Off-grid inverter control method, device, equipment and medium

Abstract

The invention discloses an off-grid inverter control method and device, equipment and a medium, and belongs to the technical field of power electronics, and the method comprises the steps: carrying out the Park conversion of a given voltage of an off-grid inverter, and obtaining a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter comprises a single-phase inverter, a split-phase inverter and a three-phase inverter; processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using target control to obtain a target modulation wave; the target control comprises PI control and R control, or PI control and current feedforward control; and controlling the off-grid inverter by using the target modulation wave. According to the method, different types of off-grid inverters can be uniformly controlled.

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 medium for an off-grid inverter. Background Art

[0002] Off-grid inverters can be divided into single-phase inverters, split-phase inverters and three-phase inverters according to the type of output voltage. Different types of off-grid inverters use different control methods. For example, three-phase inverters use PI (Proportional Integral) control, while split-phase inverters use PR (Proportional Resonant) control. The inconsistency of control methods for various types of off-grid inverters will result in the need to design multiple control algorithms in the inverter control software to control the off-grid inverter, which greatly increases the difficulty of controlling the off-grid inverter. At present, there is no more effective solution to this technical problem.

[0003] It can be seen that how to uniformly control different types of off-grid inverters is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a control method, device, equipment and medium for an off-grid inverter to solve the technical problem that different types of off-grid inverters cannot be uniformly controlled in the prior art. The specific scheme is as follows:

[0005] In order to solve the above technical problems, the present invention provides a control method for an off-grid inverter, comprising:

[0006] Performing Park transformation on a given voltage of an off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter;

[0007] The voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control;

[0008] The off-grid inverter is controlled using the target modulation wave.

[0009] Preferably, performing Park transformation on a given voltage of the off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system includes:

[0010] If the off-grid inverter is the single-phase inverter, the single-phase given voltage of the single-phase inverter is determined to be the given voltage of phase a, and the given voltages of the single-phase inverter at phase b and phase c are determined to be 0, so as to perform Park transformation on the given voltages of the single-phase inverter at phase a, phase b and phase c, and obtain the voltage components of the single-phase inverter in the synchronous rotating coordinate system;

[0011] If the off-grid inverter is the split-phase inverter, the two-phase given voltages of the split-phase inverter are respectively determined as the given voltages of phase a and phase b, and the given voltage of the split-phase inverter at phase c is determined to be 0, so as to perform Park transformation on the given voltages of the split-phase inverter at phase a, phase b and phase c to obtain the voltage components of the split-phase inverter in a synchronous rotating coordinate system;

[0012] If the off-grid inverter is the three-phase inverter, Park transformation is performed on the given voltages of the three-phase inverter at phases a, b and c to obtain voltage components of the three-phase inverter in a synchronous rotating coordinate system.

[0013] Preferably, the process of processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by target control to obtain the target modulation wave includes:

[0014] Processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the target control to obtain a preprocessing signal;

[0015] Performing Park transformation on the given current of the off-grid inverter to obtain the current component of the off-grid inverter in a synchronous rotating coordinate system;

[0016] The PI control and the R control are used to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessing signal to obtain the target modulation wave.

[0017] Preferably, the using the target control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a preprocessing signal includes:

[0018] Processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the PI control to obtain a first processed signal;

[0019] Extracting an AC component of a current sampling value of the off-grid inverter in a synchronous rotating coordinate system to obtain a second processed signal;

[0020] Correspondingly, the PI control and the R control are used to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system, and the preprocessed signal to obtain the target modulation wave, including:

[0021] The first processed signal, the second processed signal, the current component of the off-grid inverter in the synchronous rotating coordinate system, and the current sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed in the current loop by using the PI control and the R control to obtain the target modulation wave.

[0022] Preferably, extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain the second processed signal includes:

[0023] Extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system by using a second-order bandpass filter to obtain the second processed signal;

[0024] Wherein, the transfer function of the second-order bandpass filter is:

[0025] ;

[0026] In the formula, is the passband gain, is the damping coefficient, is the center frequency.

[0027] Preferably, when the second processed signal is the d-axis component and the q-axis component of the off-grid inverter in the synchronous rotating coordinate system, the The value of When the second processed signal is the 0-axis component of the off-grid inverter in the synchronous rotating coordinate system, the The value of ; is the grid frequency.

[0028] Preferably, the The value of is 1.

[0029] In order to solve the above technical problems, the present invention further provides a control device for an off-grid inverter, comprising:

[0030] A coordinate transformation module, used for performing Park transformation on a given voltage of an off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter;

[0031] A signal processing module, used for processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by target control to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control;

[0032] An inverter control module is used to control the off-grid inverter using the target modulation wave.

[0033] In order to solve the above technical problem, the present invention further provides an electronic device, comprising:

[0034] Memory for storing computer programs;

[0035] The processor is used to implement the steps of the control method of an off-grid inverter disclosed above when executing the computer program.

