A harmonic suppression method, device, electronic device and storage medium

Abstract

The present invention discloses a harmonic suppression method, device, electronic device and storage medium, which relates to the field of harmonic suppression. The harmonics present in the current PCC voltage are determined by making a phase-by-phase difference between the PCC voltage of the isolated microgrid and the ideal target voltage, which can not only extract the integer harmonics, but also effectively determine the interharmonic components with unknown harmonic frequencies. The entire feedforward compensation process is able to reduce the impedance of the virtual synchronous generator within a wide band, reducing the voltage drop of the harmonic current introduced by the nonlinear load on the impedance of the virtual synchronous generator, thereby effectively suppressing integer harmonics and interharmonics with unknown frequencies, and achieving the effect of wide-band harmonic suppression. The entire control method achieves harmonic suppression by adjusting the three-phase voltage modulation wave of the virtual synchronous generator, does not require the addition of any additional hardware equipment, and has excellent economy.

Description

Technical Field

[0001] The present invention relates to the field of harmonic suppression, and in particular to a harmonic suppression method, device, electronic equipment and storage medium. Background Art

[0002] Island microgrids can absorb renewable energy locally and meet the decentralized power supply needs of remote areas, playing an important role in modern power systems. At the same time, VSG (virtual synchronous generator) control can provide the necessary inertia and damping support for island microgrids, improving voltage and frequency stability. Therefore, the number of island microgrids based on VSG technology is gradually increasing, and the development is becoming more and more extensive. However, with the gradual increase in the penetration rate of nonlinear loads, there are still serious harmonic problems in island microgrids based on VSG technology. Nonlinear loads will bring serious harmonic problems to island microgrids, reduce the quality of power, and affect their safe and stable operation. How to suppress the harmonics caused by nonlinear loads has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide a harmonic suppression method, device, electronic device and storage medium, which can effectively suppress integer harmonics and interharmonics of unknown frequency, achieve the effect of wide-band harmonic suppression, and achieve harmonic suppression by improving the control algorithm of the virtual synchronous generator. It does not require the addition of any additional hardware equipment and has excellent economy.

[0004] In order to solve the above technical problems, the present invention provides a harmonic suppression method, comprising:

[0005] The current PCC voltage of the island microgrid is subtracted from the ideal target voltage phase by phase to obtain the harmonic voltage;

[0006] Determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in the island microgrid based on the harmonic voltage;

[0007] Performing feedforward compensation on the current three-phase voltage modulation wave by using the feedforward compensation amount to obtain a target three-phase voltage modulation wave;

[0008] The target three-phase voltage modulation wave is used to control the power switch tube in the virtual synchronous generator.

[0009] Optionally, also include:

[0010] Obtaining the current rated output voltage of the virtual synchronous generator and the phase angle of the current three-phase voltage modulation wave;

[0011] Calculating the ideal target voltage of the virtual synchronous generator based on the current rated output voltage and the phase angle of the current three-phase voltage modulation wave;

[0012] The calculation formula of the ideal target voltage is:

[0013] ;

[0014] in, is the rated output voltage of the virtual synchronous generator, is the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator.

[0015] Optionally, obtaining the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator includes:

[0016] Obtaining the active power reference value of the virtual synchronous generator, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power;

[0017] Calculating the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator based on the active power reference value, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power;

[0018] The calculation formula of the phase angle of the current three-phase voltage modulation wave is:

[0019] ;

[0020] in, is the active power reference value of the virtual synchronous generator, is the instantaneous active power of the virtual synchronous generator, is the rated angular frequency of the output voltage of the virtual synchronous generator, is the active damping coefficient of the virtual synchronous generator, ,and is the virtual moment of inertia of the virtual synchronous generator.

[0021] Optionally, determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the harmonic voltage includes:

[0022] Determining the product of the harmonic voltage and a preset feedforward coefficient;

[0023] A feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator is determined based on the product.

[0024] Optionally, determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the product includes:

[0025] Controlling the product to be input into a first-order low-pass filter;

[0026] A feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator is determined based on an output signal of the first-order low-pass filter.

[0027] Optionally, determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on an output signal of the first-order low-pass filter comprises:

[0028] Performing delay compensation on the output signal of the first-order low-pass filter;

[0029] The output signal after delay compensation is used as a feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator.

[0030] Optionally, determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the harmonic voltage includes:

[0031] Inputting the harmonic voltage into a feedforward compensation controller to obtain a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator;

[0032] The transfer function of the feedforward compensation controller is:

[0033] ;

[0034] in, is the transfer function of the feedforward compensation controller, is the differential operator, is the preset feedforward coefficient, is the cut-off frequency of the first-order low-pass filter.

[0035] In order to solve the above technical problems, the present invention further provides a harmonic suppression device, comprising:

[0036] A harmonic determination unit is used to perform phase-by-phase subtraction between the current PCC voltage of the island microgrid and the ideal target voltage to obtain a harmonic voltage;

[0037] A feedforward compensation amount determination unit, configured to determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in the island microgrid based on the harmonic voltage;

[0038] A compensation unit, configured to perform feedforward compensation on the current three-phase voltage modulation wave by using the feedforward compensation amount to obtain a target three-phase voltage modulation wave;

[0039] A control unit is used to control the power switch tube in the virtual synchronous generator using the target three-phase voltage modulation wave.

[0040] In order to solve the above technical problems, the present invention further provides an electronic device, comprising:

[0041] Memory for storing computer programs;

[0042] A processor is used to implement the steps of the harmonic suppression method as described above.

[0043] In order to solve the above technical problem, 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 harmonic suppression method as described above are implemented.

