Neutral point balance control method and device for wind power converter
By obtaining the DC bus voltage imbalance and turning on the midpoint balance control strategy, the problem of midpoint potential imbalance in the DC bus in the three-level inverter is solved, and more precise control is achieved, equipment damage and current harmonics are reduced, and control algorithms and hardware implementations are simplified.
Patent Information
- Application Number
- CN202411994805.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-08
AI Technical Summary
During operation, a three-level inverter needs to continue to pay attention to the balance of the midpoint potential of the DC bus. The imbalance of the midpoint potential will lead to device damage, system efficiency decline and harmonics of the output current, affecting system stability and power quality.
By obtaining the voltage imbalance between the upper and lower capacitors of the DC bus, and according to the preset imbalance threshold response, the mid-point balance control strategy is used to obtain the upper and lower limits of the current carrier period and mid-point current value, and perform mid-point balance control.
Accurately determine the mid-point balance control strategy to avoid uncertainty caused by traditional empirical judgments, reduce equipment damage and current harmonics caused by mid-point potential imbalance, simplify the implementation of control algorithms, and reduce hardware complexity.
Smart Images
Figure CN119787777A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power generation technology, and in particular to a midpoint balancing control method and device for a wind power converter. Background Art
[0002] With the rapid development of wind power generation technology, high-power wind power converters are increasingly used in wind farms. The three-level converter has become one of the mainstream topologies of wind power converters due to its high power handling capability and low harmonic distortion. However, in actual operation, the three-level inverter needs to pay continuous attention to the balance of the DC bus midpoint potential. Unbalanced midpoint potential will increase the voltage stress of the switching device, which will cause device damage and reduce system efficiency. In addition, unbalanced midpoint potential will also cause harmonics in the output current, thus affecting the stability and power quality of the system.
[0003] In order to ensure the safe and efficient operation of the three-level inverter, midpoint potential balance control is one of its core technologies. The implementation of midpoint balance control usually relies on switching operation, and the accuracy of switching timing directly affects the performance and stability of the system. If the switching operation is too late, it may cause an imbalance in the upper and lower DC bus voltages, thereby causing overvoltage shock to the power switch devices and even damage to the devices; if the switching operation is too early, it may cause misoperation and cause the control system to over-respond, which not only wastes computing resources and control bandwidth, but also may affect the dynamic response and stability of the inverter. Summary of the invention
[0004] The present application aims to solve one of the technical problems in the related art at least to some extent.
[0005] To this end, one purpose of the present application is to propose a midpoint balancing control method for a wind power converter, by obtaining the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between the machine-side converter and the grid-side converter; obtaining a preset imbalance threshold; and switching on a midpoint balancing control strategy in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold.
[0006] The second objective of the present application is to provide a midpoint balancing control device for a wind power converter.
[0007] The third objective of the present application is to provide an electronic device.
[0008] A fourth object of the present application is to provide a non-transitory computer-readable storage medium.
[0009] A fifth object of the present application is to provide a computer program product.
[0010] To achieve the above-mentioned purpose, the first aspect embodiment of the present application proposes a midpoint balancing control method for a wind power converter, including: obtaining the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between the machine-side converter and the grid-side converter; obtaining a preset imbalance threshold; in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, switching on a midpoint balancing control strategy.
[0011] According to one embodiment of the present application, obtaining the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus includes: obtaining a first voltage of the capacitor on the DC bus, and obtaining a second voltage of the capacitor under the DC bus; obtaining the difference between the first voltage and the second voltage; obtaining the sum of the first voltage and the second voltage; and using the ratio of the difference to the sum as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
[0012] According to one embodiment of the present application, in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, a midpoint balance control strategy is switched on, including: in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, obtaining the current carrier cycle; obtaining the upper and lower limits of the midpoint current values of the capacitors on the DC bus and the capacitors under the DC bus corresponding to the current carrier cycle; and performing midpoint balance control according to the upper and lower limits of the midpoint current values.
