circuit is used to connect a load, a first end of a first bus capacitor is connected to the first DC bus, a second end of the first bus capacitor is connected to a neutral point of the rectifier circuit, a first end of a second bus capacitor is connected to the neutral point, and a second end of the second bus capacitor is connected to the second DC bus; wherein the control circuit implements the steps of a voltage balancing method as described in any one of the embodiments of the present application.

[0009] In a third aspect, an embodiment of the present application provides an electronic device, comprising a voltage balancing circuit as described in any one of the embodiments of the present application.

[0010] In a fourth aspect, an embodiment of the present application provides a storage medium for computer-readable storage, wherein the storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the voltage balancing method as described in any one of the embodiments of the present application.

[0011] The present application provides a voltage balancing method, a controller and a storage medium, which are applied to a control circuit connected to a rectifier circuit, wherein the control circuit is used to control the working mode of the rectifier circuit, wherein the first input end of the rectifier circuit is connected to the first DC bus, the second input end is connected to the second DC bus, the output end of the rectifier circuit is used to connect the load, the first end of the first bus capacitor is connected to the first DC bus, the second end is connected to the neutral point of the rectifier circuit, the first end of the second bus capacitor is connected to the neutral point, and the second end is connected to the second DC bus. The voltage balancing method provided obtains the first voltage of the first bus capacitor and the second voltage of the second bus capacitor; obtains the voltage difference between the first voltage and the second voltage, obtains the difference change information corresponding to the voltage difference; and confirms the working mode of the rectifier circuit according to the voltage difference and the difference change information, which is used to balance the voltage at the neutral point. The voltage balancing method provided is used to confirm the working mode of the rectifier circuit through the voltage difference between the first voltage of the first bus capacitor and the second voltage of the second bus capacitor and the difference change information of the voltage difference, without the need to provide a corresponding current sensor in the rectifier circuit, thereby reducing the design cost of the rectifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic structural block diagram of a voltage balancing circuit provided in an embodiment of the present application;

[0013] Figure 2 is a schematic block diagram of the structure of another voltage balancing circuit provided in an embodiment of the present application;

[0014] Figure 3 is a circuit diagram of a rectifier circuit provided in an embodiment of the present application;

[0015] Figure 4 is a schematic diagram of an equivalent circuit of a first working mode provided in an embodiment of the present application;

[0016] Figure 5 is a schematic diagram of an equivalent circuit of a second working mode provided in an embodiment of the present application;

[0017] Figure 6 is a schematic block diagram of the structure of another voltage balancing circuit provided in an embodiment of the present application;

[0018] Figure 7 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application;

[0019] Figure 8 is a schematic flow chart of the steps of a voltage balancing method provided in an embodiment of the present application;

[0020] Fig. 9 is a schematic flow chart of the steps of a working mode control method provided in an embodiment of the present application;

[0021] Fig.10 is a schematic flow chart of the steps of another voltage balancing method provided in an embodiment of the present application;

[0022] Fig.11 It is a schematic block diagram of a terminal device provided in an embodiment of the present application.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0026] It should be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be understood that, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first bus capacitor and the second bus capacitor are only used to distinguish different bus capacitors, and their order is not limited. Those skilled in the art can understand that the words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not necessarily limit them to be different.

[0028] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] See also Figure 1 , Figure 1 The schematic block diagram of the structure of a voltage balancing circuit 10 provided in an embodiment of the present application is shown. The voltage balancing circuit 10 includes a rectifier circuit 11 and a control circuit 12. The control circuit 12 is connected to the rectifier circuit 11 and is used to control the working mode of the rectifier circuit 11. The first input end of the rectifier circuit 11 is connected to the first DC bus, the second input end of the rectifier circuit 11 is connected to the second DC bus, the output end of the rectifier circuit 11 is used to connect the load 20, the first end of the first bus capacitor 30 is connected to the first DC bus, the second end of the first bus capacitor 40 is connected to the neutral point of the rectifier circuit 11, the first end of the second bus capacitor 40 is connected to the neutral point, and the second end of the second bus capacitor 40 is connected to the second DC bus. Among them, the control circuit 12 implements the steps of the voltage balancing method provided in any one of the embodiments of the present application to achieve the balance of the neutral point voltage.

