Frequency fluctuation suppression method and device of synchronous inverter and storage medium

Abstract

The invention discloses a frequency fluctuation suppression method and device for a synchronous inverter and a storage medium, and belongs to the technical field of converter control, and the method comprises the steps: calculating a virtual electromagnetic torque and virtual excitation based on the three-phase voltage and three-phase current of a virtual synchronous inverter; calculating and generating a new damping item according to the angular frequency rated value and the virtual angular frequency of the virtual synchronous inverter; substituting the virtual electromagnetic torque, the virtual excitation and the new damping term into a core equation of the virtual synchronous machine to obtain an updated virtual angular frequency, and calculating to obtain an active power given value through an active power-angular frequency mapping function; and feeding back the active power given value to a virtual mechanical torque input end of the virtual synchronous machine core equation to form closed-loop control so as to suppress frequency fluctuation of the system. According to the invention, the output of the active power given value is predicted by detecting the angular frequency of the module, so that the frequency fluctuation is suppressed, and the problem caused by the uncertainty of the load power change can be effectively improved.

Description

TECHNICAL FIELD

[0001] The application relates to a frequency fluctuation suppression method and device of a synchronous inverter and a storage medium, and belongs to the technical field of inverter control. BACKGROUND

[0002] The application aims to solve the problems of frequency fluctuation out of limits and poor power quality caused by the uncertainty of load power change in island mode of a distributed power supply, and provides an improved synchronous inverter control strategy, introduces a synchronous inverter frequency fluctuation suppression strategy of a shift method, and gives a function of an active power given value and a system angular frequency, so that the performance of the synchronous inverter in the frequency support performance is improved. The method can effectively improve the problems caused by the uncertainty of load power change.

[0003] The application relates to a frequency suppression method based on a virtual synchronous machine algorithm, which comprises the following steps: detecting system output voltage and current, calculating system active power and reactive power, collecting an angular frequency signal and constructing a function of active power given value and angular frequency change, outputting the given value of active power through angular frequency change, so as to accelerate the stability of frequency and meet the needs of a microgrid. A modulation wave signal is output by a virtual synchronous machine control module to realize sinusoidal pulse width modulation. SUMMARY

[0004] The application aims to overcome the defects in the prior art, and provides a frequency fluctuation suppression method and device of a synchronous inverter and a storage medium, which can predict the output of an active power given value through an angular frequency of a detection module, suppress frequency fluctuation, and effectively improve the problems caused by the uncertainty of load power change.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0006] In a first aspect, the application provides a frequency fluctuation suppression method of a synchronous inverter, which comprises the following steps:

[0007] Based on the pre-acquired three-phase voltage and three-phase current of the virtual synchronous inverter, the output active power and reactive power of the virtual synchronous inverter are calculated;

[0008] Based on the output active power and reactive power, the virtual electromagnetic torque and virtual excitation of the virtual synchronous inverter are calculated;

[0009] The angular frequency difference value is obtained by subtracting the virtual angular frequency of the virtual synchronous inverter from the pre-acquired angular frequency rated value;

[0010] According to the angular frequency difference value, the new damping term is calculated and generated in combination with the frequency droop coefficient and the integral coefficient;

[0011] The virtual electromagnetic torque, the virtual excitation, and a new damping term are substituted into the core equation of the virtual synchronous machine to obtain an updated virtual angular frequency;

[0012] Based on the updated virtual angular frequency, an active power given value is calculated through a preset active power-angular frequency mapping function;

[0013] The active power given value is fed back to the virtual mechanical torque input end of the virtual synchronous machine core equation to form a closed-loop control, thereby suppressing the frequency fluctuation of the system.

[0014] Further, the calculation of the output active power and the output reactive power of the virtual synchronous inverter based on the pre-acquired three-phase voltage and three-phase current of the virtual synchronous inverter comprises:

[0015] The acquired three-phase voltage and three-phase current are transformed through coordinate transformation to obtain d-axis voltage v d and d-axis current i d , and q-axis voltage v q and q-axis current i q .

