Inverter control method, system and device under nonlinear load and storage medium
By designing a notch filter in the inverter to filter the harmonic components of the current signal, the problems of steady-state error and harmonic distortion of the inverter output voltage under nonlinear loads are solved, achieving efficient voltage waveform improvement and system stability.
Patent Information
- Application Number
- CN202511157539.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-19
- Publication Date
- 2025-11-18
AI Technical Summary
In off-grid operation environments, nonlinear loads cause steady-state errors and harmonic distortion in the inverter output voltage. Traditional PI controllers cannot effectively suppress high-frequency components, affecting power quality and the operation of load equipment.
By acquiring the voltage and current signals at the inverter output, converting them into components in a rotating coordinate system, and designing a notch filter based on the harmonic order measured by the nonlinear load for filtering, only the target harmonic components of the current signal are filtered to generate a control signal to adjust the inverter output voltage.
It effectively suppresses harmonic interference introduced by nonlinear loads, improves the waveform quality of inverter output voltage, reduces control deviation, ensures system control stability, and does not require additional hardware costs.
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Figure CN120979142A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power control technology, and in particular to an inverter control method, system, device and storage medium under nonlinear load. Background Technology
[0002] Off-grid energy storage inverters, as core devices ensuring stable power supply at the end of the grid, have made their control methods an important research direction in the field of energy storage and inverter technology. In typical applications of single-phase inverters, a dual closed-loop control strategy based on a rotating coordinate system is usually adopted, such as... Figure 1 As shown, in this control architecture, the voltage and current signals at the inverter output are sampled and first generated into α and β components by an orthogonal signal generator, forming a two-phase AC signal in a stationary coordinate system. Then, through coordinate transformation, the α and β components are mapped to a rotating coordinate system to obtain the corresponding D and Q components, realizing the transformation of the signal from AC to DC. Finally, the D and Q components are used as control inputs to the inverter's current / voltage dual-loop PI control loop to achieve stable control of the inverter's output voltage. This control method decouples the AC signal and converts it to DC through coordinate transformation, thereby simplifying the controller design and improving the system's steady-state performance and dynamic response speed. It has been verified to have good control performance when driving a linear load.
[0003] However, in off-grid operation, when multiple nonlinear loads are connected, a large number of high-order harmonics are superimposed on the current signals of the nonlinear loads, causing the D and Q components after αβ / dq transformation to contain high-frequency AC ripple. Traditional PI controllers, due to their limited bandwidth, cannot completely suppress these high-frequency components, leading to output voltage steady-state errors and harmonic distortion (increased THD), reducing power quality, affecting the operation of load equipment, and increasing losses. Summary of the Invention
[0004] One objective of this application is to improve control accuracy by suppressing high-order harmonic interference in the current signal, thereby improving the waveform quality of the inverter output voltage and effectively alleviating the control deviation and output distortion problems caused by feedback signal distortion.
[0005] According to a first aspect of this application, an inverter control method under a nonlinear load is provided, the method comprising: Acquire the voltage and current signals at the output of the inverter, and convert the voltage and current signals into components in a rotating coordinate system; Based on at least one target harmonic number obtained from the measurement of the nonlinear load, the target harmonic number in the component of the rotating coordinate system obtained by the conversion of the current signal is filtered to obtain the filtered component in the rotating coordinate system. The components in the rotating coordinate system converted from the voltage signal and the components in the rotating coordinate system filtered from the current signal are input into an inverter controller to generate a control signal for adjusting the output voltage of the inverter.
[0006] In a specific implementation, the filtering of the components in the rotating coordinate system converted from the current signal includes: measuring the harmonic frequencies generated by the nonlinear load and determining at least one harmonic frequency as a target harmonic frequency; designing a notch filter for suppressing the corresponding harmonic component for each target harmonic frequency, and the target harmonic frequency corresponds to the notch filter one by one; discretizing the notch filter by using a bilinear transformation method, and applying all the discretized notch filters to the components in the rotating coordinate system converted from the current signal to filter the target harmonic frequencies.
[0007] In a specific implementation, the design of the notch filter for suppressing the corresponding harmonic component for each target harmonic frequency includes: the fundamental frequency of the output voltage of the inverter and the target harmonic frequency, the center frequency of the notch filter is calculated as follows: ; wherein, the center frequency of the notch filter is f0, the target harmonic frequency is n.