[0031] Specifically, the rectifier circuit 11 is used to convert AC power into DC power to supply power to the load 20 via the first bus capacitor 30 and the second bus capacitor 40. When the voltages of the first bus capacitor 30 and the second bus capacitor 40 are different, the neutral point offset will cause the power switch devices inside the rectifier circuit 11 to be unevenly pressurized, causing the power switch devices to be broken down, and the neutral point voltage offset will also cause the grid-side current to be distorted, increase the harmonic content, affect the overall performance of the rectifier circuit 11, and be detrimental to the long-term stable operation of the rectifier circuit 11. Therefore, it is necessary to change the working mode of the rectifier circuit 11 through the control circuit 12 to achieve the balance of the neutral point voltage.

[0032] In some embodiments, the first DC bus is a positive DC bus, and the second DC bus is a negative DC bus. In some embodiments, the first DC bus is a negative DC bus, and the second DC bus is a positive DC bus. The embodiment of the present application does not limit the types of the first DC bus and the second DC bus.

[0033] In some embodiments, Figure 2 As shown, Figure 2 FIG. 1 is a schematic block diagram showing the structure of another voltage balancing circuit 10 provided in an embodiment of the present application. Figure 2 In the embodiment, the rectifier circuit 11 includes a first switch unit 111 and a second switch unit 112, wherein the first end of the first switch unit 111 is connected to the first end of the preset power supply, the second end of the first switch unit 111 is connected to the first DC bus, and the control end of the first switch unit 111 is connected to the control circuit 12. The first end of the second switch unit 112 is connected to the first end of the preset power supply, the second end of the second switch unit 112 is connected to the second DC bus, the control end of the second switch unit 112 is connected to the control circuit 12, and the second end of the preset power supply is connected to the neutral point. By arranging the first switch unit 111 and the second switch unit 112 in the rectifier circuit 11, when the first switch unit 111 is turned on, the first bus capacitor 30 is in a charging state, and when the second switch unit 112 is turned on, the second bus capacitor 40 is in a charging state, and then the control circuit 11 can adjust the working mode of the rectifier circuit 11 by turning on and off the first switch unit 111 and the second switch unit 112.

[0034] In some embodiments, the rectifier circuit 11 can be a two-phase circuit, a three-phase circuit, or a four-phase circuit. The number of phases of the rectifier circuit 11 is related to the working requirements of the actual voltage balancing circuit 10. The embodiments of the present application do not limit the type of the rectifier circuit 10.

[0035] Exemplarily, the rectifier circuit 11 is a diode clamped single-phase three-level rectifier circuit. Figure 3 , Figure 3The circuit diagram of a rectifier circuit 11 provided in an embodiment of the present application is shown. The rectifier circuit 11 is used to convert the power supply u s The input AC power is converted into DC power to supply power to the load R. The rectifier circuit 11 includes a plurality of switch tubes S a1 , S a2 , S a3 , S a4 , S b1 , S b2 , S b3 and S b4 The control end of each switch tube is connected to the control circuit 11, and the control circuit 11 switches the working mode of the rectifier circuit 11 by controlling the on and off of each switch tube in the rectifier circuit 11.

[0036] For example, when the neutral point voltage between the first bus capacitor C1 and the second bus capacitor C2 is offset, the control circuit 11 controls the rectifier circuit to adopt the first working mode or the second working mode to balance the neutral point voltage. Figure 4 As shown, Figure 4 The equivalent circuit diagram of a first working mode provided by an embodiment of the present application is shown. In the first working mode, the first bus capacitor C1 is in a charging state, and the second bus capacitor C1 is in a discharging state. When the voltage of the second bus capacitor C2 is greater than the voltage of the first bus capacitor C1, the first working mode can reduce the voltage difference between the first bus capacitor C1 and the second bus capacitor C2. Figure 5 As shown, Figure 5 The equivalent circuit diagram of a second working mode provided by an embodiment of the present application is shown. In the second working mode, the second bus capacitor C1 is in a charging state, and the first bus capacitor C1 is in a discharging state, and then when the voltage of the first bus capacitor C1 is greater than the voltage of the second bus capacitor C2, the second working mode can reduce the voltage difference between the first bus capacitor C1 and the second bus capacitor C2.