[0016] Based on the v d , v q , i d , and i q , the output active power P and the output reactive power Q of the virtual synchronous inverter are calculated, and the calculation formula is:

[0017] ;

[0018] Wherein, E is the AC output terminal voltage amplitude of the bridge arm midpoint, δ is the phase, R and X are the resistance and reactance components of the line and load impedance, respectively.

[0019] Further, the calculation method of the virtual electromagnetic torque comprises:

[0020] Based on the electromagnetic transient relationship of the synchronous motor, the output active power P and the virtual angular frequency ω are used to calculate the virtual electromagnetic torque T e , and the numerical relationship is T e =P / ω.

[0021] Further, the calculation method of the virtual excitation comprises:

[0022] Based on the reactive power reference value Q ref and the output reactive power Q, the virtual excitation M f i f is calculated through a reactive power regulator, and the calculation formula is: , wherein K is the reactive power regulation coefficient.

[0023] Furthermore, based on the angular frequency difference, combined with the frequency droop coefficient and integral coefficient, a new damping term is calculated and generated, using the following formula:

[0024] ;

[0025] in, For the new damping term, D p This is the frequency droop coefficient. ω is the integral coefficient. n ω is the nominal angular frequency, and ω is the virtual angular frequency.

[0026] Furthermore, by substituting the virtual electromagnetic torque, virtual excitation, and the new damping term into the core equation of the virtual synchronous machine, the updated virtual angular frequency is obtained. The calculation formula is as follows:

[0027] ;

[0028] Where J is the virtual inertia, For the updated virtual angular frequency, T m It is virtual mechanical torque. Indicates the current time The instantaneous change in time, It is the instantaneous change in virtual rotational speed.

[0029] Furthermore, based on the updated virtual angular frequency, the active power setpoint is calculated using a preset active power-angular frequency mapping function, as shown in the following formula:

[0030] ;

[0031] Where, ω e ω is the set value for angular frequency. emax The maximum value of the angular frequency setting, ω emin The minimum value of the angular frequency setting. P represents the change in maximum output power. ref P is the initial setpoint for active power. set The given value for the calculated active power.

[0032] Secondly, the present invention provides a frequency fluctuation suppression device for a synchronous inverter, used to implement the frequency fluctuation suppression method for a synchronous inverter as described in any one of the preceding claims, characterized in that it includes:

[0033] The first calculation module is used to calculate the output active power and reactive power of the virtual synchronous inverter based on the pre-collected three-phase voltage and three-phase current of the virtual synchronous inverter.

[0034] The second calculation module is used to calculate the virtual electromagnetic torque and virtual excitation based on the output active power and output reactive power.

[0035] The first processing module is used to subtract the pre-acquired angular frequency rated value from the virtual angular frequency of the virtual synchronous inverter to obtain the angular frequency difference value.

[0036] The third calculation module is used to calculate and generate a new damping term based on the angular frequency difference, combined with the frequency droop coefficient and the integral coefficient.

[0037] The second processing module is used to substitute the virtual electromagnetic torque, virtual excitation and the new damping term into the core equation of the virtual synchronous machine to solve for the updated virtual angular frequency.

[0038] The fourth calculation module is used to calculate the active power setpoint based on the updated virtual angular frequency and through a preset active power-angular frequency mapping function.

[0039] The fluctuation suppression module is used to feed back the active power setpoint to the virtual mechanical torque input terminal of the core equation of the virtual synchronizer to form a closed-loop control, thereby suppressing the frequency fluctuation of the system.

[0040] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0041] Fourthly, the present invention provides an electronic device, comprising:

[0042] Memory, used to store computer programs / instructions;

[0043] A processor for executing the computer program / instructions to implement the steps of any of the methods described above.

[0044] Fifthly, the present invention provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of any of the methods described above.

[0045] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0046] This invention provides a method, apparatus, and storage medium for suppressing frequency fluctuations in synchronous inverters. Based on the concept of a virtual synchronous machine control, it suppresses frequency fluctuations by predicting the output of the active power setpoint through the detection module's angular frequency. Applying the novel algorithm of this invention can effectively improve the problems caused by the uncertainty of load power changes. Attached Figure Description

[0047] Figure 1A three-phase PWM inverter three-level circuit topology provided by an embodiment of the present application.