[0008] In a specific implementation, the discretization of the notch filter by using the bilinear transformation method includes: based on the set sampling period, the continuous time domain variables in the notch filter are converted into discrete time domain variables by using a bilinear transformation calculation formula; According to the variable conversion result, the continuous time transfer function of the notch filter is mapped into the corresponding discrete time transfer function; based on the discrete time transfer function, a difference equation in the discrete time domain is constructed; The coefficients of the difference equation are determined by the center frequency, the damping ratio and the sampling period of the notch filter, and are used to filter the target harmonic frequencies in the discrete time domain.
[0009] In a specific implementation, the filtering of the target harmonic frequencies by applying all the discretized notch filters to the components in the rotating coordinate system converted from the current signal includes: The components of the current signal converted in the rotating coordinate system are input into a plurality of notch filters for different target harmonic numbers and subjected to discretization processing, the notch filters filter out the interference signals of the corresponding harmonic components respectively, and components of the current signal filtered in the rotating coordinate system are obtained.
[0010] In a specific implementation, after obtaining the voltage signal and the current signal of the inverter output end, the method further includes: The voltage signal and the current signal of the inverter output end are obtained, and the voltage signal and the current signal are input into a second-order generalized integrator to generate orthogonal signal components corresponding to the voltage signal and the current signal.
[0011] In a specific implementation, after generating the orthogonal signal components corresponding to the voltage signal and the current signal, the method further includes: The orthogonal signal components corresponding to the voltage signal and the current signal are converted into components in a rotating coordinate system through a PARK transformation.
[0012] According to a second aspect of the present application, an inverter control system under a nonlinear load is provided, including: A signal conversion module is configured to obtain a voltage signal and a current signal of an inverter output end, and convert the voltage signal and the current signal into components in a rotating coordinate system; A signal filtering module is configured to filter target harmonic numbers in the components in the rotating coordinate system converted from the current signal based on at least one target harmonic number measured from the nonlinear load, to obtain filtered components in the rotating coordinate system; A signal integration module is configured to input the components in the rotating coordinate system converted from the voltage signal and the filtered components in the rotating coordinate system of the current signal into an inverter controller, to generate a control signal for adjusting an inverter output voltage.
[0013] According to a third aspect of the present application, an electronic device is provided, including a processor and a memory; the memory stores a program, the program is loaded and executed by the processor to implement the inverter control method under a nonlinear load according to the first aspect.
[0014] According to a fourth aspect of the present application, a computer readable storage medium is provided, the storage medium stores a program, and the program is executed by a processor to implement the inverter control method under a nonlinear load according to the first aspect.
[0015] According to the scheme of the application, the voltage signal and the current signal are converted into components in a rotating coordinate system, the components of the voltage signal are directly used in the voltage control loop without filtering in the control strategy, the components of the current signal are filtered at a target harmonic number, and finally the filtered current signal components and the unfiltered voltage signal components are input into the inverter controller. Compared with the conventional scheme which generally adopts a unified processing mode for the voltage and current signals, the application first proposes to structurally decouple and process the voltage signal and the current signal, only applies filtering operation to the target harmonic components in the current signal, and retains the original form of the voltage signal components. The strategy not only effectively weakens the interference of the current feedback harmonics caused by the nonlinear load on the controller performance, reduces the control deviation, and makes the inverter output voltage tend to be an ideal sinusoidal waveform, but also avoids changing the voltage control loop structure, thereby ensuring the control stability of the system. The control mode of limiting the filtering operation to the current channel rather than uniformly processing all feedback paths breaks the conventional thinking of symmetrical filtering or overall compensation of the technical personnel in the control structure design, and helps to improve the sinusoidal waveform quality of the inverter output voltage without increasing the complexity of the system.
[0016] Moreover, the inverter control method proposed in the application only based on the existing voltage signal and current signal, by adding a current signal filtering step based on the target harmonic number, the harmonic interference introduced by the nonlinear load is effectively suppressed. Compared with the conventional scheme which relies on external filter or additional sampling module, the filter used in the method is a notch structure realized in the control system, without introducing additional physical filter or hardware module, without introducing additional hardware cost.
[0017] The above description is only a summary of the technical scheme of the application. In order to more clearly understand the technical means of the application, and to implement the content of the description, the following will be described in detail with reference to the preferred embodiments of the application and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is the control block diagram of the conventional single-direction inverter in the embodiment of the application.
[0019] Figure 2 is the flowchart of the inverter control method under the nonlinear load in the embodiment of the application.
[0020] Figure 3 is the control block diagram of the inverter control method under the nonlinear load in the embodiment of the application.