[0037] In some embodiments, Figure 6 As shown, Figure 6 FIG. 1 is a schematic block diagram showing the structure of another voltage balancing circuit 10 provided in an embodiment of the present application. Figure 6 In the figure, the first bus capacitor 30 and the second bus capacitor 40 are respectively connected to the first end of the voltage sensor, and the second end of the voltage sensor is connected to the control circuit 12, which is used to send the voltage of the first bus capacitor 30 and the second bus capacitor 40 to the control circuit 12, so that the control circuit 12 can control the working mode of the rectifier circuit 11 according to the voltage difference between the first bus capacitor 30 and the second bus capacitor 40.

[0038] For example, since the AC current is a periodic zero-crossing signal, the current direction is generally changed once every half cycle, generally 10ms or 8.7ms. Therefore, the control circuit 12 uses 10ms or 8.7ms as a sampling period to obtain the first voltage and the second voltage to confirm the working mode of the rectifier circuit 11.

[0039] In some embodiments, the control circuit 12 uses a space vector pulse width modulation (SVPWM) method to control the on and off of the switch inside the rectifier circuit 11 , thereby outputting a voltage value required by the load 20 .

[0040] In some embodiments, the control circuit 12 uses a microcontroller unit (MCU), which can control the working mode of the rectifier circuit 11 during the operation of the rectifier circuit 11 to achieve a balance of the neutral point voltage.

[0041] See also Figure 7 , Figure 7 1 is a schematic diagram of the structure of an electronic device 100 provided in an embodiment of the present application. Figure 7 As shown, the electronic device 100 includes: a voltage balancing circuit 10 provided by any embodiment of the present application.

[0042] In some embodiments, the electronic device 100 may be a power supply device or an energy storage device, and this embodiment does not limit the type of the electronic device.

[0043] In some embodiments, the voltage balancing circuit 10 may refer to Figures 1 to 6 For example, the voltage balancing circuit 10 includes the rectifier circuit 11 and the control circuit 12 described in the above embodiment. The specific configuration of the voltage balancing circuit 10 can refer to the corresponding embodiment recorded in the specification of the present invention, and this embodiment will not be repeated here.

[0044] By using the voltage balancing circuit 10 provided in the embodiment of the present application, the working mode of the rectifier circuit 11 is set through the control circuit 12 to balance the voltage difference between the first bus capacitor 30 and the second bus capacitor 40. No corresponding current sensor is required to be set inside the rectifier circuit 11, thereby reducing the design cost of the rectifier circuit 11.

[0045] See also Figure 8 , Figure 8 A schematic flow chart showing the steps of a voltage balancing method provided in an embodiment of the present application is shown. The voltage balancing method provided is applied to Figures 1 to 6 The control circuit 12 of the voltage balancing circuit 10 provided in any one of the embodiments.

[0046] like Figure 8 As shown, the provided voltage balancing method includes steps S101 to S103.

[0047] S101. Obtain a first voltage of a first bus capacitor and a second voltage of a second bus capacitor.

[0048] For details, please refer to Figure 6 , the control circuit 12 obtains the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40 through the voltage sensor. Based on the first voltage and the second voltage, the control circuit 12 can determine whether the voltage of the neutral point between the first bus capacitor 30 and the second bus capacitor 40 is offset. When confirming that the voltage of the neutral point is offset, the control circuit 12 can timely complete the balance of the neutral point voltage by controlling the working mode of the rectifier circuit 11.

[0049] S102. Obtain a voltage difference between the first voltage and the second voltage, and obtain difference change information corresponding to the voltage difference.