[0036] In order to solve the above technical problem, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of a control method for an off-grid inverter disclosed above are implemented.

[0037] Beneficial effect: In the control method of the off-grid inverter provided by the present invention, first, the given voltages of different types of off-grid inverters are uniformly converted to a synchronous rotating coordinate system, and then, the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a target modulation wave, and the target modulation wave is used to control the off-grid inverter. Since the PI control in the target control can perform zero-static error control on the DC component of the off-grid inverter in the synchronous rotating coordinate system, and the R control or current feedforward control in the target control can perform zero-static error control on the AC component of the off-grid inverter in the synchronous rotating coordinate system, the method provided by the present invention can achieve zero-static error tracking of the given voltages of different types of off-grid inverters, thereby achieving the purpose of uniformly controlling different types of off-grid inverters.

[0038] Correspondingly, the control device, equipment and medium of an off-grid inverter provided by the present invention also have the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0040] Figure 1 A flow chart of a control method for an off-grid inverter provided by an embodiment of the present invention;

[0041] Figure 2 It is a structural diagram for processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using PI control and R control;

[0042] Figure 3 A schematic diagram of controlling an off-grid inverter using a voltage loop and a current loop double closed-loop control architecture provided by an embodiment of the present invention;

[0043] Figure 4 It is a schematic diagram of the result when the given current of the single-phase inverter is tracked on the d-axis of the synchronous rotating coordinate system;

[0044] Figure 5 It is a schematic diagram of the result when the given current of the single-phase inverter is tracked on the q-axis of the synchronous rotating coordinate system;

[0045] Figure 6 A schematic diagram of another embodiment of the present invention providing a control structure of a voltage loop and a current loop to control an off-grid inverter;

[0046] Figure 7 To adopt Figure 3 and Figure 6 A schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the d-axis of a synchronous rotating coordinate system when the control architecture shown is used to control the single-phase inverter;

[0047] Figure 8 To adopt Figure 3 and Figure 6 A schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the q-axis of a synchronous rotating coordinate system when the control architecture shown is used to control the single-phase inverter;

[0048] Fig. 9 To adopt Figure 3 and Figure 6 The control architecture shown is a schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the 0 axis of the synchronous rotating coordinate system when the single-phase inverter is controlled;

[0049] Fig.10 To adopt Figure 6 When the control architecture shown is used to control the single-phase inverter, a schematic diagram of a given current and a current sampling value of the single-phase inverter on the d-axis of the synchronous rotating coordinate system;

[0050] Fig.11 To adopt Figure 6 When the control architecture shown is used to control the single-phase inverter, a schematic diagram of a given current and a current sampling value of the single-phase inverter on the q-axis of a synchronous rotating coordinate system;

[0051] Fig.12 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the single-phase inverter on the 0 axis of the synchronous rotating coordinate system when the single-phase inverter is controlled;

[0052] Fig.13 To adopt Figure 6 A schematic diagram of a given current and a current sampling value of the split-phase inverter on the d-axis of a synchronous rotating coordinate system when the control architecture shown is used to control the split-phase inverter;

[0053] Fig.14 To adopt Figure 6 A schematic diagram of a given current and a current sampling value of the split-phase inverter on the q-axis of a synchronous rotating coordinate system when the control architecture shown is used to control the split-phase inverter;

[0054] Fig.15 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the split-phase inverter on the 0 axis of the synchronous rotating coordinate system when the split-phase inverter is controlled;

[0055] Fig.16 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the d-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition;

[0056] Fig.17 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the q-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition;

[0057] Fig.18 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the 0 axis of the synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition;

[0058] Fig.19To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the d-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a load asymmetry condition;

[0059] Fig. 20 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the q-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a load asymmetry condition;

[0060] Fig.21 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the 0 axis of the synchronous rotating coordinate system when the three-phase inverter is controlled under asymmetric load conditions;

[0061] Fig. 22 A structural diagram of a control device for an off-grid inverter provided by an embodiment of the present invention;

[0062] Fig.23 A structural diagram of a control device for an off-grid inverter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] See also Figure 1 , Figure 1 A flow chart of a control method for an off-grid inverter provided by an embodiment of the present invention, the method comprising:

[0065] Step S11: performing Park transformation on a given voltage of the off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter;

[0066] Step S12: using target control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control;

[0067] Step S13: using the target modulation wave to control the off-grid inverter.

[0068] In this embodiment, a control method for an off-grid inverter is provided, and the method can be used to uniformly control different types of off-grid inverters. In the method, first, a Park transformation is performed on a given voltage of the off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system. The off-grid inverter described in the present application can be a single-phase inverter, a split-phase inverter, or a three-phase inverter.

[0069] After Park transformation is performed on the given voltages of different types of off-grid inverters, the given voltages of different types of off-grid inverters can be uniformly converted to the synchronous rotating coordinate system. After that, the voltage components of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling values ​​of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain the target modulation wave. Among them, the target control can be either PI control and R control, or PI control and current feedforward control.

