A control method, device and apparatus for a three-phase four-leg inverter

Abstract

The present application discloses a control method, device, equipment, and readable storage medium for a three-phase four-bridge-arm inverter, relating to the field of power electronics technology. The method comprises: determining a three-phase reference voltage of the three-phase four-bridge-arm inverter in a three-phase stationary coordinate system based on the topological structure of the three-phase four-bridge-arm inverter; calculating an output voltage function of the three-phase four-bridge-arm inverter based on the three-phase reference voltage; the output voltage function includes a saturation function gain and a sliding surface adaptive weight coefficient; calculating the saturation function gain and the sliding surface adaptive weight coefficient using a sigmoid function; substituting the saturation function gain and the sliding surface adaptive weight coefficient into the output voltage function to obtain a target output voltage of the three-phase four-bridge-arm inverter. The above method can improve dynamic performance while maintaining system stability and robustness.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a control method, device, equipment and readable storage medium for a three-phase four-leg inverter. Background Art

[0002] Multilevel inverters have seen rapid development in recent years due to their advantages, including high output voltage quality, minimal electromagnetic interference, and low harmonic content. For example, the three-phase, four-leg inverter topology, with its ability to independently adjust zero-sequence voltage, exhibits improved control performance under complex operating conditions such as unbalanced loads and grid disturbances, and has become a research hotspot.

[0003] However, this structure also introduces additional control freedom and complexity. While some traditional control methods, such as the PI dual-closed-loop control strategy, can achieve stable control of three-phase output voltage and current, they also suffer from issues such as poor capacity for unbalanced and nonlinear loads, high output voltage harmonic content, and poor system dynamic and steady-state performance. While model predictive control strategies have improved inverter performance to a certain extent, they carry a heavy computational burden and are prone to large steady-state errors when faced with load disturbances and grid fluctuations. Sliding mode control, while gaining attention for its robustness, suffers from chattering issues under high-frequency switching.

[0004] Therefore, how to maintain system stability and robustness while improving dynamic performance is an urgent problem that needs to be solved in this field. Summary of the Invention

[0005] The object of the present invention is to provide a control method, device, equipment and readable storage medium for a three-phase four-bridge-leg inverter. The output voltage function of the three-phase four-bridge-leg inverter is predicted based on the three-phase reference voltage of the three-phase four-bridge-leg inverter in a three-phase stationary coordinate system, and the optimal saturation function gain of the output voltage function and the sliding surface adaptive weight coefficient are calculated using a sigmoid function. In this way, the target output voltage calculated based on the optimal saturation function gain and the sliding surface adaptive weight coefficient improves dynamic performance while maintaining system stability and robustness compared to direct voltage output.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a control method for a three-phase four-leg inverter, the method comprising:

[0008] Based on the topology of the three-phase four-leg inverter, the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system is determined;

[0009] Based on the three-phase reference voltage, calculating the output voltage function of the three-phase four-leg inverter; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient;

[0010] Calculating the saturation function gain and the sliding surface adaptive weight coefficient using a sigmoid function;

[0011] The saturation function gain and the sliding mode surface adaptive weight coefficient are substituted into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

[0012] In some embodiments, calculating the output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage includes:

[0013] constructing a predicted sliding mode surface based on the three-phase reference voltage;

[0014] An output voltage function of the three-phase four-leg inverter is solved according to a derivative of the predicted sliding mode surface.

[0015] In some embodiments, solving the output voltage function of the three-phase four-leg inverter according to the derivative of the predicted sliding mode surface includes:

[0016] According to the predicted sliding surface, solving the derivative of the predicted sliding surface using a discretized equation and a linear difference;

[0017] The derivative of the predicted sliding mode surface is set to 0, and the target output voltage function of the three-phase four-leg inverter is obtained by solving the problem.

[0018] In some embodiments, calculating the saturation function gain and the sliding surface adaptive weight coefficient using a sigmoid function includes:

[0019] Set the initial function gain and initial adaptive weight coefficient;

[0020] Smoothing the initial function gain using a sigmoid function to obtain the saturated function gain;

[0021] Determining a load voltage error of the three-phase four-leg inverter;

[0022] The sliding surface adaptive weight coefficient is calculated using a sigmoid function according to the initial adaptive weight coefficient and the load voltage error.

