A method and system for suppressing power oscillations in parallel multi-grid converter systems

Abstract

This invention discloses a power oscillation suppression method and system for parallel multi-grid converter systems, relating to the field of converter control technology. The method includes: acquiring the voltage, current, and voltage frequency output by the three-phase converters at the grid connection point in the parallel multi-grid converter system; calculating the active power and reactive power and inputting them into a virtual oscillator; obtaining system power reference compensation based on the voltage frequency and rated frequency via an introduced proportional-differential controller; then combining the active power and active power reference values, and passing them through the active power droop stage of the virtual oscillator to obtain the frequency deviation, thereby calculating the voltage phase angle; simultaneously, obtaining the voltage amplitude through the reactive power control stage of the virtual oscillator; calculating the system reference voltage based on the voltage amplitude and voltage phase angle; and adjusting the output of the three-phase converters in real time via voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillations.

Description

Technical Field

[0001] This invention relates to the field of converter control technology, and in particular to a method and system for suppressing power oscillations in parallel multi-grid converter systems. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the increasing proportion of installed capacity from renewable energy sources, primarily wind and solar power, the power system is exhibiting characteristics such as significantly reduced inertia and frequent occurrences of weak grid conditions, severely threatening system stability. Therefore, novel grid control technologies, such as droop control, virtual synchronous machine control, and Virtual Oscillator Control (VOC), have become research hotspots. Among these, VOC, as a time-domain control strategy, regulates frequency and voltage by simulating the dynamic characteristics of a weakly nonlinear oscillator, improving the system's dynamic performance and enabling synchronization between converters to be independent of inertia, achieving synchronization at any power angle. Therefore, VOC significantly outperforms droop control and virtual synchronous machine control in terms of self-synchronization and power sharing, making this control strategy highly sought after.

[0004] However, after new energy equipment based on VOC control is connected to the grid, because it lacks the mechanical inertia of a synchronous motor, the frequency and output active power of the parallel system are prone to transient power oscillations when encountering load fluctuations or inconsistent line impedances, which is detrimental to the stable operation of the system. Currently, power oscillation suppression strategies based on VOC are key to the parallel connection of multiple grid-connected converters, and they mainly focus on dynamic parameter optimization and increasing transient damping. Among them, the dynamic parameter optimization scheme adjusts parameters such as the oscillation amplitude and frequency response coefficient of VOC in real time to match the dynamic demand of the system. This method makes full use of the reconfigurable advantage of VOC parameters, but its control law often relies on empirically designed nonlinear functions and lacks the support of strict Lyapunov stability theory, making it difficult to achieve precise quantitative control of the power dynamic process. Transient damping suppresses power oscillations by introducing virtual damping terms, usually using a state observer to construct virtual damping. This method avoids direct differentiation calculations, but increases the order of the VOC model, affecting the dynamic characteristics of the system, and requires a balance between steady-state accuracy and transient robustness. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention provides a power oscillation suppression method and system for multi-grid converter parallel systems. By using frequency feedback and introducing a proportional-derivative controller and dynamically adjusting system parameters, the method achieves stable operation of multiple grid-connected converters in parallel. This method is simple, practical, and highly stable, and can effectively solve the power oscillation problem of grid-connected converters in parallel.

[0006] In a first aspect, the present invention provides a method for suppressing power oscillations in parallel systems of multi-grid converters.

[0007] A power oscillation suppression method for parallel multi-grid converter systems includes:

[0008] Collect the voltage, current and voltage frequency output of the three-phase converter at the grid connection point in a multi-grid converter parallel system;

[0009] Based on voltage and current, calculate the active and reactive power of the three-phase converter and input them into the virtual oscillator;

[0010] Based on the voltage frequency and rated frequency, the system power reference compensation is obtained through the introduced proportional-differential controller. Then, the active power and active power reference value are combined and the frequency deviation is obtained through the active droop element of the virtual oscillator, and then the voltage phase angle is calculated. At the same time, the reactive power is obtained through the reactive power control element of the virtual oscillator to obtain the voltage amplitude.