[0048] Figure 2 A micro-grid frequency fluctuation suppression process diagram under load change provided by an embodiment of the present application.

[0049] Figure 3 A control block diagram of synchronous inverter frequency fluctuation suppression provided by an embodiment of the present application.

[0050] Figure 4 A control block diagram of synchronous inverter frequency fluctuation suppression with introduction of translation method provided by an embodiment of the present application.

[0051] Figure 5 A simulation diagram of frequency of synchronous inverter frequency fluctuation suppression and synchronous inverter frequency fluctuation suppression with introduction of translation method provided by an embodiment of the present application.

[0052] Figure 6 An experimental waveform diagram of frequency of synchronous inverter frequency fluctuation suppression and synchronous inverter frequency fluctuation suppression with introduction of translation method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0053] The present application will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0054] Embodiment 1, the present embodiment introduces a frequency fluctuation suppression method of a synchronous inverter, comprising:

[0055] Based on the pre-acquired three-phase voltage and three-phase current of the virtual synchronous inverter, the output active power and reactive power of the virtual synchronous inverter are calculated;

[0056] Based on the output active power and reactive power, the virtual electromagnetic torque and virtual excitation are calculated;

[0057] The pre-acquired angular frequency rated value is subtracted from the virtual angular frequency of the virtual synchronous inverter to obtain an angular frequency difference value;

[0058] According to the angular frequency difference value, a new damping term is calculated and generated in combination with a frequency droop coefficient and an integral coefficient;

[0059] The virtual electromagnetic torque, virtual excitation and new damping term are substituted into the core equation of the virtual synchronous machine to obtain an updated virtual angular frequency;

[0060] Based on the updated virtual angular frequency, an active power given value is calculated through a pre-set active power-angular frequency mapping function;

[0061] The active power setpoint is fed back to the virtual mechanical torque input terminal of the core equation of the virtual synchronous machine to form closed-loop control, thereby suppressing the frequency fluctuation of the system.

[0062] The frequency fluctuation suppression method for synchronous inverters provided in this embodiment Figure 1 This is a three-level circuit topology diagram of a three-phase PWM inverter provided in an embodiment of the present invention. A three-level topology with diode clamping is adopted, Q1-Q... 12 It consists of 12 insulated-gate bipolar transistors (IGBTs) with anti-parallel diodes; D1-D6 are 6 clamping diodes. L c R c These are the converter-side filter inductor and its internal resistance, respectively; L g R g These are the grid-side filter inductor and its internal resistance, respectively; C f For AC side filter capacitor; R d This is a damping resistor. ga v gb v gc These are the phase voltages of the three-phase power grid, sampled using voltage sensors; i ga i gb i gc These are the three-phase grid-connected currents, sampled using current sensors; e a e b e c These are the fundamental frequencies of the output voltage at the midpoint of the three-phase bridge arm, respectively; v ao v bo v co These are the AC voltages of the three-phase filter capacitors; i L This is the output current of the DC voltage source; v dc The voltage is the DC voltage source voltage or the energy storage battery voltage, and the value is sampled using a voltage sensor; C1 and C2 are the upper and lower split capacitors on the DC side, respectively.

[0063] like Figure 2 The diagram illustrates the frequency fluctuation suppression process of a microgrid under load variations, including a phase-locked loop (PLL), a synchronous machine core component, a frequency fluctuation suppression component, a direct power loop, a reactive power loop, a process quantity calculation loop, and a PWM modulation loop. The frequency fluctuation suppression component calculates the difference between the rated angular frequency and the virtual angular frequency, and then multiplies this difference by a frequency droop coefficient D. p The difference between the angular frequency and the integrator is summed to form the new damping component, where S1 is the switch that switches the synchronous inverter to the frequency fluctuation suppression state, and K... i The integral coefficients of the integrator are then added to the rocking equation, thus the frequency droop coefficient D...p and integral coefficient K i It can be analogized to PI controller to realize zero static error control of angular frequency. The new damping part is:

[0064] ;

