A method, system and device for improving small signal stability of a grid-connected converter based on phase reconstruction of the converter

Abstract

The present application relates to the field of new energy grid-connected converter control technology, and more particularly to a grid-following converter small disturbance stability improvement method based on converter phase reconstruction. The method is aimed at the problem that the grid-following converter is prone to small disturbance oscillation when operating in a weak grid due to the coupling of the phase-locked loop synchronization branch and the power regulation link. On the basis of retaining the main structure of the grid-following control, a grid-forming droop synchronization branch is introduced, and the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate a reconstructed control phase angle. The reconstructed control phase angle is used to replace the phase-locked loop phase angle as the phase reference for the coordinate transformation and control modulation of the converter. By adjusting the fusion coefficient, the proportion of the phase-locked loop phase disturbance in the final control phase angle can be reduced, and the system damping can be enhanced, so that the grid-following converter can maintain stable operation under weak grid small disturbance conditions.

Description

Technical Field

[0001] This invention belongs to the fields of new energy grid-connected converter control, power electronic converter synchronous control, and power system small disturbance stability control technology, specifically involving a method for improving the small disturbance stability of grid-connected converters based on converter phase reconstruction. Background Technology

[0002] With the large-scale integration of power electronic grid-connected equipment such as wind power, photovoltaics, and energy storage, grid-connected converters are gradually becoming the core interface for interaction between new energy units and the power grid. Grid-connected converters typically rely on phase-locked loops (PLLs) to obtain the voltage phase at the grid connection point and use the PLL output phase angle as the synchronization reference for coordinate transformation and modulation control.

[0003] Under strong grid conditions, the voltage phase at the grid connection point is relatively stable, and the phase-locked loop (PLL) can provide a reliable synchronization reference. However, in weak grid conditions or scenarios with high grid impedance, small disturbances in the converter's output current and power can cause changes in the voltage phase at the grid connection point. After the PLL tracks this phase disturbance, it affects the converter's current control and power output, easily leading to coupling feedback between the PLL synchronization stage and the power regulation stage. This results in reduced system damping and even small-disturbance oscillation instability. Grid-based control does not rely on the PLL to directly track the grid phase but actively forms voltage phase and frequency references through droop control, virtual synchronization control, etc., providing strong voltage and damping support capabilities. Therefore, introducing the phase generation characteristics from grid-based control into the synchronization stage of the grid-connected converter and reconstructing the PLL output phase angle helps to reduce the impact of grid connection point phase disturbances on the control phase angle and improves the small-disturbance stability of the grid-connected converter under weak grid conditions.

[0004] Existing research, such as Zhou Yuqing et al.'s "Optimal Configuration Method of Switchable Units for Grid Connection / Connection in New Energy Power Plants Based on Operating Short-Circuit Ratio," points out that configuring a small number of switchable units for grid connection / connection in fully grid-connected power plants and using the operating short-circuit ratio as the switching indicator can improve the stable operation capability of new energy power plants under weak grid conditions. However, this method mainly focuses on grid connection / connection mode switching and switchable unit capacity configuration at the power plant level, relying on information such as operating short-circuit ratio, grid impedance identification, or power plant power measurement. It does not develop a phase reconfiguration control method for a single grid-connected converter. Therefore, a control method is still needed that, without changing the main control structure of the grid-connected converter, weakens the impact of phase-locked loop phase disturbances and improves small-disturbance stability by reconfiguring the control phase angle. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving the stability of grid-connected converters under small disturbances based on converter phase reconstruction, so as to solve the problems of insufficient system damping, small disturbance oscillation or even instability caused by the coupling of phase tracking and power regulation of phase-locked loop in traditional grid-connected converters under weak grid conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for improving the stability of grid-connected converters under small disturbances based on converter phase reconstruction, the method being applied to grid-connected converters or new energy power generation units containing grid-connected converters, the method comprising the following steps:

[0008] S1. Collect grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control.