[0021] Figure 4 is the structural block diagram of the inverter control system under the nonlinear load in the embodiment of the application.
[0022] Figure 5 is a block diagram of an electronic device for inverter control under nonlinear load in an embodiment of the present application. DETAILED DESCRIPTION
[0023] The specific embodiments of the present application are described in further detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not used to limit the scope of the present application.
[0024] First, the key terms related to the field of the present application are introduced as follows: Second-order generalized integrator: namely SOGI, which can decompose a single-phase sinusoidal input into in-phase component (vα, 0° offset) and quadrature component (vβ, 90° offset), forming two strictly orthogonal signals.
[0025] PARK transformation: namely Park's Transform, which is a coordinate transformation method proposed by engineer R.H. Park, aiming to convert the stationary coordinate system (αβ) into the coordinate system (dq) rotating synchronously with the rotor, realizing decoupling and direct current control of alternating current signals, which is originally used for synchronous motor analysis and has been extended to the field of inverter control.
[0026] Notch filter: a filter that can rapidly attenuate the input signal at a certain frequency point to achieve the filtering effect of hindering the passage of signals at this frequency. The notch filter belongs to a kind of band-stop filter, and its stop band is very narrow, and the order must be two or more.
[0027] Bilinear transformation method: a digital signal processing technique used to convert the transfer function of a continuous-time system (s domain) into a discrete-time system (z domain) transfer function, so as to use analog filter design methods to design digital filters.
[0028] Optionally, the inverter control method under nonlinear load provided by each embodiment of the present application can be integrated into an electronic device with control function, such as an embedded controller, an industrial control terminal, a server or an upper computer system for running control logic. It should be understood that the present application does not limit the specific type of the electronic device, as long as it can execute the steps included in the above control method, it belongs to the protection scope of the present application.
[0029] Reference Figure 2 is a flowchart of an inverter control method under nonlinear load provided by an embodiment of the present application. The inverter control method comprises: Step S101, obtaining the voltage signal and current signal of the output end of the inverter, and converting the voltage signal and current signal into components in the rotating coordinate system.
[0030] In step S101, the voltage signal and the current signal are acquired in real time at the output end of the inverter, and the acquired voltage signal and current signal are sequentially subjected to orthogonal signal generation and rotating coordinate transformation, so that components in the rotating coordinate system suitable for inverter current / voltage double-loop PI control are obtained.
[0031] Specifically, first, the voltage signal and the current signal are respectively input into a second-order generalized integrator to generate a set of orthogonal signal components corresponding to the voltage signal and the current signal, i.e., α component and β component. Subsequently, the α component and the β component of the voltage signal and the α component and the β component of the current signal are respectively subjected to PARK transformation, and the orthogonal signal components are mapped to the synchronous rotating coordinate system to obtain a set of components in the rotating coordinate system corresponding to the voltage signal and the current signal, i.e., D component and Q component.
[0032] In step S102, based on at least one target harmonic order obtained by measuring the nonlinear load, the target harmonic order in the components in the rotating coordinate system obtained by converting the current signal is subjected to filtering processing to obtain filtered components in the rotating coordinate system.
[0033] In step S102, first, the nonlinear load driven by the inverter is subjected to harmonic analysis, the high-order harmonic components generated in the operation process are acquired, and at least one harmonic order is determined as a target harmonic order. In implementation, after the current signal at the output end of the inverter is acquired, a power analyzer, a spectrum analyzer or other harmonic measurement equipment can be used to perform spectrum analysis on the current signal at the output end of the inverter, identify the harmonic order with high amplitude, and determine the harmonic order generated by the nonlinear load, such as third harmonic (N=3), fifth harmonic (N=5), etc. One or more determined harmonic orders are used as target harmonic orders for subsequent design and parameter configuration of the notch filter.
[0034] After the target harmonic order is determined, for each target harmonic order, a notch filter for suppressing the harmonic component corresponding to each target harmonic order is designed, and the target harmonic order and the notch filter are set one by one. The components in the rotating coordinate system obtained by converting the current signal are respectively input into a plurality of notch filters for different target harmonic orders and subjected to discretization processing. The discretization processing of the notch filter is to convert the expression form of the notch filter constructed in the continuous time domain into a discrete time domain form that can be executed in a digital control system. After the notch filter filtering processing, the components in the rotating coordinate system of the filtered current signal are obtained, i.e., D' component and Q' component.