[0050] Specifically, after obtaining the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40, the control circuit 12 obtains the voltage difference between the first bus voltage and the second bus voltage, for example, by subtracting the second voltage from the first voltage. If the voltage difference is a positive number, it is determined that the first voltage of the first bus capacitor 30 is higher at this time, and the first bus capacitor 30 needs to be discharged or the second bus capacitor 40 needs to be charged to eliminate the voltage difference. Similarly, when the voltage difference is a negative number, it is determined that the second voltage of the second bus capacitor 40 is higher at this time, and the second bus capacitor 40 needs to be discharged or the first bus capacitor 30 needs to be charged to eliminate the voltage difference.

[0051] Since the control circuit 12 can periodically sample the first voltage and the second voltage, the voltage difference between the first voltage and the second voltage sampled in this cycle is compared with the voltage difference sampled in the previous cycle, and the difference change information corresponding to the voltage difference can be obtained. The change information of the voltage difference can characterize whether the voltage difference is in an increasing or decreasing state compared with the previous cycle. If the voltage difference is in an increasing state, the controller needs to switch the working mode of the rectifier circuit 11 at this time. Of course, it can be understood that the change information of the voltage difference refers to the change of the voltage difference with the change of the time.

[0052] S103. According to the voltage difference and the difference change information, the working mode of the rectifier circuit is determined to balance the voltage of the neutral point.

[0053] Specifically, the controller can determine whether it is necessary to switch the working mode of the rectifier circuit 11 at this time according to the voltage difference between the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40 and the difference change information. For example, when the voltage difference of the first voltage minus the second voltage is a positive number, and the difference change information is that the voltage difference is getting bigger and bigger at this time, then the controller needs to switch the working mode of the rectifier circuit 11 to a working mode in which the second bus capacitor 40 is charged and the first bus capacitor 30 is discharged, and then the neutral point voltage can be balanced according to the voltage difference and the difference change information. The voltage balancing method provided can confirm the working mode of the rectifier circuit 11 without the need for a corresponding current sensor in the rectifier circuit 11, thereby reducing the design cost of the rectifier circuit 11.

[0054] In some embodiments, please combine Figure 4 and Figure 5 , the working modes include the first working mode and the second working mode. Figure 4 As shown, the first working mode is used to charge the first bus capacitor 30. Figure 5 As shown, the second working mode is used to charge the second bus capacitor 40. When the working mode of the rectifier circuit 11 is the first working mode, the working mode of the rectifier circuit 11 is confirmed according to the voltage difference and the difference change information, including: confirming whether it is necessary to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode according to the voltage difference and the difference change information; wherein, if the difference change information is getting larger and larger and the voltage difference is a positive number, it is confirmed that the working mode of the rectifier circuit 11 needs to be switched from the first working mode to the second working mode.

[0055] When the difference change information obtained by the control circuit 12 is getting bigger and bigger and the voltage difference is a positive number, at this time, the voltage of the first bus capacitor 30 is greater than the second bus capacitor 40 and the current working mode of the rectifier circuit 11 will amplify the voltage difference, so it is confirmed that the current first working mode is wrong and needs to be switched to the second working mode, such as Figure 5 As shown, in the second working mode, the first capacitor is in a discharging state and the second capacitor is in a charging state, which can suppress the increase of the voltage difference to gradually eliminate the voltage difference and achieve the balance of the neutral point.

[0056] In some embodiments, please combine Figure 4 and Figure 5, when the working mode of the rectifier circuit 11 is the first working mode, the working mode of the rectifier circuit 11 is confirmed according to the voltage difference and the difference change information, including: confirming whether it is necessary to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode according to the voltage difference and the difference change information; wherein, if the difference change information is getting smaller and smaller and the voltage difference is a negative number, it is confirmed that the working mode of the rectifier circuit 11 needs to be switched from the first working mode to the second working mode.

[0057] When the difference change information is getting smaller and smaller and the voltage difference is a negative number, if the first working mode is used at this time, the second voltage of the second bus capacitor 40 will increase and the first bus capacitor 30 will decrease, causing the voltage difference to increase. Therefore, it is necessary to switch the working mode to the second working mode, which can promote the reduction of the voltage difference to gradually eliminate the voltage difference and achieve the balance of the neutral point.