[0023] In some embodiments, determining a three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system based on a topology of the three-phase four-leg inverter includes:

[0024] Determining a current-voltage relationship between an output voltage and an output current of a three-phase four-leg inverter based on a topological structure of the three-phase four-leg inverter;

[0025] According to the current-voltage relationship, Kirchhoff's law and Clarke transformation are used to obtain the three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system.

[0026] In some embodiments, the method further comprises:

[0027] An N-phase voltage of the three-phase four-leg inverter is calculated according to a target output voltage of the three-phase four-leg inverter.

[0028] In a second aspect, the present invention further provides a control device for a three-phase four-leg inverter, the device comprising:

[0029] A voltage determination module is used to determine a three-phase reference voltage of the three-phase four-bridge-leg inverter in a three-phase stationary coordinate system based on the topology of the three-phase four-bridge-leg inverter;

[0030] A function calculation module, configured to calculate an output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient;

[0031] A coefficient solving module, used for calculating the saturation function gain and the sliding surface adaptive weight coefficient using a sigmoid function;

[0032] A voltage control module is used to substitute the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

[0033] In a third aspect, the present invention further provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the control method of the three-phase four-leg inverter provided in the first aspect is implemented.

[0034] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the control method of the three-phase four-leg inverter provided in the first aspect is implemented.

[0035] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the control method of the three-phase four-leg inverter provided in the first aspect.

[0036] The beneficial effects of the present invention are:

[0037] The present invention provides a control method for a three-phase four-leg inverter. The method includes first determining a three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system based on the topology of the three-phase four-leg inverter. Then, based on the three-phase reference voltage, calculating an output voltage function of the three-phase four-leg inverter. The output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient. Then, the saturation function gain and the sliding mode surface adaptive weight coefficient are calculated using a sigmoid function. Finally, the saturation function gain and the sliding mode surface adaptive weight coefficient are substituted into the output voltage function to obtain a target output voltage of the three-phase four-leg inverter. The output voltage function of the three-phase four-leg inverter is predicted based on the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system. The optimal saturation function gain and the sliding mode surface adaptive weight coefficient of the output voltage function are calculated using a sigmoid function. Compared with direct voltage output, the target output voltage calculated based on the optimal saturation function gain and the sliding mode surface adaptive weight coefficient improves dynamic performance while maintaining system stability and robustness.

[0038] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a flow chart of a control method for a three-phase four-leg inverter according to an embodiment of the present invention;

[0040] Figure 2 1 is a diagram showing output voltage and current waveforms of a three-phase four-leg inverter under a linear load and a control method of a three-phase four-leg inverter in this application according to an embodiment of the present invention;

[0041] Figure 3 The total harmonic distortion of the three-phase four-leg inverter under the condition of linear load as shown in one embodiment of the present invention and the control method of the three-phase four-leg inverter in this application;

[0042] Figure 4 1 is a diagram showing output voltage and current waveforms of a three-phase four-leg inverter under a linear load and a conventional three-phase four-leg inverter control method according to an embodiment of the present invention;

[0043] Figure 5 Total harmonic distortion of a three-phase four-leg inverter under a linear load and a conventional three-phase four-leg inverter control method according to an embodiment of the present invention;

[0044] Figure 6 1 is a diagram showing output voltage and current waveforms of a three-phase four-leg inverter under a nonlinear load and a control method of a three-phase four-leg inverter in this application according to an embodiment of the present invention;

[0045] Figure 7 Total harmonic distortion of a three-phase four-leg inverter under a nonlinear load as shown in one embodiment of the present invention and a control method of a three-phase four-leg inverter in this application;

[0046] Figure 8 1 is a diagram showing output voltage and current waveforms of a three-phase four-leg inverter under a nonlinear load and a conventional three-phase four-leg inverter control method according to an embodiment of the present invention;

[0047] Figure 9 Total harmonic distortion of a three-phase four-leg inverter under a nonlinear load and a conventional three-phase four-leg inverter control method according to an embodiment of the present invention;