[0011] The system reference voltage is calculated based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, the output of the three-phase converter is adjusted in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

[0012] Secondly, the present invention provides a power oscillation suppression system for parallel systems of multi-grid converters.

[0013] A power oscillation suppression system for parallel multi-grid converter systems includes:

[0014] The signal acquisition module is used to acquire the voltage, current and voltage frequency output by the three-phase converter at the grid connection point in a multi-grid converter parallel system;

[0015] The calculation module is used to calculate the active and reactive power of the three-phase converter based on voltage and current and input it into the virtual oscillator;

[0016] The compensation module is used to obtain system power reference compensation based on the voltage frequency and rated frequency through the introduced proportional-differential controller. Then, it combines the active power and active power reference value, and obtains the frequency deviation through the active droop element of the virtual oscillator, and then calculates the voltage phase angle. At the same time, the reactive power is obtained through the reactive power control element of the virtual oscillator to obtain the voltage amplitude.

[0017] The adjustment module is used to calculate the system reference voltage based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, the output of the three-phase converter is adjusted in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

[0018] Thirdly, the present invention also provides an electronic device, comprising: a memory for storing executable instructions; and a processor for implementing the above-described power oscillation suppression method for a multi-grid converter parallel system when executing the executable instructions stored in the memory.

[0019] Fourthly, the present invention also provides a computer-readable storage medium storing executable instructions for causing a processor to execute the executable instructions to implement the above-described power oscillation suppression method for parallel systems of multi-grid converters.

[0020] Fifthly, the present invention also provides a computer program product comprising executable instructions stored in a computer-readable storage medium; wherein, when the processor of an electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, it implements the above-described power oscillation suppression method for parallel systems of multi-grid converters.

[0021] The above one or more technical solutions have the following beneficial effects:

[0022] 1. This invention provides a power oscillation suppression method and system for multi-grid converter parallel systems. In parallel converter systems with differences in line impedance, frequency feedback and the introduction of a proportional-derivative (PD) controller and dynamic adjustment of system parameters are used to achieve stable operation of multiple grid-connected converters in parallel. Specifically, the frequency feedback strategy involves the PD controller dynamically correcting the power reference value based on the feedback frequency, thereby introducing an advance damping effect in the early stages of power fluctuations. This significantly suppresses transient fluctuations in active power and improves the dynamic stability of the system. The PD control only operates during transient processes and automatically exits in steady state, suppressing oscillations while avoiding the introduction of steady-state errors, ensuring that the system quickly recovers to steady-state operation after dynamic disturbances.

[0023] 2. This invention can directly construct control compensation quantities through a frequency feedback strategy, without relying on empirically designed nonlinear functions or complex state observers, which can effectively simplify the controller parameter tuning process and improve engineering applicability.

[0024] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0026] Figure 1 This is a topology diagram of a parallel system of multiple converters with inconsistent line impedances in an embodiment of the present invention;

[0027] Figure 2 This is a power oscillation suppression control structure diagram of a grid-type three-phase converter parallel system based on a virtual oscillator in an embodiment of the present invention;

[0028] Figure 3 This is a comparison diagram of the active power waveforms of the improved strategy proposed in this embodiment of the invention and the original strategy. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are exemplary and are intended only to describe specific embodiments and to provide further explanation of the invention, and are not intended to limit the scope of exemplary embodiments of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Example 1

[0031] Facing Figure 1 The illustrated multi-converter parallel system with inconsistent line impedances provides a frequency feedback-based method for suppressing parallel power oscillations in grid-connected converters, comprising the following steps:

[0032] Step S1: Collect the voltage, current and voltage frequency output by the three-phase converter at the grid connection point in the multi-grid converter parallel system;

[0033] Step S2: Calculate the active and reactive power of the three-phase converter based on the voltage and current, and input them into the virtual oscillator.