[0009] S2. Obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ;

[0010] S3. Based on the converter output active power and active power reference value, obtain the droop angular frequency ω of the droop synchronous branch output. dp and drooping phase angle θ dp ;

[0011] S4. Determine the fusion coefficient k used for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value of the converter output active power (P). h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches;

[0012] S5. Based on the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r The reconstructed control phase angle θ is obtained by integrating the reconstructed synchronization angular frequency. r ;

[0013] S6, using the reconstructed control phase angle θ r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter;

[0014] S7. Repeat S1 to S6 in each control cycle to make the reconfigured control phase angle update in real time with the system operating status, thereby improving the small disturbance stability of the grid-type converter.

[0015] The phase-locked loop synchronization branch outputs the initial synchronization angular frequency ω based on the q-axis component of the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL And satisfy:

[0016]

[0017]

[0018] In the formula, ω0 is the rated angular frequency. For the Laplace operator, k ppll and k ipll These are the proportional and integral coefficients of the phase-locked loop, k. ppll Values ​​50 and k ipll Value 500, u gqref u is the reference value for the q-axis voltage. gq This represents the q-axis component of the grid connection point voltage.

[0019] In S3, the drooping synchronous branch is based on the active power reference value P. ref With the active power P output by the converter g The deviation between the output droop frequency ω dp and drooping phase angle θ dp And satisfy:

[0020]

[0021]

[0022] In the formula, k dp This is the droop control coefficient.

[0023] In step S4, the per-unit value P of the converter output active power is based on the converter output active power P g With the rated active power P of the converter N The expression is:

[0024]

[0025] In S4, the fusion coefficient k h The value range of is 0 to 1, and the fusion coefficient k h The calculation formula is determined based on the short-circuit ratio (SCR) at the grid connection point and the per-unit value P of the converter output active power, and includes:

[0026]

[0027] In the formula, k SCR k is the fusion component corresponding to the short-circuit ratio. p This is the fused component corresponding to the output power.

[0028] In step S5, the synchronization angular frequency ω is reconstructed. r and reconfiguration control phase angle θ r satisfy:

[0029]

[0030]

[0031] In step S6, the control phase angle θ is reconstructed. r It is used for coordinate transformation between a three-phase stationary coordinate system and a synchronous rotating coordinate system, and for use in the inner current loop, outer voltage loop, power control loop, or pulse width modulation circuit.

[0032] A system for improving the stability of a grid-connected converter under small disturbances based on converter phase reconstruction, the system comprising:

[0033] The signal acquisition module is used to acquire grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control.

[0034] The phase-locked loop synchronization branch module is used to obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ;

[0035] The drooping synchronous branch module is used to determine the active power P output by the converter. g With active power reference value P ref The deviation between them is used to obtain the droop angular frequency ω of the droop synchronization branch output. dp and drooping phase angle θ dp ;

[0036] The fusion coefficient calculation module is used to determine the fusion coefficient k for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value P of the converter output active power. h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches;

[0037] Phase reconstruction module, used to determine the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r And the reconstructed synchronization angular frequency ω rIntegrating, we obtain the reconstructed control phase angle θ. r ;

[0038] The control command generation module is used to reconstruct the control phase angle θ. r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter;

[0039] In each control cycle, the system repeatedly executes the processing procedures of the above modules to reconstruct the control phase angle θ. r Updated in real time according to the system's running status; each module is configured to execute the corresponding steps in the aforementioned method.

[0040] An electronic device includes a processor, a memory, and a control program stored in the memory and executable by the processor, wherein the processor executes the control program to perform the aforementioned method.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. This invention reduces the direct dominance of the phase-locked loop output phase angle on the final control coordinate system by reconstructing the converter control phase angle, thereby weakening the coupling between the phase-locked loop and power regulation under weak grid conditions and improving the small-disturbance stability of the grid-connected converter under weak grid conditions.

[0043] 2. This invention introduces a drooping synchronous branch while retaining the main control structure of the grid-type converter. This eliminates the need to completely transform the converter into a grid-type control system, which helps to reduce the difficulty of control transformation.