[0065] wherein, is the new damping term, D p is the frequency droop coefficient, is the integral coefficient, ω n is the rated value of angular frequency, and ω is the virtual angular frequency;

[0066] The core of synchronous machine refers to the mechanical motion equation of synchronous motor. The virtual inertia J, the virtual angular frequency , the virtual electromagnetic torque T e , the virtual mechanical torque T m , and the virtual damping D p are introduced in the control of three-phase PWM rectifier. The specific expressions are as follows:

[0067] ;

[0068] wherein, J is the virtual inertia, is the updated virtual angular frequency, T m is the virtual mechanical torque, represents the time instantaneous change amount at the current time , and is the virtual speed instantaneous change amount;

[0069] The integral calculation of is carried out to obtain the rectifier phase angle θ, as shown in the following formula:

[0070] ;

[0071] The actual angular frequency ω g of power grid is obtained by PLL phase-locked loop.

[0072] The excitation equation of synchronous motor is referred to in the control of three-phase PWM rectifier. The virtual excitation M f i f and the reactive power regulation coefficient K are introduced. Q ref is the reactive power reference value. Q is the actual instantaneous reactive power. The virtual excitation M f i f is calculated by the following formula:

[0073] ;

[0074] The process amount calculation link calculates the virtual electromagnetic torque T einstantaneous reactive power Q and virtual counter electromotive force .

[0075] virtual electromagnetic torque T e The virtual electromagnetic torque T is calculated from the electromagnetic transient relationship of the synchronous machine by the following equation:

[0076] ;

[0077] wherein ; ; denotes the vector transposition.

[0078] The instantaneous reactive power Q is calculated by the following equation:

[0079] ;

[0080] virtual counter electromotive force is obtained by the following equation.

[0081] ;

[0082] wherein .

[0083] The virtual counter electromotive force is sent into the PWM modulation loop and intersects with the triangular carrier wave in the SPWM modulation mode to obtain high-frequency PWM pulses to control the switching tube, and finally realize the virtual synchronous control of the energy storage converter. Figure 1

[0084] Figure 3 is the frequency fluctuation suppression process of the microgrid. When the load suddenly increases, the angular frequency will decrease from the rated angular frequency ω n to ω1, and change from the original stable point A to point B. At this time, if the given value of active power is changed, it means that the curve of active power and angular frequency will be shifted to the right. Then, under this given active power, the B point will be shifted to the right to point C, and the angular frequency ω2 corresponding to point C is closer to the rated angular frequency ω n than the distance between ω1 and the rated angular frequency ω n . When the load suddenly decreases, the angular frequency will increase from the rated angular frequency ω n to ω1, and change from the original stable point A to point B. At this time, if the given value of active power is changed, it means that the curve of active power and angular frequency will be shifted to the left. Then, under this given active power, the B point will be shifted to the right to point C, and the angular frequency ω2 corresponding to point C is closer to the rated angular frequency ω n than the distance between ω1 and the rated angular frequency ω n .

[0085] As​​Figure 4 As shown in the figure, the synchronous inverter frequency fluctuation suppression control block diagram of the translation method is introduced, and the active power given value is constructed as a function of the angular frequency according to the above two cases, combined with the range of inverter output power and the range of angular frequency in the microgrid. The angular frequency setting value The maximum value is limited by the maximum output power P max of the inverter. The maximum value is determined by the system angular frequency, the rated angular frequency, the frequency droop coefficient and the maximum active power difference at this moment, which means that the active power given value and the angular frequency curve are translated in the direction of increasing ΔP max , until the most suitable curve is selected. When the angular frequency of the system runs to the minimum value, the inverter should output the maximum power at this time, and ΔP max corresponds to The maximum angular frequency setting value selected by the system, so that the interval of can be determined. The function of the active power given value with the angular frequency is as follows:

[0086] ;

[0087] Where ω e is the angular frequency setting value, ω emax is the maximum value of the angular frequency setting value, ω emin is the minimum value of the angular frequency setting value, is the change amount of the maximum output power, P ref is the initial given value of the active power, P set is the calculated active power given value.

[0088] The output of the active power given value is predicted by the angular frequency, so that the frequency fluctuation range is smaller.