[0044] The present invention provides a harmonic suppression method, which determines the harmonics present in the current PCC voltage by making a phase-by-phase difference between the PCC voltage of the isolated microgrid and the ideal target voltage, and can not only extract the integer harmonics therein, but also effectively determine the interharmonic components with unknown harmonic frequencies. The entire feedforward compensation process is able to reduce the impedance of the virtual synchronous generator within a wide band, reducing the voltage drop of the harmonic current introduced by the nonlinear load on the impedance of the virtual synchronous generator, thereby effectively suppressing integer harmonics and interharmonics with unknown frequencies, and achieving the effect of wide-band harmonic suppression. The entire control method achieves harmonic suppression by adjusting the three-phase voltage modulation wave of the virtual synchronous generator. The adjustment of the three-phase voltage modulation wave of the virtual synchronous generator can be achieved directly by improving the control algorithm of the virtual synchronous generator, without adding any additional hardware equipment, and has excellent economy.

[0045] The present invention also provides a harmonic suppression device, an electronic device and a computer-readable storage medium, which have the same beneficial effects as the above-mentioned harmonic suppression method. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the prior art and the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of a flow chart of a harmonic suppression method provided by the present invention;

[0048] Figure 2 A schematic diagram of the structure of an isolated microgrid system based on VSG provided by the present invention;

[0049] Figure 3A schematic diagram showing the comparison of the VSG impedance before and after the harmonic suppression method provided by the present invention is implemented;

[0050] Figure 4 A schematic diagram of the waveform of the PCC voltage of the island microgrid under the 100% rectified load condition provided by the present invention when the harmonic suppression method is not implemented;

[0051] Figure 5 It is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid under the 100% rectified load condition provided by the present invention when the harmonic suppression method is not implemented;

[0052] Figure 6 A schematic diagram of the waveform of the PCC voltage of the isolated island microgrid after implementing the harmonic suppression method under the 100% rectified load condition provided by the present invention;

[0053] Figure 7 This is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated island microgrid after implementing the harmonic suppression method under the 100% rectified load condition provided by the present invention;

[0054] Figure 8 A schematic diagram of the waveform of the PCC voltage of the island microgrid under the 100% pulse load condition provided by the present invention when the harmonic suppression method is not implemented;

[0055] Fig. 9 It is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated island microgrid under the 100% pulse load condition provided by the present invention when the harmonic suppression method is not implemented;

[0056] Fig.10 A schematic diagram of the waveform of the PCC voltage of the isolated island microgrid after implementing the harmonic suppression method under the 100% pulse load condition provided by the present invention;

[0057] Fig.11 This is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid after implementing the harmonic suppression method under the 100% pulse load condition provided by the present invention;

[0058] Fig.12 A schematic diagram of the structure of a harmonic suppression device provided by the present invention;

[0059] Fig.13 The present invention provides a schematic structural diagram of an electronic device. DETAILED DESCRIPTION

[0060] The core of the present invention is to provide a harmonic suppression method, device, electronic device and storage medium, which can effectively suppress integer harmonics and interharmonics of unknown frequency, achieve the effect of wide-band harmonic suppression, and achieve harmonic suppression by improving the control algorithm of the virtual synchronous generator. It does not require the addition of any additional hardware equipment and has excellent economy.

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0062] Nonlinear loads can cause serious harmonic problems in isolated microgrids, reduce the quality of electric energy, and affect their safe and stable operation. In particular, among nonlinear loads, there is a type of nonlinear load with pulse characteristics (i.e., pulse loads), such as adjustable speed devices, etc., which are different from the integer harmonics generated by nonlinear rectifier loads. Pulse loads will generate interharmonics with frequencies that are non-integer multiples of the fundamental frequency in isolated microgrids, and their harmonic frequencies are related to the pulse frequency. Since the pulse frequency is time-varying and difficult to predict in advance, the time-varying interharmonics generated by the pulse load and the integer harmonics generated by the rectifier load will make the voltage harmonics present a wide-band characteristic, which seriously affects the stable operation of the isolated microgrid. However, the traditional harmonic suppression strategy in the prior art can only suppress integer harmonics with relatively fixed harmonic frequencies, but it is difficult to effectively suppress the interharmonics caused by pulse loads and achieve wide-band harmonic suppression.

[0063] With the development of power electronics technology, the penetration rate of pulse loads in isolated island microgrids has gradually increased. In some special isolated island microgrids, such as ship microgrid systems, the proportion of pulse loads will be further increased. The time-varying interharmonics generated by these pulse loads will seriously reduce the power quality of the isolated island microgrid and affect the safety of electrical equipment. Therefore, the present invention discloses a wide-frequency voltage harmonic suppression method for an isolated island microgrid based on VSG, which can simultaneously suppress integer harmonics caused by nonlinear rectifier loads and interharmonics caused by nonlinear pulse loads, achieve wide-band harmonic suppression, and thus significantly improve the power quality of the isolated island microgrid. At the same time, it does not require any additional hardware equipment, and has good economy. The specific implementation method is described as follows.

[0064] Please refer to Figure 1 , Figure 1 A schematic diagram of a harmonic suppression method provided by the present invention; please refer to Figure 2 , Figure 2The present invention provides a schematic diagram of the structure of an isolated microgrid system based on VSG. To solve the above technical problems, the present invention provides a harmonic suppression method, comprising:

[0065] S11: Subtract the current PCC (point of the common coupling) voltage of the island microgrid from the ideal target voltage phase by phase to obtain the harmonic voltage.