[0044] 3. This invention utilizes the fusion coefficient k h The weights of the phase-locked loop synchronization branch and the droop synchronization branch are continuously allocated to avoid phase angle abrupt changes and control shocks caused by switching between traditional control modes.

[0045] 4. This invention is applicable to grid-connected converters for various new energy sources such as wind power, photovoltaics, and energy storage, and can also be applied to field station-level grid-connected controllers. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating a method for improving the stability of a grid-connected converter under small disturbances based on converter phase reconstruction, according to the present invention.

[0047] Figure 2 This is a control block diagram of the grid-connected system of the present invention;

[0048] Figure 3 This is a schematic diagram of the phase reconstruction control structure of the present invention;

[0049] Figure 4This is a surface plot showing the variation of the fusion coefficient under the combined effect of short-circuit ratio and output power in this invention;

[0050] Figure 5 This is a simulation comparison diagram of the active power response of the system according to the present invention;

[0051] Figure 6 This is a simulation diagram of the system active power corresponding to different SCR conditions of the present invention. Detailed Implementation

[0052] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0053] This invention relates to a method for improving the small-disturbance stability of grid-connected converters based on converter phase reconstruction. The method is applied to grid-connected converters or new energy power generation units containing grid-connected converters, such as... Figure 1 As shown, the method includes the following steps:

[0054] S1. Collect grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control.

[0055] S2. Obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ;

[0056] S3. Based on the converter output active power and active power reference value, obtain the droop angular frequency ω of the droop synchronous branch output. dp and drooping phase angle θ dp ;

[0057] S4. Determine the fusion coefficient k used for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value of the converter output active power (P). h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches;

[0058] S5. Based on the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r The reconstructed control phase angle θ is obtained by integrating the reconstructed synchronization angular frequency. r ;

[0059] S6, using the reconstructed control phase angle θ r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter;

[0060] S7. Repeat S1 to S6 in each control cycle to make the reconfigured control phase angle update in real time with the system operating status, thereby improving the small disturbance stability of the grid-type converter.

[0061] The phase-locked loop synchronization branch outputs the initial synchronization angular frequency ω based on the q-axis component of the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL And satisfy:

[0062]

[0063]

[0064] In the formula, ω0 is the rated angular frequency. For the Laplace operator, k ppll and k ipll These are the proportional and integral coefficients of the phase-locked loop, k. ppll Values ​​50 and k ipll Value 500, u gqref u is the reference value for the q-axis voltage. gq This represents the q-axis component of the grid connection point voltage.

[0065] In S3, the drooping synchronous branch is based on the active power reference value P. ref With the active power P output by the converter g The deviation between them outputs the droop frequency ω dp and drooping phase angle θ dp And satisfy:

[0066]

[0067]

[0068] In the formula, k dp This is the droop control coefficient.

[0069] In step S4, the per-unit value P of the converter output active power is based on the converter output active power P g With the rated active power P of the converter N The expression is:

[0070]

[0071] In S4, the fusion coefficient k h The value range of is 0 to 1, and the fusion coefficient k hThe calculation formula is determined based on the short-circuit ratio (SCR) at the grid connection point and the per-unit value P of the converter output active power, and includes:

[0072]

[0073] In the formula, k SCR k is the fusion component corresponding to the short-circuit ratio. p This is the fused component corresponding to the output power.

[0074] like Figure 4 As shown, the fusion coefficient k h It is continuously adjusted according to changes in the short-circuit ratio (SCR) and the per-unit output power (P). When the SCR is low, the grid strength is weak, and the fusion coefficient k... h A larger drooping synchronous branch increases its weight in the reconfiguration control phase angle; when the short-circuit ratio (SCR) is high, the fusion coefficient k... h The smaller the output power per unit (P), the more the system retains the fast synchronization characteristics of the phase-locked loop (PLL) synchronization branch. Meanwhile, as the per-unit output power (P) increases, the impact of converter output current and power disturbances on the grid connection voltage phase intensifies, increasing the fusion coefficient (k). h This increases the weight of the drooping synchronization branch, thereby reducing the impact of the phase-locked loop synchronization branch on the final control phase angle.