[0035] In one possible embodiment, the application adopts a bilinear transformation method to discretize the notch filter. The bilinear transformation method realizes mapping from the continuous time domain to the discrete time domain through variable replacement to meet the requirements of the digital controller on the filter format. The notch filter filters out the interference signals of the corresponding harmonic components respectively, and the processing procedure is as follows: The transfer function of the notch filter is shown in equation (1): Equation (1) where s is a continuous time domain variable, is the center frequency of the notch filter, is the damping ratio, usually taking a value of 0.707.
[0036] First, based on the fundamental frequency of the voltage at the output end of the inverter and the target harmonic order, the center frequency of the notch filter corresponding to each target harmonic order is calculated as shown in equation (2): Equation (2) where is the current target harmonic order, is the center frequency of the notch filter corresponding to the current target harmonic order.
[0037] It should be noted that the essence of the PARK transformation is to map the alternating current signals in the stationary coordinate system to the synchronous rotating coordinate system at the fundamental frequency, so that the fundamental component is converted into a direct current, and the harmonic component is converted into an alternating current at a higher frequency. For a rotating coordinate system with a frequency of , the difference between the frequency of the input signal and the rotating speed determines the frequency of the transformed signal. If the voltage at the output end of the inverter has a fundamental frequency of , and the input signal contains a harmonic order of , i.e., a signal with a frequency of , then the PARK transformation relationship is shown in equation (3): Equation (3) where when the above PARK transformation is performed on the harmonic signal with a frequency of , it is equivalent to rotating the reference frame at an angular speed of . According to the frequency difference principle, the harmonic order of will become an alternating current signal with a frequency of in the transformed result. Therefore, in the rotating coordinate system, to filter out the harmonic order of , a notch filter needs to be designed to suppress signals with a frequency of .
[0038] After calculating the center frequency of the notch filter, based on the set operating period of the notch filter, the continuous time domain variable in the notch filter is calculated using the bilinear transformation calculation formula Convert to discrete time domain variable The bilinear transformation calculation formula is shown in formula (4): Formula (4) Wherein, is the operating period set for the notch filter.
[0039] Then, formula (4) is brought into formula (1), and according to the variable conversion result, the continuous time transfer function of the notch filter is mapped to the corresponding discrete time transfer function, and based on the obtained discrete time transfer function, the difference equation of the notch filter in the discrete time domain is constructed as shown in formula (5): Formula (5) Wherein, , Z-transform of the input signal and the output signal respectively, , Z-transform of the input signal and the output signal delayed by one sampling period respectively, , Z-transform of the input signal and the output signal delayed by two sampling periods respectively, , , , , , All are difference equation coefficients, the coefficients of the difference equation are determined by the center frequency, the damping ratio and the sampling period of the notch filter, and are used to realize the filtering of the target harmonic number in the discrete time domain, and the specific calculation formula of the difference equation coefficient is shown in formula (6): ; ; ; Formula (6) ; ; ; In addition, as preferred, the design of the filter in the application is only based on the parameters that can be directly obtained or set, such as target harmonic order, damping ratio and sampling period, avoiding complex system modeling and parameter setting, and having the advantages of simple algorithm implementation and convenient engineering application. At the same time, the design parameters of the notch filter are not pre-fixed or statically set, but dynamically generated based on the real-time measurement results of the harmonic characteristics of the current driven nonlinear load. Specifically, first, the main harmonic orders (such as third, fifth, seventh, etc.) existing in the signal are identified according to the current signal at the output end of the inverter and combined with the frequency spectrum analysis means, and then the target harmonic order set is determined according to the identification result. On this basis, the center frequency of the notch filter corresponding to each target harmonic order is dynamically calculated, and the corresponding discrete-time domain notch filter difference equation is constructed based on the bilinear transformation method. The above-mentioned notch filter is finally embedded in the current loop control path of the inverter, and only the high-amplitude harmonics actually measured are suppressed, so as to avoid blind filtering of non-critical frequencies, improve the filtering efficiency and reduce the influence on the normal control dynamic performance.
[0040] In step S103, the D and Q components in the rotating coordinate system obtained by converting the voltage signal and the D' and Q' components in the rotating coordinate system after the current signal is filtered to remove the target harmonic order are input to the inverter controller as feedback signals, and a control signal for adjusting the output voltage of the inverter is generated.
[0041] In step S103, the D and Q components in the rotating coordinate system obtained by converting the voltage signal and the D' and Q' components in the rotating coordinate system after the current signal is filtered to remove the target harmonic order are input to the inverter controller as feedback signals, and a control signal for adjusting the output voltage of the inverter is generated.