[0070] See also Figure 2 , Figure 2 This is a structural diagram for processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system using target control. Figure 2 middle, is the voltage given value of the off-grid inverter on the d-axis, q-axis and 0-axis, are the voltage sampling values ​​of the off-grid inverter on the d-axis, q-axis and 0-axis.

[0071] It should be noted that, in practical applications, when performing zero-error tracking on the given voltage of the off-grid inverter, it is necessary to perform zero-error tracking on the given voltage of the off-grid inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system respectively. Since the zero-error tracking principle and method on these three axes are the same, only the input parameters are different, therefore, in this embodiment, for the convenience of description and the convenience of understanding by the reader, the control methods on these three axes are combined and uniformly adopted. Figure 2 The accompanying drawings shown are described herein.

[0072] When the off-grid inverter is a three-phase inverter, since there is no missing phase in the three-phase voltage of the three-phase inverter, after the given voltage of the three-phase inverter is Park transformed, the voltage component of the three-phase inverter in the synchronous rotating coordinate system will be a DC component. Similarly, the voltage sampling value of the three-phase inverter in the synchronous rotating coordinate system will also be a DC component. At this time, PI control is directly used to process the voltage component of the three-phase inverter in the synchronous rotating coordinate system and the voltage sampling value of the three-phase inverter in the synchronous rotating coordinate system. After obtaining the target modulation wave, the target modulation wave is used to control the three-phase inverter, so as to achieve the purpose of zero-static error tracking of the given voltage of the three-phase inverter.

[0073] When the off-grid inverter is a split-phase inverter or a single-phase inverter, the split-phase inverter and the single-phase inverter lack one-phase voltage or two-phase voltage compared to the three-phase inverter. Then, after the given voltage of the single-phase inverter (split-phase inverter) is Park transformed, the voltage component of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system will be a mixture of DC component and AC component. Similarly, the voltage sampling value of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system will also be a mixture of DC component and AC component. In this case, in order to achieve zero-static tracking of the given voltage of the single-phase inverter (split-phase inverter), it is necessary to use PI control to control the DC component of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system, and use R control or current feedforward control to control the AC component of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system. That is, by using PI control and R control (or PI control and current feedforward control) to process the voltage components of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system and the voltage sampling values ​​of the single-phase inverter (split-phase inverter) in the synchronous rotating coordinate system, and obtaining the target modulation wave, the single-phase inverter (split-phase inverter) is controlled by the target modulation wave, thereby achieving the purpose of zero-static error tracking of the given voltage of the single-phase inverter (split-phase inverter).

[0074] Among them, the transfer function expression of R control is:

[0075] ;

[0076] In the formula, is the gain coefficient of the R controller, is the resonant bandwidth, is the resonant frequency.

[0077] In the control method of the off-grid inverter provided in the present embodiment, first, the given voltages of different types of off-grid inverters are uniformly converted to a synchronous rotating coordinate system, and then, the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a target modulation wave, and the target modulation wave is used to control the off-grid inverter. Since the PI control in the target control can perform zero-static error control on the DC component of the off-grid inverter in the synchronous rotating coordinate system, and the R control or current feedforward control in the target control can perform zero-static error control on the AC component of the off-grid inverter in the synchronous rotating coordinate system, the method provided in the present embodiment can realize zero-static error tracking of the given voltages of different types of off-grid inverters, thereby achieving the purpose of uniformly controlling different types of off-grid inverters.

[0078] Based on the above embodiment, this embodiment further illustrates and optimizes the technical solution. As a preferred implementation, the above step S11: performing Park transformation on the given voltage of the off-grid inverter to obtain the voltage component of the off-grid inverter in the synchronous rotating coordinate system includes:

[0079] If the off-grid inverter is a single-phase inverter, the single-phase given voltage of the single-phase inverter is determined as the given voltage of phase a, and the given voltages of the single-phase inverter at phase b and phase c are determined to be 0, so as to perform Park transformation on the given voltages of the single-phase inverter at phase a, phase b and phase c, and obtain the voltage components of the single-phase inverter in the synchronous rotating coordinate system;

[0080] If the off-grid inverter is a split-phase inverter, the two-phase given voltages of the split-phase inverter are respectively determined as the given voltages of phase a and phase b, and the given voltage of the split-phase inverter at phase c is determined to be 0, so as to perform Park transformation on the given voltages of the split-phase inverter at phase a, phase b and phase c, and obtain the voltage components of the split-phase inverter in the synchronous rotating coordinate system;

[0081] If the off-grid inverter is a three-phase inverter, Park transformation is performed on the given voltages of the three-phase inverter at phases a, b and c to obtain the voltage components of the three-phase inverter in a synchronous rotating coordinate system.