[0089] As shown in Figure 5 , the energy storage converter uses the control method of the application for simulation, the DC voltage source voltage given value is 750V, the active power reference value is 0kW, the reactive power reference value is 0kVar, the rated voltage effective value is 220V, and the rated angular frequency is equal to 314rad / s. The system is operated at no load from 0 to 1s, a three-phase resistance load is suddenly added at t=1s, and a three-phase resistance load is suddenly reduced at t=2.5s.

[0090] As shown in Figure 5 (a), the simulation results of primary frequency regulation can be seen, when loading at t=1s, the frequency drop difference is 0.101Hz, and when unloading at t=2.5s, the frequency rises to 50Hz. From Figure 5(b) The simulation results of the frequency fluctuation suppression shown can be seen that at t = 1s, the load is loaded, the frequency difference is reduced by 0.082Hz, and after about 0.5s, the frequency is restored to 50Hz, at t = 2.5s, the load is unloaded, the frequency is increased by 0.082Hz from the stable 50Hz, and then after about 0.5s, the frequency is restored to 50Hz. From Figure 5 (c) The simulation results of the frequency fluctuation suppression shown can be seen that at t = 1s, the load is loaded, the frequency difference is reduced by 0.076Hz, and after about 0.5s, the frequency is restored to 50Hz, at t = 2.5s, the load is unloaded, the frequency is increased by 0.076Hz from the stable 50Hz, and then after about 0.5s, the frequency is restored to 50Hz. Secondly, from the A-phase output voltage waveform graph of the three graphs, it can be seen that at the loading moment, the voltage amplitude also appears different degrees of reduction. Finally, the frequency drop comparison can be seen that the frequency fluctuation suppression algorithm with the introduction of the translation method can reduce the frequency change range caused by the load disturbance, and better meet the stable operation of the microgrid system.

[0091] As Figure 6 shown, the energy storage converter adopts the control method of the application to experimentally verify the primary frequency regulation, frequency fluctuation suppression and frequency fluctuation suppression control algorithm with the introduction of the translation method at the power level of 10kW. The system is initially operated in the no-load state, a 10kW resistance load is suddenly added at a certain moment, and the change of the key parameter frequency under the three control strategies is compared and observed.

[0092] Figure 6 (a) is the experimental waveform when the frequency f is suddenly loaded with 10kW load when the active power initial given value is 0kW and the reactive power given value is 0kVar. It can be seen that the frequency is reduced by about 0.107Hz at the loading moment, and then the frequency is always stable. The frequency change amplitude is about 10.7%, which meets the damping parameter design principle, and the frequency transition time is about 80ms.

[0093] Figure 6 (b) is the experimental waveform when the frequency f is suddenly loaded with 10kW load when the active power initial given value is 0kW and the reactive power given value is 0kVar. It can be seen that the frequency is reduced by about 0.085Hz at the loading moment, and the frequency is restored to 50Hz after 720ms. The frequency change amplitude is about 8.5%.

[0094] Figure 6(c) The experimental waveform when a 10kW load is suddenly added to the frequency fluctuation suppression algorithm with the initial given value of active power being 0kW and the given value of reactive power being 0kVar. It can be seen that the frequency drops by about 0.048Hz when the load is added, and the frequency returns to 50Hz after 800ms. The frequency change amplitude is about 4.8%.

[0095] The frequency fluctuation suppression can achieve frequency error-free control relative to primary frequency modulation, and the frequency fluctuation suppression with the shift method can achieve a smaller frequency change range under the same load mutation compared with the pure frequency fluctuation suppression control algorithm. Under a 10kW load mutation, the change range interval is reduced by 43.53%, and the frequency overrun is less likely to occur. The reason why the control algorithm is effective is that the mutation of the load will cause the given value of active power to change, and then cause the frequency to move.

[0096] The embodiment provides a frequency fluctuation suppression method of a synchronous inverter, which is based on the virtual synchronous machine control idea, and the output of the given value of active power is predicted by detecting the angular frequency of a module to suppress frequency fluctuation. The new algorithm of the application can effectively improve the problems caused by the uncertainty of load power change.