[0042] At the same time, since the voltage signal does not participate in the filtering process, the original voltage control loop remains unchanged, and the filtering process only acts on the current feedback channel and does not destroy the stability of the double closed-loop control system. Therefore, the scheme can be directly embedded in the existing control architecture for deployment, without the need to adjust the main control logic or parameter configuration of the existing controller, and has good portability and product upgrade compatibility.
[0043] In summary, the above-mentioned scheme has the advantages of Figure 3The voltage signal and the current signal are converted into components in a rotating coordinate system, the components of the voltage signal are directly used in a voltage control loop without filtering in a control strategy, the components of the current signal are filtered at a target harmonic number, and finally, the filtered current signal components and the unfiltered voltage signal components are input into an inverter controller. Compared with the conventional solution in which the voltage and the current signal are uniformly processed, the voltage signal and the current signal are first decoupled and processed in the solution, the filtering operation is only performed on the target harmonic component in the current signal, and the original form of the voltage signal component is retained. The solution not only effectively weakens the interference of the current feedback harmonic caused by the nonlinear load on the controller performance, reduces the control deviation, and makes the inverter output voltage close to an ideal sinusoidal waveform, but also avoids changing the voltage control loop structure, thereby ensuring the control stability of the system. The control method in which the filtering operation is limited to the current channel rather than uniformly performed on all feedback paths breaks the conventional thinking of symmetrical filtering or overall compensation in the control structure design of the person skilled in the art, and helps to improve the sinusoidal waveform quality of the inverter output voltage without increasing the system complexity.
[0044] Moreover, the inverter control method provided in the solution effectively suppresses the harmonic interference introduced by the nonlinear load by adding a current signal filtering step based on a target harmonic number based on the existing voltage signal and current signal. Compared with the conventional solution that relies on an external filter or an additional sampling module, the filter used in the solution is a notch structure realized in the control system, without introducing an additional physical filter or hardware module, and without introducing additional hardware costs.
[0045] Figure 4 is a structural block diagram of an inverter control system under a nonlinear load provided by an embodiment of the solution, and the system at least includes the following modules: A signal conversion module is configured to obtain a voltage signal and a current signal at an output end of an inverter, and convert the voltage signal and the current signal into components in a rotating coordinate system. A signal filtering module is configured to filter a target harmonic number in the components in the rotating coordinate system obtained by converting the current signal based on at least one target harmonic number obtained by analyzing the load characteristics, to obtain filtered components in the rotating coordinate system. A signal integration module is configured to input the components in the rotating coordinate system obtained by converting the voltage signal and the filtered components in the rotating coordinate system of the current signal into an inverter controller, to generate a control signal for adjusting the output voltage of the inverter.
[0046] For related details, refer to the above method embodiments.
[0047] Figure 5is a block diagram of an electronic device provided by an embodiment of the present application, which may, in some embodiments, be an embedded system or an industrial control device with inverter control function. The device includes at least a processor 501 and a memory 502.
[0048] The processor 501 is configured to execute algorithms and logical operations related to inverter control. The processor 501 may, for example, be a hardware platform with real-time control capability, such as a digital signal processor (DSP), a field programmable gate array (FPGA), or a system on chip (SoC). The processor 501 may, for example, include one or more processing cores configured to perform sampling, transformation, filtering, and control signal generation on inverter output signals to meet the control requirements of the inverter in a nonlinear load environment.
[0049] The memory 502 may, for example, include one or more computer-readable storage media that may, for example, be non-transitory. The memory 502 may, for example, further include a high-speed random access memory and a non-volatile memory such as one or more disk storage devices, flash storage devices. In some embodiments, the non-transitory computer-readable storage medium in the memory 502 is configured to store at least one instruction for execution by the processor 501 to implement the inverter control method in a nonlinear load environment provided by the method embodiments of the present application.
[0050] In some embodiments, the electronic device may, for example, further include a peripheral device interface and at least one peripheral device. The processor 501, the memory 502, and the peripheral device interface may, for example, be connected by a bus or a signal line. Each peripheral device may, for example, be connected to the peripheral device interface by a bus, a signal line, or a circuit board. The peripheral devices may, for example, include but are not limited to radio frequency circuitry, a touch display screen, audio circuitry, a power supply, and the like.
[0051] Of course, the electronic device may, for example, further include fewer or more components, which are not limited in the present embodiment.
[0052] Optionally, the present application further provides a computer-readable storage medium having a program stored therein, which is loaded and executed by a processor to implement the inverter control method in a nonlinear load environment provided by the method embodiments described above.