[0034] Specifically, such as Figure 1 As shown, the three-phase grid-connected converter uses a voltage-source three-phase bridge inverter circuit as the main circuit, and a DC voltage source as the inverter input signal. The DC voltage source is converted into a three-phase AC voltage source through a three-phase six-arm bridge circuit, and then connected to the power grid via a three-phase filter circuit. Based on this, as... Figure 2As shown, for each three-phase grid-connected converter in a distributed power source (DG) branch, the voltage and current output of the three-phase converter (i.e., the voltage and current output at the grid connection point PCC) are collected, and the frequency of the output voltage at the grid connection point is collected as feedback.

[0035] Furthermore, based on the collected voltage and current, the active and reactive power of the three-phase converter are calculated. First, the collected voltage and current outputs of the three-phase converter are subjected to Clark and Park transformations. This transformation converts the three-phase voltage and current signals into a two-phase rotating coordinate system (i.e., abc / dq transformation), obtaining the two-phase voltage and current, which facilitates PI control. The transformation model is as follows:

[0036] , , (1)

[0037] In the above formula, and These represent the voltage and current output by the three-phase converter, respectively. This is the phase angle of the converter output voltage.

[0038] The voltage in the two-phase rotating coordinate system was calculated. and current Based on the two-phase voltage and current, calculate the active power and reactive power of the three-phase converter respectively. The calculation formula is as follows:

[0039] (2)

[0040] Subsequently, active and reactive power are introduced into the virtual oscillator, and the converter output is adjusted in real time through voltage and current feedback to achieve stable system operation. The virtual oscillator, as a nonlinear controller, has a dynamic mathematical model expressed in polar coordinates as follows:

[0041] (3)

[0042] (4)

[0043] In the above formula, , Given a voltage reference value; This is the natural resonant frequency, i.e., the rated frequency; This is the output voltage of the virtual oscillator; It is a resonant capacitor; The convergence coefficient; This is the voltage / current proportionality coefficient; and These are the active power reference and reactive power reference of the converter, respectively. The line impedance angle; , Represents the derivative of a two-phase voltage, indicated by the superscript. This represents the derivative value of the corresponding parameter; It represents the voltage difference between two phase voltages.

[0044] Typically, line impedance is equivalent to pure inductive impedance, i.e. Based on the voltage amplitude and phase angle expression (4), its dynamic mathematical model can be simplified as follows:

[0045] (5)

[0046] In the above formula, , It represents the derivative of voltage magnitude and phase angle; and These represent the active power and reactive power output of the converter, respectively. and It is calculated from the voltage and current of the three-phase converter.

[0047] Therefore, and After incorporating the VOC control model (5), converter network control based on a virtual oscillator can be achieved through voltage and current dual closed-loop regulation. Preferably, considering the rotating coordinate system in the inductive network... d Axis and q Since the shaft signal is coupled, it cannot be precisely controlled. Therefore, the signal is decoupled when a voltage and current dual closed loop is introduced.

[0048] However, considering that the active power output of the parallel system is prone to transient power oscillation during the grid connection process of new energy equipment based solely on VOC control, this embodiment improves the above VOC control method by applying it to a multi-converter parallel system. By acquiring the converter output frequency in real time as feedback, and introducing a proportional-derivative controller to dynamically adjust the system power reference and increase system damping, since the derivative element only acts on the dynamic process of the system, power oscillation can be suppressed without affecting the steady state of the system, thus achieving stable operation of multiple grid-connected new energy converters in parallel.

[0049] In other words, under weak grid conditions, the control objective of a three-phase grid-connected converter parallel system is to obtain stable output voltage and current, suppress transient fluctuations in active power and frequency, and achieve stable operation of the multi-converter parallel system. This control objective can be transformed into:

[0050] (6)

[0051] in," " " represents "to achieve tracking.