[0082] In this embodiment, the Park transformation of different types of off-grid inverters is specifically described. When the off-grid inverter is a three-phase inverter, because the given voltage of the three-phase inverter does not have a phase loss, the given voltage of the off-grid inverter in phase a, phase b and phase c can be directly Park transformed to obtain the voltage component of the off-grid inverter in the synchronous rotating coordinate system.

[0083] Among them, the mathematical expression of Park transformation is:

[0084] ;

[0085] In the formula, , is the angular frequency, is the frequency.

[0086] When the off-grid inverter is a single-phase inverter, since the given voltage of the single-phase inverter has only one phase, a phase loss situation occurs. At this time, in order to perform Park transformation on the given voltage of the single-phase inverter, the single-phase given voltage of the single-phase inverter can be determined as the given voltage of phase a, and the given voltages of the single-phase inverter in phases b and c can be determined as 0, and the given voltages of the single-phase inverter in phases a, b and c can be Park transformed to obtain the voltage components of the single-phase inverter in the synchronous rotating coordinate system.

[0087] Specifically, the voltage component of the single-phase inverter in the synchronous rotating coordinate system is:

[0088] ;

[0089] After sorting, we can get formula 1:

[0090] ;

[0091] in, , and are the voltage components of the single-phase inverter on the d-axis, q-axis and 0-axis respectively, It is the single-phase given voltage of the single-phase inverter.

[0092] Of course, in practical applications, the single-phase given voltage of the single-phase inverter can also be determined as the b-phase voltage, and the given voltages of the a-phase and c-phases of the single-phase inverter can be determined as 0 to perform Park transformation on the given voltages of the a-phase, b-phase and c-phases of the single-phase inverter. Alternatively, the single-phase given voltage of the single-phase inverter can also be determined as the c-phase voltage, and the given voltages of the a-phase and b-phases of the single-phase inverter can be determined as 0 to perform Park transformation on the given voltages of the a-phase, b-phase and c-phases of the single-phase inverter.

[0093] When the off-grid inverter is a split-phase inverter, since the given voltage of the split-phase inverter has only two phases, a phase loss occurs. At this time, in order to perform Park transformation on the given voltage of the split-phase inverter, the two-phase given voltages of the split-phase inverter can be judged as the given voltages of phase a and phase b respectively, and the given voltage of the split-phase inverter in phase c can be judged as 0, and the given voltages of the split-phase inverter in phase a, phase b and phase c can be Park transformed to obtain the voltage components of the split-phase inverter in the synchronous rotating coordinate system. The specific transformation process can be referred to the Park transformation of the single-phase inverter, which will not be repeated here.

[0094] Of course, in practical applications, the two-phase given voltages of the split-phase inverter can be determined as the a-phase voltage and the c-phase voltage, and the given voltage of the b-phase of the split-phase inverter can be determined as 0 to perform Park transformation on the given voltages of the split-phase inverter at the a-phase, b-phase and c-phase. Alternatively, the two-phase given voltages of the split-phase inverter can be determined as the b-phase voltage and the c-phase voltage, and the given voltage of the a-phase of the split-phase inverter can be determined as 0 to perform Park transformation on the given voltages of the split-phase inverter at the a-phase, b-phase and c-phase.

[0095] Obviously, through the technical solution provided in this embodiment, regardless of whether the off-grid inverter is a three-phase inverter, a single-phase inverter or a split-phase inverter, Park transformation can be performed on it.

[0096] Based on the above embodiment, this embodiment further illustrates and optimizes the technical solution. As a preferred implementation, the above step S12: using target control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain the target modulation wave includes:

[0097] The voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a preprocessing signal;

[0098] Perform Park transformation on the given current of the off-grid inverter to obtain the current component of the off-grid inverter in the synchronous rotating coordinate system;

[0099] The PI control and R control are used to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessing signal to obtain the target modulation wave.

[0100] In general scenarios, as long as the given voltage of the off-grid inverter can be accurately and stably tracked, the purpose of controlling the off-grid inverter can be achieved. However, in practical applications, a dual closed-loop system of voltage loop and current loop is usually used to control the off-grid inverter. In this case, a current loop can be added at the back end of the voltage loop to control the off-grid inverter. See Figure 3 , Figure 3 A schematic diagram of controlling an off-grid inverter using a dual closed-loop control architecture of a voltage loop and a current loop provided by an embodiment of the present invention.

[0101] exist Figure 3 middle, is the voltage given value of the off-grid inverter on the d-axis, q-axis and 0-axis, are the voltage sampling values ​​of the off-grid inverter on the d-axis, q-axis and 0-axis. is the current given value of the off-grid inverter on the d-axis, q-axis and 0-axis, are the current sampling values ​​of the off-grid inverter on the d-axis, q-axis and 0-axis.

[0102] When obtaining the target modulation wave for controlling the off-grid inverter, it is necessary to perform Park transformation on the given current of the off-grid inverter to obtain the current component of the off-grid inverter in the synchronous rotating coordinate system; at the same time, the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a preprocessed signal; thereafter, the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessed signal are processed by PI control and R control to obtain the target modulation wave.