[0048] Figure 10 This is a dynamic effect diagram of load switching under a traditional three-phase four-leg inverter control method shown in one embodiment of the present invention;

[0049] Figure 11 This is a dynamic effect diagram of load switching under the control method of the three-phase four-leg inverter in this application shown in one embodiment of the present invention;

[0050] Figure 12 1 is a flow chart of another control method for a three-phase four-leg inverter according to an embodiment of the present invention;

[0051] Figure 13 Schematic diagram of the structure of a control device for a three-phase four-leg inverter according to an embodiment of the present invention;

[0052] Figure 14 Schematic diagram of the structure of another control device for a three-phase four-leg inverter according to an embodiment of the present invention;

[0053] Figure 15 A schematic diagram of the structure of an electronic device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0054] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0055] It should be noted that references to "one embodiment," "an embodiment," "an example embodiment," etc., in this specification indicate that the embodiment being described may include specific features, structures, or characteristics. However, not every embodiment must include these specific features, structures, or characteristics. In addition, such references do not necessarily refer to the same embodiment. Furthermore, when specific features, structures, or characteristics are described in conjunction with an embodiment, whether or not they are explicitly described, it is indicated that incorporating such features, structures, or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0056] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] In some embodiments, as Figure 1 As shown, a control method for a three-phase four-leg inverter is provided, and the specific method includes:

[0058] S101 , based on a topology structure of a three-phase four-leg inverter, determining a three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system.

[0059] Specifically, the relationship between the output voltage and output current of the three-phase four-bridge-arm inverter can be extracted from the topology structure of the three-phase four-bridge-arm inverter, and then the relationship between the output voltage and output current can be converted into a three-phase stationary coordinate system through coordinate system transformation to obtain the three-phase reference voltage of the three-phase four-bridge-arm inverter.

[0060] Optionally, the method for obtaining the three-phase reference voltage of the three-phase four-bridge-arm inverter in the three-phase stationary coordinate system can also be: based on the topological structure of the three-phase four-bridge-arm inverter, determine the current-voltage relationship between the output voltage and output current of the three-phase four-bridge-arm inverter; according to the current-voltage relationship, use Kirchhoff's law and Clarke transformation to obtain the three-phase reference voltage of the three-phase four-bridge-arm inverter in the three-phase stationary coordinate system.

[0061] Exemplarily, based on the topology of a three-phase four-leg inverter, the current-voltage relationship between the output voltage and the output current of the three-phase four-leg inverter is determined as follows:

[0062] ;

[0063] ;

[0064] in, , , is the output voltage, , , , is the output current, , , is the load voltage, , , is the load current, L is the filter inductor, C is the filter capacitor, Ln is the filter capacitor of the fourth bridge arm, and R is the line impedance.

[0065] Kirchhoff's law can be used to obtain the following formula (3):

[0066] ;

[0067] in, , , , is the output current.

[0068] Substituting the above formula (3) into the above formula (1) yields the following formula (4):

[0069] ;

[0070] in, , , is the output voltage of the three-phase four-leg inverter, , , , is the output current of the three-phase four-leg inverter, , , is the load voltage of the three-phase four-leg inverter, Ln is the filter capacitor of the fourth leg, and R is the line impedance.

[0071] The mathematical model of the three-phase four-leg inverter is transformed into a three-phase stationary coordinate system through Clarke transformation, thereby increasing the computational efficiency. The formula of Clarke transformation is as follows (5):

[0072] ;

[0073] Clarke transformation is performed on the above formula (2) and the above formula (4) to obtain the following formulas (6)-(7):

[0074] ;

[0075] ;

[0076] in, , , and , , is the output current and load current of the three-phase four-leg inverter, , , is the load voltage of the three-phase four-leg inverter.

[0077] Therefore, the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system is , , It can be expressed as the following formula (8):

[0078] ;

[0079] in , are the voltage reference value and the angular frequency reference value, , , is the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system.

[0080] S102 , calculating an output voltage function of a three-phase four-leg inverter based on a three-phase reference voltage.

[0081] The output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient.

[0082] Specifically, a predicted sliding mode surface can be constructed based on the three-phase reference voltage; and the output voltage function of the three-phase four-leg inverter can be solved according to the derivative of the predicted sliding mode surface.