[0052] To meet the above control objectives, and considering that in a parallel converter system, due to differences in line impedance, load variations, and other factors, it is difficult for the controllers to maintain balance, leading to power oscillations that affect system stability and power quality, the suppression strategy adopted in this embodiment is as follows:

[0053] Step S3: Based on the voltage frequency and rated frequency, the system power reference compensation is obtained through the introduced proportional-differential controller. Then, the active power and active power reference value are combined and the frequency deviation is obtained through the active droop element of the virtual oscillator, and then the voltage phase angle is calculated. At the same time, the reactive power is obtained through the reactive power control element of the virtual oscillator to obtain the voltage amplitude.

[0054] Specifically, for distributed converters that generate active power oscillations, the above-mentioned method of acquiring output voltage is used. and current The active power is calculated, and the above describes the power calculation method in a two-phase rotating coordinate system. The formula for calculating active power in a three-phase coordinate system is as follows:

[0055] (7)

[0056] The mathematical model of the introduced proportional-derivative controller is as follows:

[0057] (8)

[0058] in, For the input error signal, For output signal, This is the proportionality coefficient. is the differential coefficient.

[0059] Considering that under purely inductive circuit conditions, active power and frequency have an approximate droop relationship, therefore, if Figure 2 As shown, after introducing a proportional-derivative (PD) controller, firstly, based on the acquired voltage frequency and rated frequency, the system power reference compensation value is obtained through the introduced PDC controller, which is:

[0060] (9)

[0061] In the above formula, This represents a differential controller, equivalent to the one in equation (8). , s This indicates that the input deviation signal is differentiated.

[0062] Due to the differential element and the rate of change of the deviation in the aforementioned PD controller The frequency is directly proportional to the reference value. Therefore, by introducing a proportional-derivative controller, the system damping can be increased, that is, the resistance in the dynamic adjustment process of the system can be increased. The faster the system frequency deviates from the reference value, the greater the reverse adjustment effect provided by the derivative element, thereby effectively suppressing oscillation.

[0063] Then, the active power The system power reference compensation value is input into the active power droop element of the virtual oscillator model to compensate for the system power reference compensation value. The active power reference value is used to dynamically adjust the system power reference, thereby calculating the final angular frequency deviation of the VOC. ,Right now:

[0064] (10)

[0065] in, This is the proportionality coefficient.

[0066] Next, the rated angular frequency Subtract angular frequency deviation Obtain the system angular frequency The phase angle of the output voltage is obtained through integration. ,Right now:

[0067] (11)

[0068] By using the control method of the above formula (11), compared with the voltage phase angle control method in the traditional formula (5), this embodiment can achieve effective system power suppression and achieve fast and stable operation.

[0069] At the same time, the reactive power is controlled by the reactive power control link of the virtual oscillator, that is, the voltage amplitude control in the above formula (5), to obtain the corresponding voltage amplitude.

[0070] Step S4: Calculate the system reference voltage based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, adjust the output of the three-phase converter in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

[0071] Finally, the voltage amplitude is obtained by combining the system's reactive power control loop. Calculate the reference voltage of the VOC system. The voltage and current are input to the voltage and current dual closed loop, and after passing through the PWM stage, the system closed-loop control is realized.

[0072] Based on the control strategy proposed in this embodiment, the system power suppression effect and dynamic performance can be improved by appropriately adjusting the controller coefficient. The effectiveness of the method proposed in this embodiment is further verified through the following examples.