[0103] use Figure 3 The control architecture shown can accurately track the given voltage of the off-grid inverter in the synchronous rotating coordinate system without static error, but it cannot accurately track the given current of the off-grid inverter in the synchronous rotating coordinate system without static error. Figure 4 and Figure 5 , Figure 4 It is a schematic diagram of the results of tracking a given current of a single-phase inverter on the d-axis of a synchronous rotating coordinate system. Figure 5 The following is a schematic diagram of the results of tracking a given current of a single-phase inverter on the q-axis of a synchronous rotating coordinate system. Figure 4 middle, is the given current of the single-phase inverter on the d-axis, is the current sampling value of the single-phase inverter on the d axis. Figure 5 middle, is the given current of the single-phase inverter on the q axis, is the current sampling value of the single-phase inverter on the q axis. Figure 4 and Figure 5 As can be seen in and Unable to accurately track and , this is because the output controlled by R is not a given value of the AC component of the current.

[0104] In order to solve this technical problem, we can also Figure 3 As a preferred implementation, the above step: using target control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a preprocessing signal includes:

[0105] Using PI control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a first processed signal;

[0106] Extracting an AC component of a current sampling value of the off-grid inverter in a synchronous rotating coordinate system to obtain a second processed signal;

[0107] Accordingly, the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessing signal are processed by PI control and R control to obtain the target modulation wave, including:

[0108] In the current loop, the first processing signal, the second processing signal, the current component of the off-grid inverter in the synchronous rotating coordinate system, and the current sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by PI control and R control to obtain a target modulation wave.

[0109] In this embodiment, in order to solve the technical problem of not being able to accurately track the given current of the off-grid inverter, the AC component of the off-grid inverter in the rotating coordinate system can also be extracted, and the AC component of the off-grid inverter in the synchronous rotating coordinate system is added to the control loop of the voltage loop as a feedforward quantity.

[0110] See also Figure 6 , Figure 6 A schematic diagram of another embodiment of the present invention using a voltage loop and a current loop double closed loop control architecture to control an off-grid inverter. Figure 6 In the equation, BPF represents a second-order bandpass filter. is the voltage given value of the off-grid inverter on the d-axis, q-axis and 0-axis, are the voltage sampling values ​​of the off-grid inverter on the d-axis, q-axis and 0-axis. is the current given value of the off-grid inverter on the d-axis, q-axis and 0-axis, are the current sampling values ​​of the off-grid inverter on the d-axis, q-axis and 0-axis.

[0111] In order to enable the current loop to accurately track the given current of the off-grid inverter, the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system can be processed by PI control to obtain a first processing signal. At the same time, the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system is extracted to obtain a second processing signal; then, the first processing signal, the second processing signal, the current component of the off-grid inverter in the synchronous rotating coordinate system and the current sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed in the current loop by PI control and R control to obtain the target modulation wave.

[0112] As a preferred implementation, the above step of extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain the second processed signal includes:

[0113] Extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system by using a second-order bandpass filter to obtain a second processed signal;

[0114] Among them, the transfer function of the second-order bandpass filter is:

[0115] ;

[0116] In the formula, is the passband gain, is the damping coefficient, is the center angular frequency.

[0117] Specifically, in this embodiment, a second-order band pass filter (Band Pass Filter, BPF) can be used to extract the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system. Because the parameters such as the center angular frequency and bandwidth of the second-order band pass filter can be adjusted compared to other types of filters, the second-order band pass filter can be applied to different application scenarios.

[0118] In addition, the second-order bandpass filter can also attenuate out-of-band signals and reduce the influence of noise on its filtering effect, so that the AC component can be more accurately extracted from the current sampling value of the off-grid inverter in the synchronous rotating coordinate system.

[0119] As a preferred implementation, in the above step: when the second processed signal is the d-axis component and the q-axis component of the off-grid inverter in the synchronous rotating coordinate system, The value of ; When the second processed signal is the 0-axis component of the off-grid inverter in the synchronous rotating coordinate system, The value of ; is the grid frequency.

[0120] According to the expression of formula 1, if the off-grid inverter is a single-phase inverter or a split-phase inverter, there is a double-frequency AC component in the current sampling values ​​of the d-axis and q-axis of the synchronous rotating coordinate system of the single-phase inverter and the split-phase inverter. Therefore, according to this property characteristic of the AC component, the center angular frequency of the second-order bandpass filter can be adjusted, thereby ensuring the accuracy and reliability of the AC component extraction results.

[0121] Specifically, when the grid frequency is 50 Hz, the AC component of the off-grid inverter on the d-axis and q-axis of the synchronous rotating coordinate system is 100 Hz, and the AC component of the off-grid inverter on the 0-axis of the synchronous rotating coordinate system is 50 Hz. In this case, if the second processed signal is the d-axis component and the q-axis component of the off-grid inverter in the synchronous rotating coordinate system, the center angular frequency of the second-order bandpass filter can be Set to 200 Hz, if the second processed signal is the AC component of the off-grid inverter on the 0-axis of the synchronous rotating coordinate system, the center angular frequency of the second-order bandpass filter can be Set to 100 Hz.