[0066] It is not difficult to understand that in order to achieve harmonic suppression in the isolated microgrid system, it is necessary to first determine the harmonics in the isolated microgrid. VSG is connected to the distribution network through PCC, and the distribution network is then connected to various types of loads to form an isolated microgrid system. As a power generation device in the isolated microgrid system, VSG will output voltage to the PCC in the isolated microgrid system to realize the power supply and distribution process of the connected loads. When controlling the output voltage of VSG, it is hoped that the output voltage of VSG can always be maintained at a standard sine wave, that is, the standard sine wave is used as the ideal target voltage of the VSG output voltage when controlling VSG. However, due to the presence of nonlinear loads, the voltage of the isolated microgrid will be distorted, so that the output voltage of VSG cannot be maintained as a standard sine wave. Therefore, in this application, the ideal target voltage under this ideal condition is used to determine the harmonics in the current PCC voltage, and the current PCC voltage of the isolated microgrid is subtracted from the ideal target voltage phase by phase to obtain the harmonic components existing in the PCC voltage.

[0067] It should be noted that the phase-by-phase difference between the current PCC voltage and the ideal target voltage refers to the difference between the A-phase voltage in the current PCC voltage and the A-phase voltage of the ideal target voltage, the difference between the B-phase voltage in the current PCC voltage and the B-phase voltage of the ideal target voltage, and the difference between the C-phase voltage in the current PCC voltage and the C-phase voltage of the ideal target voltage; by making such phase-by-phase differences, the difference between the actual output voltage and the theoretical ideal voltage can be effectively determined, so that the final harmonic voltage can represent all harmonics in the current output voltage. The specific method of obtaining the current PCC voltage and the ideal target voltage is not particularly limited in this application. The current PCC voltage can be directly achieved by sampling the voltage output by the VSG, which can be achieved by detection devices such as voltage sensors.

[0068] S12: Determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in the island microgrid based on the harmonic voltage.

[0069] It can be understood that after the harmonic voltage is determined, the three-phase voltage modulation wave of the VSG can be compensated based on the determined harmonic voltage. The three-phase voltage modulation wave of the VSG refers to the modulation signal input to the VSG for generating the output voltage. The three-phase voltage modulation wave is input to the VSG, which can control the switching state of the power switch tube therein, thereby generating the required three-phase voltage. The current three-phase voltage modulation wave refers to the modulation wave currently input to the VSG, which enables the VSG to generate the current PCC voltage. Under the action of the current three-phase voltage modulation wave, the harmonic voltage exists in the PCC voltage. Therefore, by using this harmonic voltage to compensate and correct the three-phase voltage modulation wave, the VSG can output a normal PCC voltage that does not contain the harmonic voltage under the action of the corrected target three-phase voltage modulation wave. Correspondingly, the current PCC voltage refers to the voltage output by the VSG to the PCC point in the isolated microgrid under the action of the current three-phase voltage modulation wave, which corresponds to the current three-phase voltage modulation wave. The present application does not impose any particular limitation on the specific method for determining the feedforward compensation amount, and the amount can be obtained by transforming the harmonic voltage after the harmonic voltage is obtained.

[0070] S13: Using the feedforward compensation amount to perform feedforward compensation on the current three-phase voltage modulation wave to obtain a target three-phase voltage modulation wave.

[0071] It is not difficult to understand that the harmonic voltage generated by the current three-phase voltage modulation wave can be offset by feedforward compensation. Therefore, in general, the current three-phase voltage modulation wave needs to be subtracted from the feedforward compensation amount, and the harmonic voltage generated by the modulation wave control can be offset by the feedforward compensation process. Specifically, the target three-phase voltage modulation wave can be obtained by subtracting the current three-phase voltage modulation wave from the feedforward compensation amount phase by phase.

[0072] S14: Using the target three-phase voltage modulation wave to control the power switch tube in the virtual synchronous generator.

[0073] It is understandable that the final target three-phase voltage modulation wave will be input into the VSG to control the power switch tube therein to perform switching action, thereby generating a corresponding output voltage. At the same time, since the target three-phase voltage modulation wave is a corrected three-phase voltage modulation wave after feedforward compensation, under the action of the target three-phase voltage modulation wave, the harmonic voltage is eliminated from the voltage finally output by the VSG, and the ideal target voltage is approximately reached, achieving accurate and reliable power supply. This application does not make any special restrictions on the specific types and implementation methods of the VSG, the power grid, and the loads connected to the VSG. Figure 2As shown, the load includes a linear load and a nonlinear load, and the nonlinear load includes a rectifier load and a pulse load. The harmonic suppression method provided by the present invention can be directly multiplexed in a controller for generating a three-phase voltage modulation wave, or a separate controller can be set to cooperate with the controller for generating a three-phase voltage modulation wave to realize the harmonic suppression process.

[0074] The present invention provides a method for suppressing broadband voltage harmonics in an isolated microgrid based on VSG, which can be used to suppress broadband voltage harmonics caused by nonlinear loads. The theoretical ideal three-phase ideal target voltage Make a difference phase by phase to calculate the harmonic voltage in the isolated microgrid in real time The harmonic voltage can be controlled later. , the feedforward compensation value of the proposed broadband harmonic suppression method is obtained through the feedforward compensation controller and the delay compensation link The three-phase voltage modulation wave that originally controls the VSG The feedforward compensation obtained previously Perform phase-by-phase subtraction to obtain the improved and corrected three-phase modulation signal of VSG , so that the corrected target three-phase voltage modulation wave is used for PWM modulation to control the on and off of the switch tube to achieve the suppression of broadband harmonics.