[0073] Specifically, such as Figure 1 The three-phase converter parallel system shown consists of three converters connected in parallel. Their common terminal is connected to the power grid, and there are differences in line impedance. The distributed power sources are DG1 (5mH, 0.01Ω), DG2 (5mH, 0.05Ω), and DG3 (5mH, 0.1Ω). Figure 2 This is a structural diagram of the oscillation suppression control of a grid-type three-phase converter based on a virtual oscillator proposed in this embodiment. The virtual oscillator algorithm based on frequency feedback is shown above. The feedback frequency is compensated to the active power reference by the PD controller, thereby suppressing active power oscillations. The active power waveforms output by the improved strategy proposed in this embodiment and the original strategy are shown below. Figure 3 As shown, under conditions of inconsistent line impedance or weak damping, the active power fluctuates significantly, seriously affecting the stable operation of the system. However, after adding the power oscillation suppression method proposed in this embodiment, the power oscillation amplitude is significantly reduced during steady-state operation, and the system stability is enhanced. The effectiveness of this method is further verified by comparing the power waveforms.

[0074] Example 2

[0075] This embodiment provides a power oscillation suppression system for a multi-grid converter parallel system, including:

[0076] The signal acquisition module is used to acquire the voltage, current and voltage frequency output by the three-phase converter at the grid connection point in a multi-grid converter parallel system;

[0077] The calculation module is used to calculate the active and reactive power of the three-phase converter based on voltage and current and input it into the virtual oscillator;

[0078] The compensation module is used to obtain system power reference compensation based on the voltage frequency and rated frequency through the introduced proportional-differential controller. Then, it combines the active power and active power reference value, and obtains the frequency deviation through the active droop element of the virtual oscillator, and then calculates the voltage phase angle. At the same time, the reactive power is obtained through the reactive power control element of the virtual oscillator to obtain the voltage amplitude.

[0079] The adjustment module is used to calculate the system reference voltage based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, the output of the three-phase converter is adjusted in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

[0080] Example 3

[0081] This embodiment provides an electronic device, including: a memory for storing executable instructions; and a processor for executing the executable instructions stored in the memory to implement the method provided in this embodiment.

[0082] Example 4

[0083] This embodiment also provides a computer-readable storage medium storing executable instructions, which, when executed by a processor, will cause the processor to execute the method described above in this embodiment.

[0084] Example 5

[0085] This embodiment provides a computer program product including executable instructions, which are computer instructions; the executable instructions are stored in a computer-readable storage medium. When the processor of an electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the electronic device performs the method described in this embodiment.

[0086] The steps and methods involved in Embodiments 2 to 5 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0087] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0088] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention has been described in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that, based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A method for suppressing power oscillations in a parallel system of multi-grid converters, characterized in that, In parallel converter systems with varying line impedances, frequency feedback, combined with a proportional-derivative controller and dynamic system parameter adjustment, suppresses parallel power oscillations and achieves stable operation of multiple grid-connected converters for new energy sources. This includes: Collect the voltage, current and voltage frequency output of the three-phase converter at the grid connection point in a multi-grid converter parallel system; Based on voltage and current, calculate the active and reactive power of the three-phase converter and input them into the virtual oscillator; Based on the voltage frequency and rated frequency, the system power reference compensation is obtained through the introduced proportional-differential controller. ,for: ; Combining the active power and the active power reference value, and passing through the active power droop element of the virtual oscillator, the frequency deviation is obtained. This includes: inputting the system power reference compensation value and the active power into the active power droop element of the virtual oscillator; compensating the system power reference compensation value to the active power reference value based on the active power reference value; and calculating the frequency deviation by combining the proportional coefficient of the active power droop element. , represented as: ;in, This is the proportionality coefficient; The system frequency is calculated based on the rated frequency and frequency deviation. This system frequency is then integrated to calculate the output voltage phase angle. , represented as: ； in, To output the phase angle, The output voltage of the virtual oscillator. It is a resonant capacitor. This is the voltage-current proportionality coefficient. The natural resonant frequency, also known as the rated frequency. Indicates the frequency of real-time data acquisition. This indicates the active power output of the converter. This indicates the reference value for the active power of the converter. This is the proportionality coefficient. These are the differential coefficients. s This indicates that the input deviation signal is differentiated. Indicates a differential controller; Simultaneously, the reactive power is controlled by the reactive power control loop of the virtual oscillator to obtain the voltage amplitude; The system reference voltage is calculated based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, the output of the three-phase converter is adjusted in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

2. The power oscillation suppression method for parallel systems of multi-grid converters as described in claim 1, characterized in that, Calculate the active and reactive power of the three-phase converter based on voltage and current, including: The collected voltage and current output from the three-phase converter are subjected to Clark and Park transformations to convert the three-phase voltage and current signals into a two-phase rotating coordinate system, thus obtaining the two-phase voltage and current. Calculate the active power and reactive power of the three-phase converter based on the two-phase voltage and current.