[0013] According to one embodiment of the present application, the formula for obtaining the upper and lower limits of the midpoint current value of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle is:
[0014]
[0015] In the above formula, I np_ip Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; C indicates the capacitance value of the capacitor on the DC bus or the capacitance value of the capacitor under the DC bus. The capacitance value of the capacitor on the DC bus is equal to the capacitance value of the capacitor under the DC bus; V dc represents the sum of the first voltage of the capacitor on the DC bus and the second voltage of the capacitor under the DC bus; δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus; δ * represents the imbalance threshold; T s Indicates the current carrier cycle.
[0016] According to one embodiment of the present application, midpoint balance control is performed according to the upper and lower limits of the midpoint current value, including:
[0017] After the midpoint balance control is completed, the midpoint current value satisfies the following formula:
[0018] Inp_down ≤I * np ≤I np_up
[0019] In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; Indicates the real-time midpoint current value.
[0020] To achieve the above-mentioned purpose, the second aspect of the present application proposes a midpoint balance control device for a wind power converter, including: a first acquisition module, used to obtain the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between the machine-side converter and the grid-side converter; a second acquisition module, used to obtain a preset imbalance threshold; and a switching module, used to switch on a midpoint balance control strategy in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold.
[0021] According to one embodiment of the present application, the first acquisition module is also used to: obtain a first voltage of the capacitor on the DC bus, and obtain a second voltage of the capacitor under the DC bus; obtain the difference between the first voltage and the second voltage; obtain the sum of the first voltage and the second voltage; and use the ratio of the difference to the sum as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
[0022] According to one embodiment of the present application, the switching module is also used to: obtain the current carrier cycle in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold; obtain the upper and lower limits of the midpoint current values of the capacitors on the DC bus and the capacitors under the DC bus corresponding to the current carrier cycle; and perform midpoint balance control according to the upper and lower limits of the midpoint current value.
[0023] According to one embodiment of the present application, the formula for obtaining the upper and lower limits of the midpoint current values of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle in the switching module is:
[0024]
[0025] In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; C indicates the capacitance value of the capacitor on the DC bus or the capacitance value of the capacitor under the DC bus. The capacitance value of the capacitor on the DC bus is equal to the capacitance value of the capacitor under the DC bus; V dc represents the sum of the first voltage of the capacitor on the DC bus and the second voltage of the capacitor under the DC bus; δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus; δ * represents the imbalance threshold; Ts Indicates the current carrier cycle.
[0026] According to one embodiment of the present application, after the midpoint balancing control is completed in the switching module, the midpoint current value satisfies the following formula:
[0027] I np_down ≤I * np ≤I np_up
[0028] In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; Indicates the real-time midpoint current value.
[0029] To achieve the above-mentioned purpose, the third aspect embodiment of the present application proposes an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to implement the midpoint balancing control method of the wind power converter as described in the first aspect embodiment of the present application.
[0030] To achieve the above-mentioned purpose, the fourth aspect embodiment of the present application proposes a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to implement the midpoint balancing control method of the wind power converter as described in the first aspect embodiment of the present application.
[0031] To achieve the above-mentioned purpose, the fifth aspect of the present application proposes a computer program product, including a computer program, which, when executed by a processor, implements the midpoint balancing control method of the wind power converter as described in the first aspect of the present application.
[0032] The present application achieves at least the following beneficial effects: the present application can accurately determine when to switch on the midpoint balance control strategy based on the real-time measured voltage imbalance and the preset imbalance threshold, thereby avoiding the uncertainty brought about by traditional empirical judgment and effectively reducing equipment damage and current harmonics caused by midpoint potential imbalance; and, the present solution is based on clear mathematical formulas and can be directly converted into a digital control program, which simplifies the implementation of the control algorithm, reduces the complexity of hardware implementation, and has strong practicality and scalability. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:
[0034] Figure 1It is a schematic diagram of an exemplary implementation of a midpoint balancing control method for a wind power converter shown in an embodiment of the present application.