[0097] Embodiment 2 provides a frequency fluctuation suppression method of a synchronous inverter, and the method is characterized in that the method comprises the following steps:

[0098] The first calculation module is configured to calculate the output active power and the output reactive power of the virtual synchronous inverter based on the pre-acquired three-phase voltage and three-phase current of the virtual synchronous inverter.

[0099] The second calculation module is configured to calculate the virtual electromagnetic torque and the virtual excitation based on the output active power and the output reactive power.

[0100] The first processing module is configured to obtain an angular frequency difference value by subtracting the virtual angular frequency of the virtual synchronous inverter from the pre-acquired angular frequency rated value.

[0101] The third calculation module is configured to calculate a new damping term according to the angular frequency difference value in combination with a frequency droop coefficient and an integral coefficient.

[0102] The second processing module is configured to substitute the virtual electromagnetic torque, the virtual excitation and the new damping term into the core equation of the virtual synchronous machine to obtain an updated virtual angular frequency.

[0103] The fourth calculation module is configured to calculate the given value of active power based on the updated virtual angular frequency through a pre-set active power-angular frequency mapping function.

[0104] A fluctuation suppression module is configured to feed back the active power given value to a virtual mechanical torque input of the virtual synchronous machine core equation to form a closed loop control, so as to suppress frequency fluctuation of the system.

[0105] The specific function implementation of each module is described in the related content in the method of the embodiment 1, and is not described herein.

[0106] Embodiment 3 provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the steps of the method in any one of the embodiments 1.

[0107] Embodiment 4 provides an electronic device, which comprises:

[0108] A memory is configured to store a computer program / instruction;

[0109] A processor is configured to execute the computer program / instruction to implement the steps of the method in any one of the embodiments 1.

[0110] Embodiment 5 provides a computer program product, which comprises a computer program / instruction, and the computer program / instruction is executed by a processor to implement the steps of the method in any one of the embodiments 1.

[0111] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, without departing from the technical principles of the present application, several improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

[0112] Those skilled in the art will appreciate that embodiments of the present disclosure can be provided as methods, systems or computer program products. Therefore, the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0113] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each flow and / or block in the flowcharts and / or block diagrams and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the computer or other programmable data processing device produce a device that implements the functions described in the flowcharts and / or block diagrams. Figure 1apparatuses that implement the functions specified in the flowchart(s) or flowchart block(s). Figure 1

[0114] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flowchart(s) or flowchart block(s). Figure 1 Figure 1

[0115] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the flowchart(s) or flowchart block(s). Figure 1 Figure 1

[0116] Finally, it should be noted that the above-described embodiments are merely used to illustrate the technical solutions of the present disclosure, rather than limit the scope of protection of the present disclosure. Although the present disclosure has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that, after reading the present disclosure, those skilled in the art can make various modifications, changes or equivalent replacements to the specific embodiments. However, these modifications, changes or equivalent replacements should still fall within the scope of the protection of the disclosure.​​​​​

Claims

1. A method for suppressing frequency fluctuations in a synchronous inverter, characterized in that, include: Based on the pre-collected three-phase voltage and three-phase current of the virtual synchronous inverter, calculate the output active power and reactive power of the virtual synchronous inverter; Based on the output active power and output reactive power, calculate the virtual electromagnetic torque and virtual excitation; The difference between the pre-obtained rated angular frequency and the virtual angular frequency of the virtual synchronous inverter is obtained. Based on the angular frequency difference, combined with the frequency droop coefficient and integral coefficient, a new damping term is calculated and generated; Substituting the virtual electromagnetic torque, virtual excitation, and the new damping term into the core equation of the virtual synchronous machine, the updated virtual angular frequency is obtained by solving the equation. Based on the updated virtual angular frequency, the active power setpoint is calculated using a preset active power-angular frequency mapping function; The active power setpoint is fed back to the virtual mechanical torque input terminal of the core equation of the virtual synchronous machine to form closed-loop control, thereby suppressing the frequency fluctuation of the system.