[0053] Optionally, the present application further provides a computer product including a computer-readable storage medium having a program stored therein, which is loaded and executed by a processor to implement the inverter control method in a nonlinear load environment provided by the method embodiments described above.
[0054] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, any combination of these technical features is considered to be within the scope of the present disclosure.
[0055] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these are within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims
1. An inverter control method under nonlinear load, characterized in that, The method includes: Acquire the voltage and current signals at the output of the inverter, and convert the voltage and current signals into components in a rotating coordinate system; Based on at least one target harmonic number obtained from the measurement of the nonlinear load, the target harmonic number in the component of the rotating coordinate system obtained by the conversion of the current signal is filtered to obtain the filtered component in the rotating coordinate system. The components of the voltage signal converted into rotating coordinates and the components of the current signal filtered into rotating coordinates are input to the inverter controller to generate a control signal for adjusting the inverter output voltage.
2. The inverter control method under nonlinear load according to claim 1, characterized in that, The step of filtering the target harmonic number in the rotating coordinate system component obtained by converting the current signal based on at least one target harmonic number obtained from nonlinear load measurement, to obtain the filtered rotating coordinate system component includes: Measure the harmonic order generated by the nonlinear load and determine at least one harmonic order as the target harmonic order; For each target harmonic order, a notch filter is designed to suppress the corresponding harmonic component, and the target harmonic order corresponds one-to-one with the notch filter; The notch filter is discretized using a bilinear transformation method. All discretized notch filters are then applied to the components in the rotating coordinate system obtained by converting the current signal to filter the target harmonic order.
3. The inverter control method under nonlinear load according to claim 2, characterized in that, The notch filter designed to suppress the corresponding harmonic component for each target harmonic order includes: Based on the base frequency of the inverter output voltage Based on the target harmonic order, the center frequency of the notch filter is calculated as follows: ； in, The center frequency of the notch filter is... The target harmonic order.
4. The inverter control method under nonlinear load according to claim 3, characterized in that, The discretization process of the notch filter using the bilinear transform method includes: Based on the set sampling period, the continuous time domain variables in the notch filter are converted into discrete time domain variables using the bilinear transformation calculation formula. Based on the variable transformation result, the continuous-time transfer function of the notch filter is mapped to the corresponding discrete-time transfer function; based on the discrete-time transfer function, a difference equation in the discrete-time domain is constructed. The coefficients of the difference equation are determined by the center frequency, damping ratio, and sampling period of the notch filter, and are used to filter out the target harmonic order in the discrete time domain.
5. The inverter control method under nonlinear load according to claim 2, characterized in that, The step of applying all discretized notch filters to the components in the rotating coordinate system obtained by converting the current signal, and filtering the target harmonic order, includes: The components of the current signal in the rotating coordinate system are input into multiple notch filters that are discretized for different target harmonic orders. The notch filters filter out the interference signals of the corresponding harmonic components to obtain the components of the current signal in the rotating coordinate system after filtering.
6. The inverter control method under nonlinear load according to claim 1, characterized in that, After acquiring the voltage and current signals at the inverter output, the process further includes: The voltage and current signals at the output of the inverter are acquired, and the voltage and current signals are respectively input into a second-order generalized integrator to generate orthogonal signal components corresponding to the voltage and current signals.
7. The inverter control method under nonlinear load according to claim 6, characterized in that, After generating the orthogonal signal components corresponding to the voltage signal and the current signal respectively, the process further includes: The orthogonal signal components corresponding to the voltage signal and the current signal are converted into components in a rotating coordinate system through PARK transformation.
8. An inverter control system under nonlinear load, characterized in that, include: The signal conversion module is used to acquire the voltage and current signals at the output of the inverter and convert the voltage and current signals into components in a rotating coordinate system. The signal filtering module is used to filter the target harmonic number in the rotating coordinate system component obtained by converting the current signal based on at least one target harmonic number obtained by measuring the nonlinear load, so as to obtain the filtered rotating coordinate system component. The signal integration module is used to input the rotating coordinate system component of the voltage signal and the rotating coordinate system component of the current signal after filtering to the inverter controller to generate a control signal for adjusting the inverter output voltage.
9. An electronic device, characterized in that, The device includes a processor and a memory; the memory stores a program that is loaded and executed by the processor to implement an inverter control method under a nonlinear load as described in any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, The storage medium stores a program that, when executed by a processor, is used to implement an inverter control method under a nonlinear load as described in any one of claims 1 to 7.