[0075] It should be noted that in order to suppress the voltage harmonics caused by nonlinear loads, the present invention proposes a broadband voltage harmonic suppression method for an isolated microgrid based on VSG. The method realizes harmonic suppression by improving the control algorithm of VSG, ensuring the safe and stable operation of all electrical equipment in the system, and does not require the addition of any additional hardware equipment, and has excellent economy. At the same time, the present invention determines the harmonic voltage in the voltage by making a difference phase by phase, which can not only suppress integer harmonics with known harmonic frequencies, but also suppress interharmonic components with unknown harmonic frequencies. Thereby, the impedance of VSG can be reduced within a wide band, the voltage drop of the harmonic current introduced by the nonlinear load on the impedance of VSG is reduced, and integer harmonics and interharmonics with unknown frequencies can be effectively suppressed, achieving the effect of broadband harmonic suppression. The harmonic suppression method provided by the present invention can not only be applied in the control process of VSG, but also can be applied to control fields such as other types of power electronic converters.

[0076] As a specific embodiment, there are usually multiple power sources in an isolated microgrid to supply power to the load, so this embodiment is described by taking an isolated microgrid system with two VSGs in parallel as a specific example. However, the harmonic suppression method provided by the present invention is actually applicable to an isolated microgrid composed of any number of power sources and energy storage devices, and is not limited to an isolated microgrid composed of two VSGs in parallel. Figure 2 As shown in the figure, there are two VSGs, VSG1 and VSG2, in the isolated microgrid, and each VSG adopts the same topology and control algorithm. Since the implementation process of the harmonic suppression method in each VSG is exactly the same, Figure 2 Only a single VSG in the isolated microgrid, namely VSG2, is used for illustration. Figure 2 Only the control block diagram of VSG2 and the corresponding harmonic suppression method are drawn. The control block diagram of VSG1 and the corresponding harmonic suppression method can be set with reference to VSG2, and this application will not repeat them here. When the line impedance is ignored, the VSG output voltage is the PCC voltage. Among them, the superscript of the parameter indicates which VSG the parameter belongs to, such as Indicates the output voltage of the first VSG; represents the inductor current of the first VSG, Indicates the output voltage of the second VSG; Represents the inductor current of the second VSG. Indicates the DC side voltage; a filter is also set at the output end of the VSG, and the filter adopts an LC filter. represents the filter inductance of the filter, Represents the filter capacitance of the filter, Represents the damping resistance of the filter. VSG is connected to the linear load, rectifier load, and pulse load through PCC. represents the resistance of the linear load, represents the resistance of the rectifier load, Represents the resistance of the pulse load; Indicates the pulse frequency of the pulse load; Indicates the impedance of VSG.

[0077] It should be noted that since the nonlinear load can be approximately equivalent to a harmonic current source, the harmonic current it generates will produce a corresponding harmonic voltage drop on the internal impedance of the VSG, thereby causing voltage distortion in the PCC of the isolated microgrid. Obviously, by reducing the impedance amplitude of the VSG in the harmonic frequency band, the voltage harmonics of the isolated microgrid can be effectively suppressed. Based on this principle, the sequential impedance modeling method can be used to establish impedance models before and after the implementation of the proposed harmonic suppression method, respectively, to intuitively demonstrate and verify the harmonic suppression effect of the present invention. It can be calculated that the VSG impedance model before and after the implementation of the harmonic suppression method provided by the present invention and The expressions are:

[0078] ;

[0079] ;

[0080] in, is a natural constant, is an imaginary unit; , Represents the cutoff angular frequency of the current sampling filter; . Represents the cutoff frequency of the voltage sampling filter; represents the inverter gain, and , Indicates the fundamental amplitude of the PCC voltage; represents the fundamental amplitude of the inductor current, It represents the initial phase angle of the inductor current; Indicates the fundamental frequency; is the rated angular frequency of the VSG output voltage; ,in represents the power angle of VSG, and . is the rated RMS value of the VSG output voltage, ; is the virtual moment of inertia, is the active damping coefficient. Please refer to Figure 3 , Figure 3 A schematic diagram of the comparison of the VSG impedance before and after the implementation of the harmonic suppression method provided by the present invention; the shaded area in the figure is the 100Hz-1000Hz frequency band, and the broadband harmonics caused by the load in the isolated microgrid are mainly concentrated in this frequency band. It can be seen from the figure that after adopting the harmonic suppression method provided by the present invention, the impedance at all frequency points in the harmonic frequency region can be effectively reduced, thereby reducing the harmonic voltage drop of the harmonic current on the VSG impedance and achieving broadband harmonic suppression.

[0081] The present invention provides a harmonic suppression method, which determines the harmonics present in the current PCC voltage by making a phase-by-phase difference between the PCC voltage of the isolated microgrid and the ideal target voltage, and can not only extract the integer harmonics therein, but also effectively determine the interharmonic components with unknown harmonic frequencies. The entire feedforward compensation process is able to reduce the impedance of the virtual synchronous generator within a wide band, reducing the voltage drop of the harmonic current introduced by the nonlinear load on the impedance of the virtual synchronous generator, thereby effectively suppressing integer harmonics and interharmonics with unknown frequencies, and achieving the effect of wide-band harmonic suppression. The entire control method achieves harmonic suppression by adjusting the three-phase voltage modulation wave of the virtual synchronous generator. The adjustment of the three-phase voltage modulation wave of the virtual synchronous generator can be achieved directly by improving the control algorithm of the virtual synchronous generator, without adding any additional hardware equipment, and has excellent economy.

[0082] Based on the above embodiments:

[0083] As an optional embodiment, it also includes:

[0084] Obtaining the current rated output voltage of the virtual synchronous generator and the phase angle of the current three-phase voltage modulation wave;

[0085] Calculate the ideal target voltage of the virtual synchronous generator based on the current rated output voltage and the phase angle of the current three-phase voltage modulation wave;

[0086] The ideal target voltage is calculated as:

[0087] ;

[0088] in, is the rated RMS value of the VSG output voltage, is the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator.