2. The frequency fluctuation suppression method for a synchronous inverter according to claim 1, characterized in that, The calculation of the output active and reactive power of the virtual synchronous inverter based on the pre-acquired three-phase voltage and three-phase current of the virtual synchronous inverter includes: The collected three-phase voltages and three-phase currents are transformed using coordinates to obtain the d-axis voltage v. d and d-axis current i d and q-axis voltage v q and q-axis current i q ; Based on the v d v q i d and i q Calculate the output active power P and output reactive power Q of the virtual synchronous inverter using the following formula: ； Where E is the AC output voltage amplitude at the midpoint of the bridge arm, δ is the phase, and R and X are the resistance and reactance components of the line and load impedances, respectively.

3. The frequency fluctuation suppression method for a synchronous inverter according to claim 2, characterized in that, The method for calculating the virtual electromagnetic torque includes: Based on the electromagnetic transient relationship of the synchronous motor, the virtual electromagnetic torque T is calculated using the output active power P and the virtual angular frequency ω. e The numerical relationship is: T e =P / ω.

4. The frequency fluctuation suppression method for a synchronous inverter according to claim 3, characterized in that, The method for calculating the virtual excitation includes: Based on the reactive power reference value Q ref The output reactive power Q is used to calculate the virtual excitation M through the reactive power regulator. f i f The calculation formula is as follows: , where K is the reactive power regulation coefficient.

5. The frequency fluctuation suppression method for a synchronous inverter according to claim 4, characterized in that, The new damping term is calculated based on the angular frequency difference, combined with the frequency droop coefficient and the integral coefficient. The calculation formula is as follows: ； in, For the new damping term, D p This is the frequency droop factor. ω is the integral coefficient. n ω is the nominal angular frequency, and ω is the virtual angular frequency.

6. The frequency fluctuation suppression method for a synchronous inverter according to claim 5, characterized in that, The virtual electromagnetic torque, virtual excitation, and new damping term are substituted into the core equation of the virtual synchronous machine to obtain the updated virtual angular frequency. The calculation formula is as follows: ； Where J is the virtual inertia, For the updated virtual angular frequency, T m It is virtual mechanical torque. Indicates the current time The instantaneous change in time, It is the instantaneous change in virtual rotational speed.

7. The frequency fluctuation suppression method for a synchronous inverter according to claim 6, characterized in that, Based on the updated virtual angular frequency, the active power setpoint is calculated using a preset active power-angular frequency mapping function, as shown in the following formula: ； Where, ω e ω is the set value for angular frequency. emax The maximum value of the angular frequency setting, ω emin The minimum value of the angular frequency setting. P represents the change in maximum output power. ref P is the initial setpoint for active power. set The given value for the calculated active power.

8. A frequency fluctuation suppression device for a synchronous inverter, used to implement the frequency fluctuation suppression method for a synchronous inverter according to any one of claims 1-7, characterized in that, include: The first calculation module is used to calculate the output active power and reactive power of the virtual synchronous inverter based on the pre-collected three-phase voltage and three-phase current of the virtual synchronous inverter. The second calculation module is used to calculate the virtual electromagnetic torque and virtual excitation based on the output active power and output reactive power. The first processing module is used to subtract the pre-acquired angular frequency rated value from the virtual angular frequency of the virtual synchronous inverter to obtain the angular frequency difference value. The third calculation module is used to calculate and generate a new damping term based on the angular frequency difference, combined with the frequency droop coefficient and the integral coefficient. The second processing module is used to substitute the virtual electromagnetic torque, virtual excitation and the new damping term into the core equation of the virtual synchronous machine to solve for the updated virtual angular frequency. The fourth calculation module is used to calculate the active power setpoint based on the updated virtual angular frequency and through a preset active power-angular frequency mapping function. The fluctuation suppression module is used to feed back the active power setpoint to the virtual mechanical torque input terminal of the core equation of the virtual synchronizer to form a closed-loop control, thereby suppressing the frequency fluctuation of the system.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When executed by a processor, the computer program implements the steps of the method described in any one of claims 1-7.

10. An electronic device, characterized in that, include: Memory, used to store computer programs / instructions; A processor for executing the computer program / instructions to implement the steps of the method according to any one of claims 1-7.

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