[0035] Figure 2 It is a schematic diagram of the positions of capacitors on a DC bus and capacitors under a DC bus, shown in one embodiment of the present application.
[0036] Figure 3 It is a schematic diagram of an exemplary implementation of a midpoint balancing control method for a wind power converter shown in an embodiment of the present application.
[0037] Figure 4 It is a schematic diagram of a midpoint balancing control device for a wind power converter shown in one embodiment of the present application.
[0038] Figure 5 It is a schematic diagram of an electronic device shown in one embodiment of the present application. DETAILED DESCRIPTION
[0039] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.
[0040] Figure 1 is a schematic diagram of an exemplary implementation of a midpoint balancing control method for a wind power converter shown in the present application, such as Figure 1 As shown, the midpoint balance control method of the wind power converter includes the following steps:
[0041] S101, obtaining a voltage imbalance between a capacitor on a DC bus and a capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between a machine-side converter and a grid-side converter.
[0042] Figure 2 Schematic diagram of the positions of capacitors on a DC bus and capacitors under a DC bus shown in the present application, such as Figure 2 As shown, electric energy is output from the machine-side converter 101 to the input end of the DC bus capacitor 102 , and then output from the DC bus capacitor 102 to the input end of the grid-side converter 103 .
[0043] The DC bus capacitor 102 includes an upper DC bus capacitor and a lower DC bus capacitor.
[0044] Among them, the voltage imbalance between the capacitors on the DC bus and the capacitors under the DC bus reflects the degree of voltage difference between the capacitors.
[0045] S102: Obtain a preset imbalance threshold.
[0046] The unbalance threshold is used to determine whether the voltage unbalance between the capacitor on the DC bus and the capacitor under the DC bus exceeds a normal range.
[0047] The imbalance threshold may be set according to design parameters, working conditions and performance requirements of the wind power converter.
[0048] S103, in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, switching to a midpoint balancing control strategy.
[0049] The voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus is denoted as δ; the preset imbalance threshold is denoted as δ * .
[0050] When |δ|≥δ * When , the midpoint balance control strategy is adopted.
[0051] When |δ|<δ * When , the midpoint balance control strategy is not implemented.
[0052] The embodiment of the present application proposes a midpoint balance control method for a wind power converter, including: obtaining the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between the machine-side converter and the grid-side converter; obtaining a preset imbalance threshold; in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, switching on the midpoint balance control strategy. The present application can accurately determine when to switch on the midpoint balance control strategy based on the real-time measured voltage imbalance and the preset imbalance threshold, avoiding the uncertainty caused by traditional empirical judgment, and effectively reducing equipment damage and current harmonics caused by midpoint potential imbalance; and, the present solution is based on a clear mathematical formula and can be directly converted into a digital control program, which simplifies the implementation of the control algorithm, reduces the complexity of hardware implementation, and has strong practicality and scalability.
[0053] Figure 3 is a schematic diagram of an exemplary implementation of a midpoint balancing control method for a wind power converter shown in the present application, such as Figure 3 As shown, the midpoint balance control method of the wind power converter includes the following steps:
[0054] S301, obtaining a first voltage of a capacitor on a DC bus, and obtaining a second voltage of a capacitor under a DC bus.
[0055] Get the first voltage V of the capacitor on the DC bus dc1 .
[0056] Get the second voltage V of the capacitor under the DC bus dc2 .
[0057] S302: Obtain a difference between the first voltage and the second voltage.
[0058] Get the first voltage V dc1 and the second voltage V dc2 The difference is: V dc1 -V dc2 .
[0059] S303: Obtain a sum of the first voltage and the second voltage.
[0060] Get the first voltage V dc1 and the second voltage V dc2 The sum of is: V dc1 +V dc2 .
[0061] S304, taking the ratio of the difference value to the sum value as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
[0062]
[0063] In the above formula, V dc1 Represents the first voltage of the capacitor on the DC bus; V dc2 represents the second voltage of the capacitor under the DC bus; δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
[0064] S305: Obtain a preset imbalance threshold.