[0089] It is not difficult to understand that the present invention replaces the traditional harmonic extraction process by calculating the harmonic voltage in real time. The calculation process of the harmonic voltage is as follows. First, according to the rated amplitude of the VSG output voltage and the phase angle of the three-phase voltage modulation wave currently controlling the VSG , calculate the ideal three-phase target voltage .in, is the A phase voltage of the three-phase ideal target voltage, is the B phase voltage of the three-phase ideal target voltage, is the C phase voltage of the three-phase ideal target voltage, is the rated RMS value of the VSG output voltage, i.e. the rated output voltage of the virtual synchronous generator, is the phase angle of the current three-phase voltage modulation wave. Then, the sampled PCC voltage The ideal three-phase voltage By making a difference phase by phase, we can get the harmonic voltage , the corresponding harmonic voltages are determined by phase-by-phase subtraction. The resulting harmonic voltage has only a small sinusoidal deviation from the actual voltage harmonic component, which can effectively characterize all harmonics in the current output voltage of the VSG. The expression of harmonic voltage is: .

[0090] Specifically, the rated output voltage corresponding to the current three-phase voltage modulation wave can be directly used to calculate the ideal target voltage corresponding to the current three-phase voltage modulation wave, and the theoretical ideal voltage can be determined by means of rated values, which is accurate and effective.

[0091] As an optional embodiment, obtaining the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator includes:

[0092] Obtaining the active power reference value of the virtual synchronous generator, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power;

[0093] Calculating the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator based on the active power reference value, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power;

[0094] The calculation formula of the phase angle of the current three-phase voltage modulation wave is:

[0095] ;

[0096] in, is the active power reference value of the virtual synchronous generator, is the instantaneous active power of the virtual synchronous generator, is the rated angular frequency of the output voltage of the virtual synchronous generator, is the active damping coefficient, ,and is the virtual moment of inertia.

[0097] It is understandable that the phase angle of the current three-phase voltage modulation wave can be realized by analyzing and calculating the parameters in the traditional control process of the VSG before the harmonic suppression method provided by the present invention is adopted. At the same time, considering the need to perform feedforward compensation on the current three-phase voltage modulation wave in the future, it is also necessary to determine and calculate the current three-phase voltage modulation wave. Among them, the three-phase voltage modulation wave originally controlled by the traditional VSG It can be obtained by following the steps below, where the current and voltage parameters are all in the current three-phase voltage modulation wave Output parameters of VSG under action.

[0098] As a specific embodiment, firstly, the inductor current flowing through the filter inductor connected to the output end of the VSG is sampled. , , and PCC voltage , , Perform instantaneous power calculation to obtain the instantaneous active power of VSG and instantaneous reactive power , the instantaneous active power of VSG and instantaneous reactive power The expression is:

[0099] ;

[0100] in, and is the PCC three-phase voltage , , The value in the αβ coordinate system, and is the three-phase current of the inductor , , Values ​​in the αβ coordinate system.

[0101] Then, according to the classic VSG control algorithm, the amplitude of the current three-phase voltage modulation wave is calculated. Phase Angle , the amplitude of the three-phase voltage modulation wave Phase Angle The expression is:

[0102] ;

[0103] in, is the reference value of VSG active power, is the reference value of VSG reactive power, is the active damping coefficient, is the reactive damping coefficient, is the rated RMS value of the VSG output voltage, is the actual RMS value of the VSG output voltage, is the rated angular frequency of the VSG output voltage, ; is the virtual moment of inertia, ; is the inertia coefficient of the reactive power controller.

[0104] According to the amplitude of the three-phase voltage modulation wave Phase Angle , the three-phase voltage modulation wave of the traditional VSG control can be calculated , , , that is, the current three-phase voltage modulation wave before harmonic suppression is adopted, the current three-phase voltage modulation wave , , The expression is:

[0105] ;

[0106] in, is pi, and cos() is the cosine function. According to the above steps, the current three-phase voltage modulation wave of the traditional VSG control can be obtained. At the same time, the phase angle of the current three-phase voltage modulation wave can also be obtained to determine the ideal three-phase target voltage.

[0107] Specifically, by analyzing and calculating the various parameters of the VSG under the current three-phase voltage modulation wave, the current three-phase voltage modulation wave and the phase angle of the current three-phase voltage modulation wave can be effectively calculated, so as to calculate the ideal three-phase target voltage and use the feedforward compensation to compensate and correct the current three-phase voltage modulation wave.

[0108] As an optional embodiment, determining a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator based on harmonic voltage includes:

[0109] determining a product of a harmonic voltage and a preset feed-forward coefficient;

[0110] A feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator is determined based on the product.

[0111] It is not difficult to understand that the harmonic voltage can be directly used as a feedforward control quantity to compensate the current three-phase voltage modulation wave. However, in order to achieve a better control effect, it is best to multiply the harmonic voltage by a preset feedforward coefficient, and then use the product of the two as the feedforward control quantity to compensate the current three-phase voltage modulation wave. The specific value of the preset feedforward coefficient is not particularly limited in this application, and the preset feedforward coefficient with the best control effect can be obtained through repeated experimental verification or theoretical verification. By changing the feedforward coefficient K c The value of can change the degree of feedforward compensation for the three-phase voltage modulation wave in the harmonic suppression method, thereby obtaining different harmonic suppression effects. Figure 2 The isolated microgrid system shown in Figure 1 takes K c =0.005, the harmonic suppression effect is better and the system has good stability.

[0112] Specifically, by adding a transformation process of multiplying the harmonic voltage by a preset feedforward coefficient, harmonic suppression can adapt to different application situations by changing the preset feedforward coefficient, thereby playing an amplification and optimization role, so that the entire harmonic suppression process can respond to voltage changes and disturbances more accurately and quickly, thereby improving the overall control performance.