[0058] In some embodiments, please combine Figure 4 and Figure 5 , when the working mode of the rectifier circuit 11 is the second working mode, the working mode of the rectifier circuit 11 is confirmed according to the voltage difference and the difference change information, including: confirming whether it is necessary to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode according to the voltage difference and the difference change information; wherein, if the difference change information is getting larger and larger and the voltage difference is a negative number, it is confirmed that the working mode of the rectifier circuit 11 needs to be switched from the second working mode to the first working mode.

[0059] When the difference change information is getting bigger and bigger and the voltage difference is a negative number, if the second working mode is used at this time, the second voltage of the second bus capacitor 40 will increase and the first bus capacitor 30 will decrease, causing the voltage difference to increase. Therefore, it is necessary to switch the working mode to the first working mode, which can promote the reduction of the voltage difference to gradually eliminate the voltage difference and achieve the balance of the neutral point.

[0060] In some embodiments, please combine Figure 4 and Figure 5 , when the working mode of the rectifier circuit 11 is the second working mode, the working mode of the rectifier circuit 11 is confirmed according to the voltage difference and the difference change information, including: confirming whether it is necessary to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode according to the voltage difference and the difference change information; wherein, if the difference change information is getting smaller and smaller and the voltage difference is a positive number, it is confirmed that the working mode of the rectifier circuit 11 needs to be switched from the second working mode to the first working mode.

[0061] When the difference change information is getting smaller and smaller and the voltage difference is a positive number, if the second working mode is used at this time, the second voltage of the second bus capacitor 40 will increase and the first bus capacitor 30 will decrease, causing the voltage difference to increase. Therefore, it is necessary to switch the working mode to the first working mode, which can promote the reduction of the voltage difference to gradually eliminate the voltage difference and achieve the balance of the neutral point.

[0062] In some embodiments, please refer to Figure 2 and Fig. 9 , Fig. 9 A schematic flowchart of the steps of a working mode control method provided in an embodiment of the present application is shown.

[0063] like Fig. 9 As shown, the provided method includes steps S201 to S202.

[0064] S201. Generate a first control signal, where the first control signal is used to turn on the first switch unit and turn off the second switch unit, so that the rectifier circuit is in a first working mode.

[0065] S202. Generate a second control signal, where the second control signal is used to control the second switch unit to be turned on and the first switch unit to be turned off, so that the rectifier circuit is in a second working mode.

[0066] When the controller determines that the first bus capacitor 30 is smaller than the second bus capacitor 40, the following needs to be adopted: Figure 4 When the first bus capacitor 30 is charged in the first working mode shown, a first control signal is generated to make the rectifier circuit 11 in the first working mode. Similarly, when the controller determines that the first bus capacitor 30 is greater than the second bus capacitor 40 at this time, it is necessary to adopt the following Figure 5 When the second working mode shown is used to charge the second bus capacitor 40, a second control signal is generated to put the rectifier circuit 11 in the second working mode. The controller can ensure that the rectifier circuit 11 is in the correct working mode by generating the first control signal and the second control signal.

[0067] In some embodiments, please refer to Fig.10 , Fig.10 is a schematic flow chart of the steps of another voltage balancing method provided in an embodiment of the present application, and Figure 6 The difference between the methods provided is that Fig.10 The provided method includes steps S103a to S103b.

[0068] S103a. Binarize the voltage difference to obtain a first binarization result, and binarize the difference change information to obtain a second binarization result.

[0069] S103b. Determine the operating mode of the rectifier circuit according to the product of the first binarization result and the second binarization result.

[0070] By binarizing the voltage difference and the difference change information, the voltage offset of the neutral point can be more concisely characterized. For example, when the voltage difference is a positive number, the first binarization result is assigned to 1, and when the voltage difference is a negative number, the first binarization result is assigned to -1. At this time, it can be clearly understood that when the first binarization result is 1, the first voltage of the first bus capacitor 30 is greater than the second voltage of the second bus capacitor 40. For the binarization of the difference change information, the difference information is characterized by numerical values ​​as getting bigger or smaller. For example, when the difference information is getting bigger, the second binarization result is assigned to -1, and when the difference information is getting smaller, the second binarization result is assigned to 1, and then the change of the voltage difference at this time can be clearly determined by the assignment of the second binarization result. And by multiplying the first binarization result and the second binarization result, the product is matched with the working mode, and then the controller can quickly confirm the working mode of the rectifier circuit 11, which greatly improves the efficiency of the provided voltage balancing method.