[0075] In step S5, the synchronization angular frequency ω is reconstructed. r and reconfiguration control phase angle θ r satisfy:

[0076]

[0077]

[0078] In step S6, the control phase angle θ is reconstructed. r It is used for coordinate transformation between a three-phase stationary coordinate system and a synchronous rotating coordinate system, and for use in the inner current loop, outer voltage loop, power control loop, or pulse width modulation circuit.

[0079] This invention also relates to a system for improving the stability of a grid-connected converter with small disturbances based on converter phase reconstruction, the system comprising:

[0080] The signal acquisition module is used to acquire grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control.

[0081] The phase-locked loop synchronization branch module is used to obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ;

[0082] The drooping synchronous branch module is used to determine the active power P output by the converter. g With active power reference value P ref The deviation between them is used to obtain the droop angular frequency ω of the droop synchronization branch output. dp and drooping phase angle θ dp ;

[0083] The fusion coefficient calculation module is used to determine the fusion coefficient k for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value P of the converter output active power. h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches;

[0084] Phase reconstruction module, used to determine the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r And the reconstructed synchronization angular frequency ω r Integrating, we obtain the reconstructed control phase angle θ. r ;

[0085] The control command generation module is used to reconstruct the control phase angle θ. r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter;

[0086] In each control cycle, the system repeatedly executes the processing procedures of the above modules to reconstruct the control phase angle θ. r Updated in real time according to the system's running status; each module is configured to execute the corresponding steps in the aforementioned method.

[0087] The present invention also relates to a small-disturbance stability improvement device for grid-connected converters based on converter phase reconstruction, comprising a processor, a memory, and a control program stored in the memory and executable by the processor. The control device is used in a grid-connected converter or a new energy power generation unit containing a grid-connected converter, and the processor executes the aforementioned method.

[0088] The core of this invention lies in reconstructing the converter control phase angle by weighted fusion of the phase-locked loop (PLL) synchronization branch and the drooping synchronization branch. Traditional grid-connected converters typically use the PLL output phase angle directly as the control phase angle. When the voltage phase at the grid connection point is affected by weak grid impedance and power disturbances, the PLL output phase angle will fluctuate accordingly, thus affecting coordinate transformation, current control, and power output, forming a coupling between the PLL and the power loop.

[0089] This invention introduces a drooping synchronization branch, so that the converter control phase angle is determined not only by the phase-locked loop branch but also includes the synchronization component provided by the drooping branch. When the fusion coefficient k... h When the weight increases, the weight of the drooping synchronization branch in the reconstructed control phase angle increases, the weight of the phase-locked loop synchronization branch decreases, and the impact of the phase-locked loop phase disturbance on the final control phase angle weakens accordingly.

[0090] Furthermore, the present invention can use the grid connection point short-circuit ratio (SCR) and the per-unit value of the converter output active power (P) as the fusion coefficient k. h The tuning basis. When SCR decreases or P increases, k h Increasing the phase angle allows for the introduction of more droop synchronization components into the reconfiguration control phase angle, thereby enhancing system damping.

[0091] Table 1 shows the fusion coefficient k. h The typical meaning of .

[0092] Table 1. Correspondence between fusion coefficient and converter phase reconfiguration characteristics

[0093] <![CDATA[fusion coefficient k h > Phase reconstruction features Instructions for use 0 Phase-locked loop phase angle Traditional grid synchronization is suitable for strong power grids or scenarios with weak disturbances. <![CDATA[0<k h <1]]> Weighted fusion of phase-locked loop branches and droop branches Reconstructing the control phase angle to balance grid synchronization and damping enhancement 1 Adopting drooping synchronous phase angle Network synchronization is suitable for weak power grids or scenarios with low stability margins.