[0083] Optionally, the process of solving the output voltage function of the three-phase four-leg inverter based on the derivative of the predicted sliding surface can be: based on the predicted sliding surface, using discretized equations and linear differences to solve the derivative of the predicted sliding surface; setting the derivative of the predicted sliding surface to 0, and solving to obtain the target output voltage function of the three-phase four-leg inverter.

[0084] For example, the predicted sliding surface is first constructed as shown in formula (9):

[0085] ;

[0086] ;

[0087] in, and is the adaptive weight coefficient of the sliding surface, , , is the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system, To predict the sliding surface.

[0088] In order to obtain the inverter output voltage, it is necessary to make the derivative of the predicted sliding surface zero, as shown in formula (10):

[0089] ;

[0090] In order to obtain the derivative of the sliding surface, it is necessary to calculate the and and their first-order and second-order derivatives, by discretizing formulas (6) and (7), we can obtain the following formula (11):

[0091] ;

[0092] in, , , , , and , , is the output current and load current of the three-phase four-leg inverter, C is the filter capacitor, is the sampling period.

[0093] Since the sampling frequency is high enough, it can be assumed that the load current will not change suddenly within one cycle, so the following equation (12) is obtained:

[0094] ;

[0095] in, , , is the load current of the three-phase four-leg inverter.

[0096] Combining (11)-(12) we can express and its first-order derivative and second-order derivative, see the following formula (13):

[0097] ;

[0098] ;

[0099] in, is the sampling period, C is the filter capacitor, , , is the load voltage of the three-phase four-leg inverter, , , and , , are the output current and load current of the three-phase four-leg inverter.

[0100] Obtained by linear interpolation , refer to the following formulas (14)-(16):

[0101] ;

[0102] ;

[0103] ;

[0104] Through discretization, we can get The first-order and second-order derivatives of are as follows:

[0105] ;

[0106] Combining (13), (16) and (17), (10) can be expressed as the following formula (18):

[0107] ;

[0108] Where A is the polynomial of the load voltage reference.

[0109] By solving , we get the following formula (19):

[0110] ;

[0111] The predicted sliding surface at time k+2 is expressed by (13), (16) and (17) as follows (20):

[0112] ;

[0113] The saturation function is expressed as formula (21):

[0114] ;

[0115] in, is the saturation function boundary.

[0116] Finally, the output voltage function of the three-phase four-leg inverter is expressed as formula (22):

[0117] ;

[0118] in, is the saturation function gain.

[0119] S103: Calculate the saturation function gain and the sliding surface adaptive weight coefficient using the sigmoid function.

[0120] Specifically, an initial function gain and an initial adaptive weight coefficient can be set; the initial function gain is smoothed using a sigmoid function to obtain a saturated function gain; the load voltage error of the three-phase four-leg inverter is determined; and the sliding surface adaptive weight coefficient is calculated using a sigmoid function based on the initial adaptive weight coefficient and the load voltage error.

[0121] For example, due to the saturation function gain Directly affects the stability, convergence speed and chattering characteristics of the system. At the same time, the sliding surface adaptive weight coefficient and It will also affect the dynamic performance and steady-state performance of the system. Therefore, a reasonable choice , and The value of is crucial. The initial function gain can be adjusted based on the system disturbance and stability margin, combined with simulation research and experimental debugging. Set to 6, the initial adaptive weight coefficient Set to 8000. In order to reduce the system chattering, the sigmoid function is introduced for smoothing. It is expressed as the following formula (23):

[0122] ;

[0123] The load voltage error is expressed as follows (24):

[0124] ;

[0125] In order to achieve better dynamic and steady-state performance, the sigmoid function is introduced into the system. The final expression of is as follows:

[0126] ;

[0127] In order to ensure that the formula (19) The coefficient of is positive, so we can get The value range of is as follows:

[0128] ;

[0129] Setting the value of (26) to 1 / 2, we can The value of is expressed as the following formula (27):

[0130] ;

[0131] S104 , substituting the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

[0132] Specifically, the saturation function gain in the above formula (23) is , the sliding surface adaptive weight coefficient in formula (25) and the sliding surface adaptive weight coefficient in formula (27) , substituted into the above output voltage function formula (22), the target output voltage of the three-phase four-leg inverter can be obtained.