[0113] As an optional embodiment, determining the feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator based on the product includes:

[0114] The control product is input to a first-order low-pass filter;

[0115] A feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator is determined based on an output signal of the first-order low-pass filter.

[0116] It is understandable that in addition to increasing the preset feedforward coefficient, a first-order low-pass filter link can be added during the feedforward compensation control process to further transform the harmonic voltage. The signal is further filtered by setting a first-order low-pass filter, and then the output signal of the first-order low-pass filter is used as the feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator, thereby improving the accuracy and reliability of the feedforward compensation amount output in the end. The specific type and implementation method of the first-order low-pass filter are not particularly limited in this application. Since the setting of the preset feedforward coefficient will not only amplify the harmonic voltage, but also amplify the high-frequency noise of the voltage, the first-order low-pass filter link can be used to filter out the high-frequency noise. When the cutoff frequency of the first-order low-pass filter link is The larger the value, the closer the feedforward compensation controller is to the ideal differential controller, making the control performance of the entire feedforward compensation control link better. The best choice for the cutoff frequency is to be set to 4000Hz.

[0117] Specifically, by further adding a first-order low-pass filter in the feedforward compensation link, the accuracy and reliability of the feedforward compensation amount for the final feedforward compensation can be further improved, thereby improving the accuracy and reliability of the entire harmonic suppression process and ensuring the harmonic suppression effect.

[0118] As an optional embodiment, determining the feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator based on the output signal of the first-order low-pass filter includes:

[0119] Perform delay compensation on the output signal of the first-order low-pass filter;

[0120] The output signal after delay compensation is used as a feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator.

[0121] It is not difficult to understand that after obtaining the accurate feedforward compensation amount, the feedforward compensation amount can also be delayed compensated to offset the control delay that may be generated by the entire harmonic suppression method. Therefore, the output signal of the feedforward compensation controller, that is, the output signal of the first-order low-pass filter, can be further input into the delay compensation link for delay compensation, and finally the signal after delay compensation is used as the final feedforward compensation amount to act on the current three-phase voltage modulation wave. The specific setting method of the delay compensation link is not particularly limited in this application. As a specific embodiment, the transfer function of the delay compensation link is The expression is: ;in, is the sampling period of PCC voltage.

[0122] Specifically, control delay can be avoided by further adding a delay compensation link to ensure that the feedforward control amount can act on the corresponding current three-phase voltage modulation wave in a timely and accurate manner, thereby improving the accuracy and reliability of the entire harmonic suppression process.

[0123] As an optional embodiment, determining a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator based on harmonic voltage includes:

[0124] Inputting the harmonic voltage into the feedforward compensation controller to obtain a feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator;

[0125] The transfer function of the feedforward compensation controller is:

[0126] ;

[0127] in, is the transfer function of the feedforward compensation controller, is the differential operator, is the preset feedforward coefficient, is the cut-off frequency of the first-order low-pass filter.

[0128] It can be understood that the feedforward compensation controller of the feedforward compensation process is composed of a differential link and a low-pass filter link. is the transfer function of a first-order low-pass filter; , is the cut-off frequency of the low-pass filter. The feedforward compensation controller further improves the control accuracy of the entire feedforward compensation process by transforming the harmonic voltage through the differential link and the low-pass filter link.

[0129] It should be noted that according to the harmonic voltage , feedforward compensation controller and delay compensation link, the final feedforward compensation amount can be obtained , feedforward compensation The expression is:

[0130] ;

[0131] in, is the transfer function of the feedforward compensation controller; is the transfer function of the delay compensation link. Then, the current three-phase voltage modulation wave that originally controls the VSG is Feedforward compensation Difference is made phase by phase to obtain the target three-phase voltage modulation wave of the improved VSG. Then, according to the target three-phase voltage modulation wave PWM modulation is used to control the on and off of the switch tube in the VSG, thereby achieving a broadband harmonic suppression effect. The target three-phase voltage modulation wave of the improved VSG is The expression is:

[0132] ;

[0133] According to the steps of the previous embodiment, the three-phase voltage modulation wave of the traditional VSG control can be obtained. In addition, according to the above embodiment, the final feedforward compensation amount can be obtained: The above two embodiments provide the three-phase voltage modulation wave of the traditional VSG control. The final feedforward compensation After that, the target three-phase voltage modulation wave of the improved VSG can be obtained by making a difference phase by phase. , thereby performing PWM modulation to control the on and off of the switch tube to achieve broadband voltage harmonic suppression.

[0134] Specifically, the change process of the harmonic voltage can be realized by forming a feedforward compensation controller with a differential link multiplied by the feedforward coefficient and a low-pass filter link of a first-order low-pass filter, and then setting a delay compensation link to perform delay compensation on the output signal of the feedforward compensation controller, so as to output the final accurate and effective feedforward control quantity to act on the current three-phase voltage modulation wave, which is simple, effective and easy to implement.