[0071] Exemplarily, binarizing the voltage difference to obtain a first binarization result, and binarizing the difference change information to obtain a second binarization result, includes: assigning the first binarization result to a first value when the voltage difference is a positive number, and assigning the first binarization result to a second value when the voltage difference is a negative number. When the difference change information indicates that the absolute value of the voltage difference increases, the second binarization result is assigned to a second value, and when the absolute value of the voltage difference decreases, the second binarization result is assigned to the first value. The first value is a positive number, and the second value is a negative number.

[0072] In order to facilitate the use of numerical values ​​to judge the content reflected by the voltage difference and the difference change information, by setting the first numerical value of a positive number and the second numerical value of a negative number, for example, the first numerical value is 1 and the second numerical value is -1, the offset condition of the neutral point at this time can be quickly judged based on the assignment of the first binarization result and the second binarization result, so that the controller can quickly confirm the working mode of the rectifier circuit 11.

[0073] It should be noted that the absolute value of the voltage difference between the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40 is used to judge the second binarization result because the purpose of the voltage balancing method provided in the present application is to balance the voltage difference between the first bus capacitor 30 and the second bus capacitor 40. Therefore, it is only necessary to judge whether the overall difference change trend is increasing or decreasing, and whether the first voltage of the first bus capacitor 30 is larger or the second voltage of the second bus capacitor 40 is larger can be characterized according to the first binarization result.

[0074] It should be noted that, in some embodiments, the difference change information is to construct a function to derive the absolute value of the voltage difference within the preset time, and when the derivative is greater than 0, it means that the absolute value of the voltage difference increases within the preset time, and when the derivative is less than 0, it means that the absolute value of the voltage difference decreases within the preset time. In some embodiments, the difference change information is to perform a differential calculation on the absolute value of the voltage difference within the preset time, and when the differential value is greater than 0, it means that the absolute value of the voltage difference increases within the preset time, and when the differential value is less than 0, it means that the absolute value of the voltage difference decreases within the preset time.

[0075] It should be noted that, in some embodiments, the first value is a negative number and the second value is a positive number. The first value and the second value are divided into positive and negative numbers so that the controller can judge the offset condition of the neutral point at this time. The judgment rule can be set according to the assignment of the first value and the second value. Therefore, the embodiment of the present application does not limit the positive and negative of the first value and the second value.

[0076] It should be noted that, in some embodiments, the working mode includes a first working mode and a second working mode, the first working mode is used to charge the first bus capacitor 30, and the second working mode is used to charge the first bus capacitor 30. When the working mode of the rectifier circuit 11 is the first working mode, the working mode of the rectifier circuit 11 is determined according to the product of the first binarization result and the second binarization result, including: if the second binarization result is a negative number, generating a request information, the request information is used to request to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode. If the product is a negative number, executing the request information.

[0077] Please refer to Figure 4 , when the rectifier circuit 11 is in the first working mode to charge the first bus capacitor 30, when the second binarization result is a negative number, the controller determines that the voltage difference is in a state of increasing, so the controller generates a request message to switch the working mode of the rectifier circuit 11 to the second working mode. If the second bus capacitor 40 is greater than the voltage of the first bus capacitor 30 at this time, switching to the second working mode will cause the voltage difference to continue to increase. Therefore, by executing the request message again when the product is a negative number, it can be further ensured that the controller can switch the rectifier circuit 11 to the correct working mode to achieve neutral point balance.

[0078] It should be noted that, in some embodiments, the working mode includes a first working mode and a second working mode, the first working mode is used to charge the first bus capacitor 30, and the second working mode is used to charge the first bus capacitor 30. When the working mode of the rectifier circuit 11 is the second working mode, the working mode of the rectifier circuit 11 is determined according to the product of the first binarization result and the second binarization result, including: if the second binarization result is a negative number, generating a request information, the request information is used to request to switch the working mode of the rectifier circuit 11 from the first working mode to the second working mode. If the product is a positive number, executing the request information.