[0065] S306: In response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, switching to a midpoint balancing control strategy.
[0066] If the absolute value of the imbalance is greater than or equal to the imbalance threshold, obtain the current carrier cycle; obtain the upper and lower limits of the midpoint current values of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle; perform midpoint balance control according to the upper and lower limits of the midpoint current value.
[0067] The formula for obtaining the upper and lower limits of the midpoint current values of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle is:
[0068]
[0069] In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_downIndicates the lower limit of the midpoint current value; C indicates the capacitance value of the capacitor on the DC bus or the capacitance value of the capacitor under the DC bus. The capacitance value of the capacitor on the DC bus is equal to the capacitance value of the capacitor under the DC bus; V dc represents the sum of the first voltage of the capacitor on the DC bus and the second voltage of the capacitor under the DC bus, that is, V dc =V dc1 +V dc2 ;δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus;δ * represents the imbalance threshold; T s Indicates the current carrier cycle.
[0070] Among them, after the midpoint balance control is completed, the midpoint current value should satisfy the following formula:
[0071] I np_down ≤I * np ≤I np_up
[0072] In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; Indicates the real-time midpoint current value.
[0073] The embodiment of the present application can accurately determine when to switch on the midpoint balance control strategy based on the real-time measured voltage imbalance and the preset imbalance threshold, thereby avoiding the uncertainty brought by traditional empirical judgment and effectively reducing equipment damage and current harmonics caused by midpoint potential imbalance.
[0074] Figure 4 is a schematic diagram of a midpoint balancing control device for a wind power converter shown in the present application, such as Figure 4 As shown, the midpoint balance control device 400 of the wind power converter includes a first acquisition module 401, a second acquisition module 402 and a switching module 403, wherein:
[0075] The first acquisition module 401 is used to acquire the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between the machine-side converter and the grid-side converter.
[0076] The second acquisition module 402 is used to acquire a preset imbalance threshold.
[0077] The switching module 403 is used to switch the midpoint balance control strategy in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold.
[0078] This device can accurately determine when to switch on the midpoint balance control strategy based on the real-time measured voltage imbalance and the preset imbalance threshold, avoiding the uncertainty brought by traditional empirical judgment and effectively reducing equipment damage and current harmonics caused by midpoint potential imbalance; moreover, this solution is based on clear mathematical formulas and can be directly converted into a digital control program, which simplifies the implementation of the control algorithm, reduces the complexity of hardware implementation, and has strong practicality and scalability.
[0079] Furthermore, the first acquisition module 401 is also used to: obtain a first voltage of the capacitor on the DC bus, and obtain a second voltage of the capacitor under the DC bus; obtain the difference between the first voltage and the second voltage; obtain the sum of the first voltage and the second voltage; and use the ratio of the difference to the sum as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
[0080] Furthermore, the switching module 403 is also used to: obtain the current carrier cycle in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold; obtain the upper and lower limits of the midpoint current value corresponding to the capacitor on the DC bus and the capacitor under the DC bus in the current carrier cycle; and perform midpoint balance control according to the upper and lower limits of the midpoint current value.
[0081] Furthermore, the formula for obtaining the upper and lower limits of the midpoint current values of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle in the switching module 403 is:
[0082]
[0083] In the above formula, I np_up Indicates the upper limit of the midpoint current value; i np_down Indicates the lower limit of the midpoint current value; C indicates the capacitance value of the capacitor on the DC bus or the capacitance value of the capacitor under the DC bus. The capacitance value of the capacitor on the DC bus is equal to the capacitance value of the capacitor under the DC bus; V dc represents the sum of the first voltage of the capacitor on the DC bus and the second voltage of the capacitor under the DC bus; δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus; δ * represents the imbalance threshold; T s Indicates the current carrier cycle.
[0084] Furthermore, after the midpoint balance control is completed in the switching module 403, the midpoint current value satisfies the following formula:
[0085] I np_down ≤I * np ≤I np_up
[0086] In the above formula, i np_upIndicates the upper limit of the midpoint current value; i np_down Indicates the lower limit of the midpoint current value; Indicates the real-time midpoint current value.