[0135] As a specific embodiment, please refer to Figure 4 , Figure 4 This is a waveform diagram of the PCC voltage of the island microgrid under the 100% rectified load condition provided by the present invention when the harmonic suppression method is not implemented; please refer to Figure 5 , Figure 5 This is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid under the 100% rectified load condition provided by the present invention when the harmonic suppression method is not implemented; please refer to Figure 6 , Figure 6 This is a waveform diagram of the PCC voltage of the isolated island microgrid after implementing the harmonic suppression method under the 100% rectified load condition provided by the present invention; please refer to Figure 7 , Figure 7 The figure is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid after the harmonic suppression method is implemented under the 100% rectified load condition provided by the present invention; the four figures respectively show the voltage waveforms of the isolated microgrid before and after the harmonic suppression method of the present invention is implemented under the 100% rectified load condition and the corresponding fast Fourier analysis (FFT) analysis results. Figure 4 and Figure 5It can be seen that the rectifier load will generate serious voltage harmonics in the isolated microgrid, and its harmonics are mainly the 5th, 7th, 11th, and 13th harmonics with frequencies that are integer multiples of the fundamental frequency. After the harmonic suppression method of the present invention is implemented, the voltage harmonics caused by the rectifier load are effectively suppressed, and the total harmonic distortion (THD) is reduced from 7.18% before the improvement to 0.69% after the improvement, which shows that the harmonic suppression method provided by the present invention can effectively suppress integer voltage harmonics.

[0136] Please refer to Figure 8 , Figure 8 This is a waveform diagram of the PCC voltage of the island microgrid under the 100% pulse load condition provided by the present invention when the harmonic suppression method is not implemented; please refer to Fig. 9 , Fig. 9 This is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid under the 100% pulse load condition provided by the present invention when the harmonic suppression method is not implemented; please refer to Fig.10 , Fig.10 This is a waveform diagram of the PCC voltage of the isolated microgrid after implementing the harmonic suppression method under the 100% pulse load condition provided by the present invention; please refer to Fig.11 , Fig.11 This is a schematic diagram of the FFT analysis results of the PCC voltage of the isolated microgrid after the harmonic suppression method is implemented under the 100% pulse load condition provided by the present invention; these four figures respectively show the voltage waveforms of the isolated microgrid before and after the implementation of the harmonic suppression method of the present invention under the condition of 100% pulse load (pulse frequency is 160Hz) and the corresponding fast Fourier analysis (FFT) analysis results. Figure 4 , Figure 6 , Figure 8 and Fig.10 The three different line types represent the three-phase voltages. Pulse loads will produce harmonic components related to the pulse frequency, and the main harmonic frequency is n(f pu ±f1), where n is a positive integer, f pu is the pulse frequency, f1 is the fundamental frequency. Figure 8 and Fig. 9 It can be seen that the 160Hz pulse load generates interharmonics with a frequency that is not an integer multiple of the fundamental frequency in the isolated island microgrid, and its THD is 8.81%. After implementing the harmonic suppression method of the present invention, the interharmonics caused by the 160Hz pulse load are effectively suppressed, and its THD is reduced to 1.77%. It can be concluded from the above two groups of working conditions that the harmonic suppression method provided by the present invention can suppress harmonic components including integer harmonics and interharmonics, achieve broadband voltage harmonic suppression, and effectively ensure the stable operation of the isolated island microgrid.

[0137] Please refer to Fig.12 , Fig.12A schematic diagram of the structure of a harmonic suppression device provided by the present invention; To solve the above technical problems, the present invention also provides a harmonic suppression device, comprising:

[0138] The harmonic determination unit 11 is used to perform phase-by-phase subtraction between the current PCC voltage of the isolated island microgrid and the ideal target voltage to obtain the harmonic voltage;

[0139] A feedforward compensation amount determination unit 12, used to determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in an island microgrid based on the harmonic voltage;

[0140] A compensation unit 13, configured to perform feedforward compensation on the current three-phase voltage modulation wave by using a feedforward compensation amount to obtain a target three-phase voltage modulation wave;

[0141] The control unit 14 is used to control the power switch tubes in the virtual synchronous generator using the target three-phase voltage modulation wave.

[0142] As an optional embodiment, it also includes:

[0143] A first parameter acquisition unit, used to acquire the current rated output voltage of the virtual synchronous generator and the phase angle of the current three-phase voltage modulation wave;

[0144] an ideal target voltage calculation unit, configured to calculate an ideal target voltage of the virtual synchronous generator based on the current rated output voltage and the phase angle of the current three-phase voltage modulation wave;

[0145] As an optional embodiment, the first parameter acquisition unit includes:

[0146] A second parameter acquisition unit is used to acquire an active power reference value of the virtual synchronous generator, a rated angular frequency of the output voltage, an active damping coefficient, a virtual moment of inertia, and a current instantaneous active power;

[0147] a phase angle calculation unit, configured to calculate the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator based on the active power reference value, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power;

[0148] As an optional embodiment, the feedforward compensation amount determination unit 12 includes:

[0149] A differential compensation unit, used to determine the product of the harmonic voltage and a preset feedforward coefficient;

[0150] The first feedforward compensation amount determination subunit is used to determine the feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator based on the product.

[0151] As an optional embodiment, the first feedforward compensation amount determination subunit includes:

[0152] A filtering compensation unit, used for controlling the product to be input to a first-order low-pass filter;

[0153] The second feedforward compensation amount determination subunit is used to determine the feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator based on the output signal of the first-order low-pass filter.

[0154] As an optional embodiment, the second feedforward compensation amount determination subunit includes:

[0155] A delay compensation unit, used for performing delay compensation on the output signal of the first-order low-pass filter;

[0156] The third feedforward compensation amount determination subunit uses the delay-compensated output signal as a feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator.

[0157] As an optional embodiment, the feedforward compensation amount determination unit 12 includes:

[0158] The compensation controller unit is used to input the harmonic voltage into a feedforward compensation controller to obtain a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator.

[0159] For an introduction to a harmonic suppression device provided by the present invention, please refer to the above-mentioned embodiment of the harmonic suppression method, and the present invention will not be described in detail here.

[0160] Please refer to Fig.13 , Fig.13 The present invention provides a schematic diagram of the structure of an electronic device. To solve the above technical problems, the present invention also provides an electronic device, including:

[0161] A memory 21, used for storing computer programs;

[0162] The processor 22 is used to implement the steps of the harmonic suppression method as described above.