[0133] Optionally, after obtaining the target output voltage of the three-phase four-leg inverter, it is also possible to: calculate the N-phase voltage of the three-phase four-leg inverter according to the target output voltage of the three-phase four-leg inverter.

[0134] Among them, the N-phase voltage of the three-phase four-leg inverter can be expressed as the following formula (28):

[0135] ;

[0136] The control method for the three-phase four-leg inverter in the above embodiment first determines the three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system based on the topology of the three-phase four-leg inverter; then calculates the output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient; then calculates the saturation function gain and the sliding mode surface adaptive weight coefficient using a sigmoid function; and finally substitutes the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter. The output voltage function of the three-phase four-leg inverter is predicted based on the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system, and the optimal saturation function gain and the sliding mode surface adaptive weight coefficient of the output voltage function are calculated using a sigmoid function. Compared with directly outputting voltage, the target output voltage calculated based on the optimal saturation function gain and the sliding mode surface adaptive weight coefficient improves dynamic performance while maintaining system stability and robustness.

[0137] In another embodiment, the output optimization of the three-phase four-leg inverter under the control method of the three-phase four-leg inverter in this application is also demonstrated.

[0138] Figure 2 The output voltage and current waveforms of the three-phase four-leg inverter under the control method of the three-phase four-leg inverter in this application are shown in the figure (the upper half is the three-phase load voltage and the lower half is the A-phase load current) under the condition of linear load. In this case, the total harmonic distortion is 0.97% (see Figure 3 ); Figure 4 The output voltage and current waveforms of the three-phase four-leg inverter under the condition of linear load and the traditional three-phase four-leg inverter control method are shown in the figure (the upper half is the three-phase load voltage and the lower half is the A-phase load current). In this case, the total harmonic distortion is 1.16% (see Figure 5 ).

[0139] Figure 6 The output voltage and current waveforms of the three-phase four-leg inverter under the control method of the three-phase four-leg inverter in this application are shown in the figure (the upper half is the three-phase load voltage, and the lower half is the A-phase load current). In this case, the total harmonic distortion is 2.71% (see Figure 7 ); Figure 8 The output voltage and current waveforms of the three-phase four-leg inverter under the control method of the traditional three-phase four-leg inverter are shown in the figure (the upper half is the three-phase load voltage and the lower half is the A-phase load current) under the condition of nonlinear load. In this case, the total harmonic distortion is 3.86% (see Figure 9 ).

[0140] In summary, regardless of whether it is a linear load or a nonlinear load, the control method of the three-phase four-leg inverter in this application can effectively reduce the total harmonic distortion.

[0141] Figure 10 This is a diagram showing the dynamic effect of load switching under the control method of a traditional three-phase four-leg inverter. In this case, the recovery time of the half-bus voltage during dynamic load switching is 1.7s. Figure 11 This is a dynamic effect diagram of load switching under the control method of the three-phase four-leg inverter in this application. The recovery time of the half-bus voltage during dynamic load switching is 150ms. It can be seen that the control method of the three-phase four-leg inverter in this application effectively improves the dynamic performance of the three-phase four-leg inverter.

[0142] In order to more comprehensively demonstrate this solution, this embodiment provides an optional method for controlling a three-phase four-leg inverter, such as Figure 12 As shown:

[0143] S201 , based on the topology of the three-phase four-leg inverter, determine a current-voltage relationship between an output voltage and an output current of the three-phase four-leg inverter.

[0144] S202 , according to the current-voltage relationship, using Kirchhoff's law and Clarke transformation, obtain the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system.

[0145] S203: Construct a predicted sliding surface based on the three-phase reference voltage.

[0146] S204 , according to the predicted sliding surface, using a discretized equation and a linear difference to solve the derivative of the predicted sliding surface.

[0147] S205 , setting the derivative of the predicted sliding mode surface to 0, and solving to obtain the target output voltage function of the three-phase four-leg inverter.

[0148] The output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient.