[0087] In order to implement the above embodiment, the present application embodiment also proposes an electronic device 500, such as Figure 5 As shown, the electronic device 500 includes: a processor 501 and a memory 502 that is communicatively connected to the processor, the memory 502 stores instructions that can be executed by at least one processor, and the instructions are executed by at least one processor 501 to implement the midpoint balance control method of the wind power converter as shown in the above embodiment.
[0088] In order to implement the above embodiment, the embodiment of the present application further proposes a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable a computer to implement the midpoint balancing control method of a wind power converter as shown in the above embodiment.
[0089] In order to implement the above embodiments, the embodiments of the present application further provide a computer program product, including a computer program. When the computer program is executed by a processor, the midpoint balancing control method of the wind power converter as shown in the above embodiments is implemented.
[0090] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0091] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0092] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0093] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.
Claims
1. A midpoint balance control method for a wind power converter, characterized in that: include: Obtaining a voltage imbalance between a capacitor on a DC bus and a capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between a machine-side converter and a grid-side converter; Get the preset imbalance threshold; In response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, a midpoint balancing control strategy is switched on.
2. The method according to claim 1, characterized in that The step of obtaining the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus includes: Acquire a first voltage of a capacitor on the DC bus, and acquire a second voltage of a capacitor under the DC bus; obtaining a difference between the first voltage and the second voltage; Obtaining a sum of the first voltage and the second voltage; The ratio of the difference to the sum is used as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
3. The method according to claim 2, characterized in that In response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, switching on the midpoint balance control strategy comprises: In response to the absolute value of the imbalance being greater than or equal to the imbalance threshold, acquiring a current carrier cycle; Obtain upper and lower limits of midpoint current values of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle; The midpoint balance control is performed according to the upper and lower limits of the midpoint current value.
4. The method according to claim 3, characterized in that The formula for obtaining the upper and lower limits of the midpoint current value of the capacitor on the DC bus and the capacitor under the DC bus corresponding to the current carrier cycle is: In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down represents the lower limit of the midpoint current value; C represents the capacitance value of the capacitor on the DC bus or the capacitance value of the capacitor under the DC bus, and the capacitance value of the capacitor on the DC bus is equal to the capacitance value of the capacitor under the DC bus; V dc represents the sum of the first voltage of the capacitor on the DC bus and the second voltage of the capacitor under the DC bus; δ represents the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus; δ * represents the imbalance threshold; T s Indicates the current carrier cycle.
5. The method according to claim 4, characterized in that The midpoint balance control is performed according to the upper and lower limits of the midpoint current value, including: After the midpoint balance control is completed, the midpoint current value satisfies the following formula: In the above formula, I np_up Indicates the upper limit of the midpoint current value; I np_down Indicates the lower limit of the midpoint current value; Indicates the real-time midpoint current value.
6. A midpoint balance control device for a wind power converter, characterized in that: include: A first acquisition module is used to acquire a voltage imbalance between a capacitor on a DC bus and a capacitor under the DC bus, wherein the capacitor on the DC bus and the capacitor under the DC bus are located between a machine-side converter and a grid-side converter; A second acquisition module is used to acquire a preset imbalance threshold; The switching module is used to switch the midpoint balance control strategy in response to the absolute value of the imbalance being greater than or equal to the imbalance threshold.
7. The device according to claim 6, characterized in that The first acquisition module is further used for: Acquire a first voltage of a capacitor on the DC bus, and acquire a second voltage of a capacitor under the DC bus; obtaining a difference between the first voltage and the second voltage; Obtaining a sum of the first voltage and the second voltage; The ratio of the difference to the sum is used as the voltage imbalance between the capacitor on the DC bus and the capacitor under the DC bus.
8. An electronic device comprising: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 5.
9. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-5.
10. A computer program product comprising a computer program, which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 5.