[0163] Among them, the processor 22 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 22 can be implemented in at least one hardware form of DSP (Digital Signal Processor), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor 22 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a central processing unit; the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 22 may integrate a GPU (graphics processing unit), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 22 may also include an AI (Artificial Intelligence) processor, which is used to process computing operations related to machine learning.

[0164] The memory 21 may include one or more computer-readable storage media, which may be non-transitory. The memory 21 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory 21 is at least used to store the following computer program, wherein, after the computer program is loaded and executed by the processor 22, the relevant steps of the harmonic suppression method disclosed in any of the aforementioned embodiments can be implemented. In addition, the resources stored in the memory 21 may also include an operating system and data, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system may include Windows, Unix, Linux, etc. The data may include, but is not limited to, data of the harmonic suppression method, etc.

[0165] In some embodiments, the electronic device may further include a display screen, an input / output interface, a communication interface, a power supply, and a communication bus.

[0166] It can be understood by those skilled in the art that Fig.13 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or fewer components than shown in the figure.

[0167] For an introduction to an electronic device provided by the present invention, please refer to the above-mentioned embodiment of the harmonic suppression method, and the present invention will not be described in detail here.

[0168] In order to solve the above technical problems, 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 harmonic suppression method as described above are implemented.

[0169] It is understandable that if the method in the above embodiment is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium to execute all or part of the steps of the method described in each embodiment of the present application. Specifically, the computer-readable storage medium may include but is not limited to any type of disk, including a floppy disk, an optical disk, and a mobile hard disk, or any type of medium or device suitable for storing instructions, data, etc., and the present application does not make any special restrictions here.

[0170] For an introduction to a computer-readable storage medium provided by the present invention, please refer to the above-mentioned embodiment of the harmonic suppression method, and the present invention will not be repeated here.

[0171] 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.

[0172] It should also be noted that, in this specification, 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 "comprise", "include" 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, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0173] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0174] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A harmonic suppression method, characterized in that: include: The current PCC voltage of the island microgrid is subtracted from the ideal target voltage phase by phase to obtain the harmonic voltage; Determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in the island microgrid based on the harmonic voltage; Performing feedforward compensation on the current three-phase voltage modulation wave by using the feedforward compensation amount to obtain a target three-phase voltage modulation wave; The target three-phase voltage modulation wave is used to control the power switch tube in the virtual synchronous generator.

2. The harmonic suppression method according to claim 1, characterized in that: Also includes: Obtaining the current rated output voltage of the virtual synchronous generator and the phase angle of the current three-phase voltage modulation wave; Calculating the ideal target voltage of the virtual synchronous generator based on the current rated output voltage and the phase angle of the current three-phase voltage modulation wave; The calculation formula of the ideal target voltage is: ； in, is the rated output voltage of the virtual synchronous generator, is the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator.

3. The harmonic suppression method according to claim 2, characterized in that: Get the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator, including: Obtaining the active power reference value of the virtual synchronous generator, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power; Calculating the phase angle of the current three-phase voltage modulation wave of the virtual synchronous generator based on the active power reference value, the rated angular frequency of the output voltage, the active damping coefficient, the virtual moment of inertia and the current instantaneous active power; The calculation formula of the phase angle of the current three-phase voltage modulation wave is: ； in, is the active power reference value of the virtual synchronous generator, is the instantaneous active power of the virtual synchronous generator, is the rated angular frequency of the output voltage of the virtual synchronous generator, is the active damping coefficient of the virtual synchronous generator, ,and is the virtual moment of inertia of the virtual synchronous generator.

4. The harmonic suppression method according to any one of claims 1 to 3, characterized in that: Determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the harmonic voltage includes: Determining the product of the harmonic voltage and a preset feedforward coefficient; A feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator is determined based on the product.

5. The harmonic suppression method according to claim 4, characterized in that: Determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the product includes: Controlling the product to be input into a first-order low-pass filter; A feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator is determined based on an output signal of the first-order low-pass filter.

6. The harmonic suppression method according to claim 5, characterized in that: Determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on an output signal of the first-order low-pass filter comprises: Performing delay compensation on the output signal of the first-order low-pass filter; The output signal after delay compensation is used as a feedforward compensation amount for the current three-phase voltage modulation wave of the virtual synchronous generator.

7. The harmonic suppression method according to claim 5, characterized in that: Determining a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator based on the harmonic voltage includes: Inputting the harmonic voltage into a feedforward compensation controller to obtain a feedforward compensation amount for a current three-phase voltage modulation wave of the virtual synchronous generator; The transfer function of the feedforward compensation controller is: ； in, is the transfer function of the feedforward compensation controller, is the differential operator, is the preset feedforward coefficient, is the cut-off frequency of the first-order low-pass filter.

8. A harmonic suppression device, characterized in that: include: A harmonic determination unit is used to perform phase-by-phase subtraction between the current PCC voltage of the island microgrid and the ideal target voltage to obtain a harmonic voltage; A feedforward compensation amount determination unit, configured to determine a feedforward compensation amount for a current three-phase voltage modulation wave of a virtual synchronous generator in the island microgrid based on the harmonic voltage; A compensation unit, configured to perform feedforward compensation on the current three-phase voltage modulation wave by using the feedforward compensation amount to obtain a target three-phase voltage modulation wave; A control unit is used to control the power switch tube in the virtual synchronous generator using the target three-phase voltage modulation wave.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the harmonic suppression method according to any one of claims 1 to 7.

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 harmonic suppression method according to any one of claims 1 to 7 are implemented.

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