[0149] S206: Setting the initial function gain and the initial adaptive weight coefficient.

[0150] S207 , smoothing the initial function gain using a sigmoid function to obtain a saturated function gain.

[0151] S208 , determining a load voltage error of the three-phase four-leg inverter.

[0152] S209 , calculating the sliding surface adaptive weight coefficient using a sigmoid function according to the initial adaptive weight coefficient and the load voltage error.

[0153] S210 , substituting the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

[0154] S211 , calculating and obtaining an N-phase voltage of the three-phase four-leg inverter according to the target output voltage of the three-phase four-leg inverter.

[0155] The specific process of the above S201-S211 can be found in the description of the above method embodiment. The implementation principle and technical effects are similar and will not be repeated here.

[0156] Based on the same inventive concept, embodiments of the present application further provide a control device for a three-phase four-leg inverter for implementing the control method for the three-phase four-leg inverter involved above. The implementation solution provided by this device is similar to the implementation solution described in the above method. Therefore, the specific limitations of one or more embodiments of the control device for a three-phase four-leg inverter provided below can be found in the limitations of the control method for the three-phase four-leg inverter described above and will not be repeated here.

[0157] In one embodiment, Figure 13 As shown, a control device for a three-phase four-leg inverter is provided, the device comprising:

[0158] A voltage determination module 30 is configured to determine a three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system based on a topology of the three-phase four-leg inverter;

[0159] A function calculation module 31 is configured to calculate an output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient;

[0160] A coefficient solving module 32 is used to calculate the saturation function gain and the sliding surface adaptive weight coefficient using a sigmoid function;

[0161] The voltage control module 33 is configured to substitute the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain a target output voltage of the three-phase four-leg inverter.

[0162] In another embodiment, Figure 14 As shown above Figure 13 The function calculation module 31 includes:

[0163] A sliding mode construction unit 310 is configured to construct a predicted sliding mode surface based on the three-phase reference voltage;

[0164] The function solving unit 311 is configured to solve the output voltage function of the three-phase four-leg inverter according to the derivative of the predicted sliding mode surface.

[0165] In another embodiment, the above Figure 14 The function solving unit 311 in is specifically used to: solve the derivative of the predicted sliding surface using a discretized equation and a linear difference according to the predicted sliding surface; set the derivative of the predicted sliding surface to 0, and solve to obtain the target output voltage function of the three-phase four-leg inverter.

[0166] In another embodiment, the above Figure 13 The coefficient solving module 32 is specifically used to: set the initial function gain and the initial adaptive weight coefficient; use the sigmoid function to smooth the initial function gain to obtain the saturated function gain; determine the load voltage error of the three-phase four-leg inverter; and use the sigmoid function to calculate the sliding surface adaptive weight coefficient based on the initial adaptive weight coefficient and the load voltage error.

[0167] In another embodiment, the above Figure 13 The voltage determination module 30 is specifically used to: determine the current-voltage relationship between the output voltage and output current of the three-phase four-bridge-arm inverter based on the topological structure of the three-phase four-bridge-arm inverter; according to the current-voltage relationship, use Kirchhoff's law and Clarke transformation to obtain the three-phase reference voltage of the three-phase four-bridge-arm inverter in the three-phase stationary coordinate system.

[0168] In another embodiment, the above Figure 13The control device of the three-phase four-bridge-arm inverter is further specifically used to: calculate the N-phase voltage of the three-phase four-bridge-arm inverter according to the target output voltage of the three-phase four-bridge-arm inverter.

[0169] The present application also provides an electronic device, in some embodiments, referring to Figure 15 As shown, the electronic device 700 includes an input unit 710, a memory 720, a processor 730, and an output unit 740. The memory 720 stores program instructions that can be executed by the processor 730. The processor 730 calls the program instructions to execute the control method and / or technical solution of the three-phase four-leg inverter based on the above-mentioned embodiment. The electronic device 700 can be a mobile terminal device such as a mobile phone or a computer.