[0122] Alternatively, when the grid frequency is 60 Hz, the AC component of the off-grid inverter on the d-axis and q-axis of the synchronous rotating coordinate system is 120 Hz, and the AC component of the off-grid inverter on the 0-axis of the synchronous rotating coordinate system is 60 Hz. In this case, if the second processed signal is the d-axis component and the q-axis component of the off-grid inverter in the synchronous rotating coordinate system, the center angular frequency of the second-order bandpass filter can be Set to 240 Hz, if the second processed signal is the AC component of the off-grid inverter on the 0-axis of the synchronous rotating coordinate system, the center angular frequency of the second-order bandpass filter can be Set to 120 Hz.

[0123] In addition, in this embodiment, since it is necessary to use all AC components of the current sampling values ​​of the off-grid inverter in the synchronous rotating coordinate system as feedforward quantities to control the current loop, the bandpass gain of the second-order bandpass filter can be is set to 1. Also, the damping coefficient in the second-order bandpass filter The smaller the value, the smaller the filter bandwidth and the lower the harmonic content after filtering. However, too small a bandwidth will affect the dynamic performance of the second-order bandpass filter. After comprehensively considering the current harmonics after filtering, system stability and the dynamic performance of the system, the damping coefficient of the second-order bandpass filter can be Set to 0.1.

[0124] See also Figures 7 to 9 , Figure 7 To adopt Figure 3 and Figure 6 The control architecture shown is a schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the d-axis of the synchronous rotating coordinate system when the single-phase inverter is controlled. Figure 8 To adopt Figure 3 and Figure 6 The control architecture shown is a schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the q-axis of the synchronous rotating coordinate system when the single-phase inverter is controlled. Fig. 9 To adopt Figure 3 and Figure 6 The control architecture shown is a schematic diagram of a given voltage and a voltage sampling value of the single-phase inverter on the 0-axis of the synchronous rotating coordinate system when the single-phase inverter is controlled.

[0125] exist Figures 7 to 9 middle, , and are the voltage reference values ​​of the single-phase inverter under the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system, respectively. , and are the voltage sampling values ​​of the single-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system. Figures 7 to 9 It can be seen that whether using Figure 3 The control architecture shown in the figure is used to control the single-phase inverter, or Figure 6 The control architecture shown is used to control the single-phase inverter, and the voltage set values ​​of the single-phase inverter on the d-axis, q-axis and 0-axis can be accurately tracked without static error.

[0126] See also Figures 10 to 12 , Fig.10 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the single-phase inverter on the d-axis of the synchronous rotating coordinate system when the single-phase inverter is controlled. Fig.11 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the single-phase inverter on the q-axis of a synchronous rotating coordinate system when the single-phase inverter is controlled. Fig.12 To adopt Figure 6The control architecture shown is a schematic diagram of a given current and a current sampling value of the single-phase inverter on the 0-axis of the synchronous rotating coordinate system when the single-phase inverter is controlled.

[0127] exist Figures 10 to 12 middle, , and are the current given values ​​of the single-phase inverter under the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system, respectively. , and are the current sampling values ​​of the single-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system. Figures 10 to 12 It can be seen that the current given value and current sampling value of the single-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system are basically coincident, indicating that the use of Figure 6 When the control architecture shown is used to control the single-phase inverter, the given current of the single-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system can be accurately tracked without static error.

[0128] See also Figures 13 to 15 , Fig.13 To adopt Figure 6 The control architecture shown is a schematic diagram of the split-phase inverter giving current and current sampling values ​​on the d-axis of the synchronous rotating coordinate system when the split-phase inverter is controlled. Fig.14 To adopt Figure 6 The control architecture shown is a schematic diagram of the given current and current sampling value of the split-phase inverter on the q-axis of the synchronous rotating coordinate system when the split-phase inverter is controlled. Fig.15 To adopt Figure 6 The control architecture shown is a schematic diagram of the split-phase inverter giving current and current sampling values ​​on the 0-axis of the synchronous rotating coordinate system when the split-phase inverter is controlled.

[0129] exist Figures 13 to 15 middle, , and are the current given values ​​of the split-phase inverter under the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system, respectively. , and are the current sampling values ​​of the split-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system. Figures 13 to 15 It can be seen that the current given value and current sampling value of the split-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system are basically coincident, indicating that the use of Figure 6 When the split-phase inverter is controlled by the control architecture shown, the given current of the split-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system can be accurately tracked without static error.

[0130] See also Figures 16 to 18 , Fig.16 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the d-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition. Fig.17 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the q-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition. Fig.18 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the 0-axis of the synchronous rotating coordinate system when the three-phase inverter is controlled under a symmetrical load condition.