3. The power oscillation suppression method for parallel systems of multi-grid converters as described in claim 1, characterized in that, The mathematical model of the introduced proportional-derivative controller is as follows: ； in, For the input error signal, For output signal, This is the proportionality coefficient. is the differential coefficient.

4. The power oscillation suppression method for parallel systems of multi-grid converters as described in claim 1, characterized in that, The reactive power is controlled by the reactive power control loop of the virtual oscillator to obtain the voltage amplitude, as shown in the formula: ； in, This represents the reactive power output of the converter. Given a reference voltage value, The output voltage of the virtual oscillator. It is a resonant capacitor. The convergence coefficient is . This is the voltage-current proportionality coefficient. This indicates the reference reactive power of the converter.

5. A power oscillation suppression system for parallel multi-grid converter systems, characterized in that, In parallel converter systems with varying line impedances, frequency feedback, combined with a proportional-derivative controller and dynamic system parameter adjustment, suppresses parallel power oscillations and achieves stable operation of multiple grid-connected converters for new energy sources. This includes: The signal acquisition module is used to acquire the voltage, current and voltage frequency output by the three-phase converter at the grid connection point in a multi-grid converter parallel system; The calculation module is used to calculate the active and reactive power of the three-phase converter based on voltage and current and input it into the virtual oscillator; The compensation module is used to obtain the system power reference compensation based on the voltage frequency and the rated frequency, via an introduced proportional-differential controller. ,for: ; Combining the active power and the active power reference value, and passing through the active power droop element of the virtual oscillator, the frequency deviation is obtained. This includes: inputting the system power reference compensation value and the active power into the active power droop element of the virtual oscillator; compensating the system power reference compensation value to the active power reference value based on the active power reference value; and calculating the frequency deviation by combining the proportional coefficient of the active power droop element. , represented as: ;in, This is the proportionality coefficient; The system frequency is calculated based on the rated frequency and frequency deviation. This system frequency is then integrated to calculate the output voltage phase angle. , represented as: ； in, To output the phase angle, The output voltage of the virtual oscillator. It is a resonant capacitor. This is the voltage-current proportionality coefficient. The natural resonant frequency, also known as the rated frequency. Indicates the frequency of real-time data acquisition. This indicates the active power output of the converter. This indicates the reference value for the active power of the converter. This is the proportionality coefficient. These are the differential coefficients. s This indicates that the input deviation signal is differentiated. Indicates a differential controller; Simultaneously, the reactive power is controlled by the reactive power control loop of the virtual oscillator to obtain the voltage amplitude; The adjustment module is used to calculate the system reference voltage based on the voltage amplitude and voltage phase angle. Based on the system reference voltage, the output of the three-phase converter is adjusted in real time through voltage and current dual closed-loop regulation and PWM control to suppress system frequency oscillation.

6. An electronic device, characterized in that, include: Memory, used to store executable instructions; The processor, when executing executable instructions stored in the memory, implements the power oscillation suppression method for parallel systems of multi-grid converters as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The system stores executable instructions that, when executed by a processor, implement the power oscillation suppression method for parallel systems of multi-grid converters as described in any one of claims 1-4.

8. A computer program product, characterized in that, The computer program product includes executable instructions stored in a computer-readable storage medium; When the processor of the electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions, it implements the power oscillation suppression method for parallel systems of multi-grid converters as described in any one of claims 1-4.

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