[0170] In addition, an embodiment of the present application further provides a computer-readable storage medium for storing a computer program for executing a control method for a three-phase four-bridge-arm inverter. For example, a computer program instruction, when executed by a computer, can call or provide a method and / or technical solution according to the present application through the operation of the computer. The program instructions for calling the method of the present application may be stored in a fixed or removable storage medium, and / or transmitted through a data stream in a broadcast or other signal-carrying medium and / or stored in a storage medium that operates according to the program instructions.

[0171] Obviously, those skilled in the art should understand that the modules or steps of the present application described above can be implemented using a general-purpose computing device. They can be concentrated on a single computing device or distributed across a network consisting of multiple computing devices. Alternatively, they can be implemented using program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. Thus, the present application is not limited to any specific combination of hardware and software.

[0172] The various technical features of the above embodiments can be arbitrarily integrated. To make the description concise, not all possible integrations of the various technical features in the above embodiments are described. However, as long as there is no contradiction in the integration of these technical features, they should be considered to be within the scope of this specification.

[0173] The above embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A control method for a three-phase four-leg inverter, characterized in that: The method comprises: Based on the topology of the three-phase four-leg inverter, the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system is determined; Based on the three-phase reference voltage, calculating the output voltage function of the three-phase four-leg inverter; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient; Setting an initial function gain and an initial adaptive weight coefficient; smoothing the initial function gain using a sigmoid function to obtain the saturation function gain; determining a load voltage error of the three-phase four-leg inverter; and calculating the sliding surface adaptive weight coefficient using a sigmoid function based on the initial adaptive weight coefficient and the load voltage error; The saturation function gain and the sliding mode surface adaptive weight coefficient are substituted into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

2. The control method of the three-phase four-leg inverter according to claim 1, wherein: Calculating an output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage includes: constructing a predicted sliding mode surface based on the three-phase reference voltage; An output voltage function of the three-phase four-leg inverter is solved according to a derivative of the predicted sliding mode surface.

3. The control method of the three-phase four-leg inverter according to claim 2, wherein: Solving the output voltage function of the three-phase four-leg inverter according to the derivative of the predicted sliding mode surface includes: According to the predicted sliding surface, solving the derivative of the predicted sliding surface using a discretized equation and a linear difference; The derivative of the predicted sliding mode surface is set to 0, and the target output voltage function of the three-phase four-leg inverter is obtained by solving the problem.

4. The control method of the three-phase four-leg inverter according to claim 1, wherein: Based on the topology of the three-phase four-leg inverter, the three-phase reference voltage of the three-phase four-leg inverter in the three-phase stationary coordinate system is determined, including: Determining a current-voltage relationship between an output voltage and an output current of a three-phase four-leg inverter based on a topological structure of the three-phase four-leg inverter; According to the current-voltage relationship, Kirchhoff's law and Clarke transformation are used to obtain the three-phase reference voltage of the three-phase four-leg inverter in a three-phase stationary coordinate system.

5. The control method of the three-phase four-leg inverter according to claim 1, wherein: The method further comprises: An N-phase voltage of the three-phase four-leg inverter is calculated according to a target output voltage of the three-phase four-leg inverter.

6. A control device for a three-phase four-leg inverter, characterized in that: The device comprises: A voltage determination module is used to determine a three-phase reference voltage of the three-phase four-bridge-leg inverter in a three-phase stationary coordinate system based on the topology of the three-phase four-bridge-leg inverter; A function calculation module, configured to calculate an output voltage function of the three-phase four-leg inverter based on the three-phase reference voltage; the output voltage function includes a saturation function gain and a sliding mode surface adaptive weight coefficient; a coefficient solving module, configured to set an initial function gain and an initial adaptive weight coefficient; smooth the initial function gain using a sigmoid function to obtain the saturated function gain; determine a load voltage error of the three-phase four-leg inverter; and calculate the sliding surface adaptive weight coefficient using a sigmoid function based on the initial adaptive weight coefficient and the load voltage error; A voltage control module is used to substitute the saturation function gain and the sliding mode surface adaptive weight coefficient into the output voltage function to obtain the target output voltage of the three-phase four-leg inverter.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the control method of the three-phase four-leg inverter according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the control method of the three-phase four-leg inverter according to any one of claims 1 to 5 is implemented.

9. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of the three-phase four-leg inverter according to any one of claims 1 to 5 is implemented.

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