[0131] exist Figures 16 to 18 middle, , and are the current given values ​​of the three-phase inverter under the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system, respectively. , and are the current sampling values ​​of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system. Figures 16 to 18 It can be seen that when the load is symmetrical, the current given value and current sampling value of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system basically coincide, indicating that the use of Figure 6 When the control architecture shown is used to control a three-phase inverter in a load symmetry situation, the given current of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system can be accurately tracked without static error.

[0132] See also Figures 19 to 21 , Fig.19 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the d-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under an asymmetric load condition. Fig. 20 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the q-axis of a synchronous rotating coordinate system when the three-phase inverter is controlled under an asymmetric load condition. Fig.21 To adopt Figure 6 The control architecture shown is a schematic diagram of a given current and a current sampling value of the three-phase inverter on the 0-axis of the synchronous rotating coordinate system when the three-phase inverter is controlled under an asymmetric load condition.

[0133] exist Figures 19 to 21 middle, , and are the current given values ​​of the three-phase inverter under the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system, respectively. , and are the current sampling values ​​of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system. Figures 19 to 21 It can be seen that when the load is asymmetric, the current given value and current sampling value of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system basically coincide, indicating that the use of Figure 6 When the control architecture shown is used to control a three-phase inverter under a load asymmetry situation, the given current of the three-phase inverter on the d-axis, q-axis and 0-axis of the synchronous rotating coordinate system can be accurately tracked without static error.

[0134] In summary, no matter what type of off-grid inverter is used, Figure 6 The control architectures shown can all accurately track the given voltage and given current of the off-grid inverter in a synchronous rotating coordinate system without static error.

[0135] See also Fig. 22 , Fig. 22 A structural diagram of a control device for an off-grid inverter provided by an embodiment of the present invention, the device comprising:

[0136] A coordinate transformation module 21, used for performing Park transformation on a given voltage of an off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter;

[0137] The signal processing module 22 is used to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using target control to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control;

[0138] The inverter control module 23 is used to control the off-grid inverter using the target modulation wave.

[0139] Preferably, the coordinate transformation module 21 includes:

[0140] A first conversion submodule is used for, if the off-grid inverter is the single-phase inverter, determining the single-phase given voltage of the single-phase inverter as the given voltage of phase a, and determining the given voltages of the single-phase inverter at phase b and phase c as 0, so as to perform Park transformation on the given voltages of the single-phase inverter at phase a, phase b and phase c, and obtain voltage components of the single-phase inverter in a synchronous rotating coordinate system;

[0141] A second conversion submodule is used for, if the off-grid inverter is the split-phase inverter, determining the two-phase given voltages of the split-phase inverter as the given voltages of phase a and phase b respectively, and determining the given voltage of the split-phase inverter at phase c as 0, so as to perform Park transformation on the given voltages of the split-phase inverter at phase a, phase b and phase c, and obtain the voltage components of the split-phase inverter in a synchronous rotating coordinate system;

[0142] The third conversion submodule is used to perform Park transformation on the given voltages of the three-phase inverter at phases a, b and c if the off-grid inverter is the three-phase inverter, so as to obtain the voltage components of the three-phase inverter in a synchronous rotating coordinate system.

[0143] Preferably, the signal processing module 22 includes:

[0144] A signal preprocessing submodule, used for processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the target control to obtain a preprocessing signal;

[0145] A current conversion submodule, used for performing Park transformation on a given current of the off-grid inverter to obtain a current component of the off-grid inverter in a synchronous rotating coordinate system;

[0146] The signal processing submodule uses the PI control and the R control to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessing signal to obtain the target modulation wave.

[0147] Preferably, the signal preprocessing submodule includes:

[0148] a first processing unit, configured to process a voltage component of the off-grid inverter in a synchronous rotating coordinate system and a voltage sampling value of the off-grid inverter in a synchronous rotating coordinate system by using the PI control to obtain a first processing signal;

[0149] A second processing unit, configured to extract an AC component of a current sampling value of the off-grid inverter in a synchronous rotating coordinate system to obtain a second processing signal;

[0150] Accordingly, the signal processing submodule includes:

[0151] A signal processing unit is used to process the first processed signal, the second processed signal, the current component of the off-grid inverter in the synchronous rotating coordinate system, and the current sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the PI control and the R control in the current loop to obtain the target modulation wave.

[0152] Preferably, the second processing unit comprises:

[0153] a signal processing subunit, configured to extract an AC component of a current sampling value of the off-grid inverter in a synchronous rotating coordinate system by using a second-order bandpass filter to obtain the second processed signal;

[0154] Wherein, the transfer function of the second-order bandpass filter is:

[0155] ;

[0156] In the formula, is the passband gain, is the damping coefficient, is the center frequency.

[0157] A control device for an off-grid inverter provided in an embodiment of the present invention has the beneficial effects of the control method for an off-grid inverter disclosed above.