[0079] Please refer to Figure 5 , when the rectifier circuit 11 is in the second working mode to charge the second bus capacitor 40, when the second binarization result is a negative number, the controller determines that the voltage difference is in a state of increasing, so the controller generates a request message to switch the working mode of the rectifier circuit 11 to the second working mode. If the voltage of the first bus capacitor 30 is greater than that of the second bus capacitor 40 at this time, switching to the first working mode will cause the voltage difference to continue to increase. Therefore, by executing the request message again when the product is a positive number, it can be further ensured that the controller can switch the rectifier circuit 11 to the correct working mode to achieve neutral point balance.

[0080] In some embodiments, obtaining the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40 includes: sampling according to twice the switching cycle to obtain multiple first voltages and second voltages. The switching cycle is the time interval between the current update and the next update pulse of the pulse width modulation signal output by the preset power supply connected to the input end of the rectifier circuit 11.

[0081] Since the alternating current input by the rectifier circuit 11 is a periodic zero-crossing signal, the controller needs to consider that if the sampled voltage of the first bus capacitor 30 and the second bus capacitor 40 is a voltage near the zero point, the voltage difference and the difference change trend will become opposite after the zero point. Therefore, if the controller controls the working mode of the rectifier circuit 11 based on the voltage difference and the difference change trend calculated by the voltage near the zero point, it may cause the confirmed working mode to be wrong, resulting in a more serious neutral point cheapness. Therefore, by sampling twice the switching cycle as a group, and summing up multiple groups of voltage differences and difference change trends calculated according to multiple first voltages and second voltages, the controller confirms the working mode of the rectifier circuit 11 according to the summed voltage difference and difference change trend, which can effectively eliminate the zero-crossing disturbance phenomenon. For example, the data before and after the zero point are summed to 0, which will not affect the confirmation of the working mode.

[0082] The voltage balancing method provided in the embodiment of the present application confirms the working mode of the rectifier circuit 11 through the voltage difference between the first voltage of the first bus capacitor 30 and the second voltage of the second bus capacitor 40 and the difference change information of the voltage difference. There is no need to install a corresponding current sensor in the rectifier circuit 11, thereby reducing the design cost of the rectifier circuit 11.

[0083] See also Fig.11 , Fig.11 A terminal device is shown. Fig.11 As shown, an embodiment of the present application proposes a terminal device 200, which includes a memory 210, a processor 220, a program stored in the memory and executable on the processor, and a data bus 230 for realizing connection and communication between the processor 220 and the memory 210. When the program is executed by the processor, the steps of the voltage balancing method as described in any one of the embodiments of the present application are realized.

[0084] An embodiment of the present application provides a storage medium for computer-readable storage, wherein the storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of any voltage balancing method provided in the embodiment of the present application.

[0085] The preferred embodiments of the present application are described above with reference to the accompanying drawings, but the scope of the present application is not limited thereby. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present application shall be within the scope of the present application.

Claims

1. A voltage balancing method, characterized in that: Applied to a control circuit, the control circuit is connected to a rectifier circuit and is used to control the working mode of the rectifier circuit, a first input end of the rectifier circuit is connected to a first DC bus, a second input end of the rectifier circuit is connected to a second DC bus, an output end of the rectifier circuit is used to connect a load, a first end of a first bus capacitor is connected to the first DC bus, a second end of the first bus capacitor is connected to a neutral point of the rectifier circuit, a first end of a second bus capacitor is connected to the neutral point, and a second end of the second bus capacitor is connected to the second DC bus; the method comprises: Acquire a first voltage of the first bus capacitor and a second voltage of the second bus capacitor; Obtaining a voltage difference between the first voltage and the second voltage, and obtaining difference change information corresponding to the voltage difference; The working mode of the rectifier circuit is confirmed according to the voltage difference and the difference change information, so as to balance the voltage of the neutral point.

2. The method according to claim 1, characterized in that The working mode includes a first working mode and a second working mode, the first working mode is used to charge the first bus capacitor, and the second working mode is used to charge the second bus capacitor; when the working mode of the rectifier circuit is the first working mode, confirming the working mode of the rectifier circuit according to the voltage difference and the difference change information includes: Whether it is necessary to switch the working mode of the rectifier circuit from the first working mode to the second working mode is confirmed based on the voltage difference and the difference change information; wherein, if the difference change information is getting larger and larger and the voltage difference is a positive number, or, the difference change information is getting smaller and smaller and the voltage difference is a negative number, it is confirmed that the working mode of the rectifier circuit needs to be switched from the first working mode to the second working mode.

3. The method according to claim 1, characterized in that The step of confirming the working mode of the rectifier circuit according to the voltage difference and the difference change information includes: Binarizing the voltage difference to obtain a first binarization result, and binarizing the difference change information to obtain a second binarization result; The operating mode of the rectifier circuit is determined according to the product of the first binarization result and the second binarization result.

4. The method according to claim 3, characterized in that The binarization of the voltage difference to obtain a first binarization result, and the binarization of the difference change information to obtain a second binarization result, include: When the voltage difference is a positive number, the first binarization result is assigned a first value, and when the voltage difference is a negative number, the first binarization result is assigned a second value; When the difference change information indicates that the absolute value of the voltage difference increases, the second binarization result is assigned the second value; when the absolute value of the voltage difference decreases, the second binarization result is assigned the first value; wherein the first value is a positive number and the second value is a negative number.

5. The method according to claim 4, characterized in that The working mode includes a first working mode and a second working mode, the first working mode is used to charge the first bus capacitor, and the second working mode is used to charge the first bus capacitor; when the working mode of the rectifier circuit is the first working mode, determining the working mode of the rectifier circuit according to the product of the first binarization result and the second binarization result includes: If the second binarization result is a negative number, generating request information, wherein the request information is used to request to switch the working mode of the rectifier circuit from the first working mode to the second working mode; If the product is a negative number, the request information is executed.

6. The method according to claim 2, characterized in that The rectifier circuit includes a first switch unit and a second switch unit, wherein a first end of the first switch unit is connected to a first end of a preset power supply, a second end of the first switch unit is connected to the first DC bus, a control end of the first switch unit is connected to the control circuit, a first end of the second switch unit is connected to a first end of the preset power supply, a second end of the second switch unit is connected to the second DC bus, a control end of the second switch unit is connected to the control circuit, and a second end of the preset power supply is connected to the neutral point; the method includes: generating a first control signal, wherein the first control signal is used to control the first switch unit to be turned on and the second switch unit to be turned off, so that the rectifier circuit is in a first working mode; A second control signal is generated, where the second control signal is used to control the second switch unit to be turned on and the first switch unit to be turned off, so that the rectifier circuit is in a second working mode.

7. The method according to claim 1, characterized in that The obtaining a first voltage of the first bus capacitor and a second voltage of the second bus capacitor includes: Sampling is performed according to twice the switching cycle to obtain multiple first voltages and second voltages; wherein the switching cycle is the time interval between the current update and the next update pulse of the pulse width modulation signal output by a preset power supply connected to the input end of the rectifier circuit.

8. A voltage balancing circuit, characterized in that: The invention comprises a rectifier circuit and a control circuit, wherein the control circuit is connected to the rectifier circuit and is used to control the working mode of the rectifier circuit, a first input end of the rectifier circuit is connected to a first DC bus, a second input end of the rectifier circuit is connected to a second DC bus, an output end of the rectifier circuit is used to connect a load, a first end of a first bus capacitor is connected to the first DC bus, a second end of the first bus capacitor is connected to a neutral point of the rectifier circuit, a first end of a second bus capacitor is connected to the neutral point, and a second end of the second bus capacitor is connected to the second DC bus; Wherein, the control circuit implements the steps of the voltage balancing method according to any one of claims 1 to 7.

9. An electronic device, characterized in that: Comprising the voltage balancing circuit as claimed in claim 8.

10. A storage medium for computer-readable storage, characterized in that: The storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps of the voltage balancing method according to any one of claims 1 to 7.

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