[0158] See also Fig.23 , Fig.23 A structural diagram of an electronic device provided by an embodiment of the present invention, the device includes:

[0159] A memory 31, used for storing computer programs;

[0160] The processor 32 is used to implement the steps of the off-grid inverter control method disclosed above when executing the computer program.

[0161] An electronic device provided by an embodiment of the present invention has the beneficial effects of the aforementioned off-grid inverter control method.

[0162] Correspondingly, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the control method of an off-grid inverter disclosed above are implemented.

[0163] A computer-readable storage medium provided in an embodiment of the present invention has the beneficial effects of the aforementioned off-grid inverter control method disclosed above.

[0164] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0165] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0166] The control method, device, equipment and medium of an off-grid inverter provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in the field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A control method for an off-grid inverter, characterized in that: include: Performing Park transformation on a given voltage of an off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter; The voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed by target control to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control; The off-grid inverter is controlled using the target modulation wave.

2. The control method of an off-grid inverter according to claim 1, characterized in that: The performing Park transformation on the given voltage of the off-grid inverter to obtain the voltage component of the off-grid inverter in the synchronous rotating coordinate system includes: If the off-grid inverter is the single-phase inverter, the single-phase given voltage of the single-phase inverter is determined to be the given voltage of phase a, and the given voltages of the single-phase inverter at phase b and phase c are determined to be 0, so as to perform Park transformation on the given voltages of the single-phase inverter at phase a, phase b and phase c, and obtain the voltage components of the single-phase inverter in the synchronous rotating coordinate system; If the off-grid inverter is the split-phase inverter, the two-phase given voltages of the split-phase inverter are respectively determined as the given voltages of phase a and phase b, and the given voltage of the split-phase inverter at phase c is determined to be 0, so as to perform Park transformation on the given voltages of the split-phase inverter at phase a, phase b and phase c to obtain the voltage components of the split-phase inverter in a synchronous rotating coordinate system; If the off-grid inverter is the three-phase inverter, Park transformation is performed on the given voltages of the three-phase inverter at phases a, b and c to obtain voltage components of the three-phase inverter in a synchronous rotating coordinate system.

3. The control method of an off-grid inverter according to claim 1, characterized in that: The target control is used to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a target modulation wave, including: Processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the target control to obtain a preprocessing signal; Performing Park transformation on the given current of the off-grid inverter to obtain the current component of the off-grid inverter in a synchronous rotating coordinate system; The PI control and the R control are used to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system and the preprocessing signal to obtain the target modulation wave.

4. The control method of an off-grid inverter according to claim 3, characterized in that: The using the target control to process the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a preprocessing signal includes: Processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by using the PI control to obtain a first processed signal; Extracting an AC component of a current sampling value of the off-grid inverter in a synchronous rotating coordinate system to obtain a second processed signal; Correspondingly, the PI control and the R control are used to process the current component of the off-grid inverter in the synchronous rotating coordinate system, the current sampling value of the off-grid inverter in the synchronous rotating coordinate system, and the preprocessed signal to obtain the target modulation wave, including: The first processed signal, the second processed signal, the current component of the off-grid inverter in the synchronous rotating coordinate system, and the current sampling value of the off-grid inverter in the synchronous rotating coordinate system are processed in the current loop by using the PI control and the R control to obtain the target modulation wave.

5. The control method of an off-grid inverter according to claim 4, characterized in that: The step of extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system to obtain a second processed signal includes: Extracting the AC component of the current sampling value of the off-grid inverter in the synchronous rotating coordinate system by using a second-order bandpass filter to obtain the second processed signal; Wherein, the transfer function of the second-order bandpass filter is: ； In the formula, is the passband gain, is the damping coefficient, is the center angular frequency.

6. The control method of an off-grid inverter according to claim 5, characterized in that: When the second processed signal is the d-axis component and the q-axis component of the off-grid inverter in the synchronous rotating coordinate system, the The value of ; When the second processed signal is the 0-axis component of the off-grid inverter in the synchronous rotating coordinate system, the The value of ; is the grid frequency.

7. The control method of an off-grid inverter according to claim 5, characterized in that: Said The value of is 1.

8. A control device for an off-grid inverter, characterized in that: include: A coordinate transformation module, used for performing Park transformation on a given voltage of an off-grid inverter to obtain a voltage component of the off-grid inverter in a synchronous rotating coordinate system; wherein the off-grid inverter includes a single-phase inverter, a split-phase inverter and a three-phase inverter; A signal processing module, used for processing the voltage component of the off-grid inverter in the synchronous rotating coordinate system and the voltage sampling value of the off-grid inverter in the synchronous rotating coordinate system by target control to obtain a target modulation wave; the target control includes: PI control and R control, or PI control and current feedforward control; An inverter control module is used to control the off-grid inverter using the target modulation wave.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of a control method for an off-grid inverter as claimed in any one of claims 1 to 7 when executing the computer program.

10. 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 steps of the off-grid inverter control method according to any one of claims 1 to 7 are implemented.

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