[0094] As shown in Table 1, the fusion coefficient k h The larger the value, the stronger the influence of the drooping synchronization branch on the reconfiguration control phase angle, and the more significant the system damping enhancement effect; the fusion coefficient k h When the system is smaller, it is closer to the traditional method of synchronizing with the network.

[0095] The following experimental diagrams illustrate this in detail:

[0096] like Figure 5 As shown, in the original grid control method, the active power gradually exhibits divergent oscillations after the system is subjected to a small disturbance; after adopting the present invention, the active power only fluctuates briefly in the early stage of the disturbance, and then gradually converges to a stable value.

[0097] like Figure 6 As shown, under different short-circuit ratios, the active power of the system using this invention can gradually converge to a stable value after a small disturbance. As the short-circuit ratio (SCR) decreases, the system oscillation amplitude increases and the convergence time prolongs; as the SCR increases, the system oscillation amplitude decreases and the convergence speed accelerates.

[0098] Combination Figure 5 and Figure 6It is evident that, after adopting this invention, the system's active power response transforms from a divergent oscillation state under grid-connected control to a convergent stable state, and maintains oscillation convergence under different short-circuit ratios. This is because the invention reduces the influence of PLL phase disturbances on the final control phase angle by weighted fusion reconstruction of the PLL synchronous branch and the droop synchronous branch, thereby weakening the coupling between the PLL and the power regulation stage, enhancing system damping, and improving the small-disturbance stability of the grid-connected converter under weak grid operating conditions.

Claims

1. A method for improving the small-disturbance stability of a grid-connected converter based on converter phase reconstruction, the method being applied to a grid-connected converter or a new energy power generation unit containing a grid-connected converter, characterized in that, The method includes the following steps: S1. Collect grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control. S2. Obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ; S3. Based on the converter output active power and active power reference value, obtain the droop angular frequency ω of the droop synchronous branch output. dp and drooping phase angle θ dp ; S4. Determine the fusion coefficient k used for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value of the converter output active power (P). h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches; S5. Based on the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r The reconstructed control phase angle θ is obtained by integrating the reconstructed synchronization angular frequency. r ; S6, using the reconstructed control phase angle θ r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter; S7. Repeat S1 to S6 in each control cycle to make the reconfigured control phase angle update in real time with the system operating status, thereby improving the small disturbance stability of the grid-type converter.

2. The method according to claim 1, characterized in that, In step S2, the phase-locked loop synchronization branch outputs the initial synchronization angular frequency ω based on the q-axis component of the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL And satisfy: In the formula, ω0 is the rated angular frequency. For the Laplace operator, k ppll and k ipll These are the proportional and integral coefficients of the phase-locked loop, k. ppll Values ​​50 and k ipll Value 500, u gqref u is the reference value for the q-axis voltage. gq This represents the q-axis component of the grid connection point voltage.

3. The method according to claim 1, characterized in that, In S3, the drooping synchronous branch is based on the active power reference value P. ref With the active power P output by the converter g The deviation between them outputs the droop frequency ω dp and drooping phase angle θ dp And satisfy: In the formula, k dp This is the droop control coefficient.

4. The method according to claim 1, characterized in that, In step S4, the per-unit value P of the converter output active power is based on the converter output active power P g With the rated active power P of the converter N The expression is:

5. The method according to claim 1, characterized in that, In S4, the fusion coefficient k h The value range of is 0 to 1, and the fusion coefficient k h The calculation formula is determined based on the short-circuit ratio (SCR) at the grid connection point and the per-unit value P of the converter output active power, and includes: In the formula, k SCR k is the fusion component corresponding to the short-circuit ratio. p This is the fused component corresponding to the output power.

6. The method according to claim 1, characterized in that, In step S5, the synchronization angular frequency ω is reconstructed. r and reconfiguration control phase angle θ r satisfy:

7. The method according to claim 1, characterized in that, In step S6, the control phase angle θ is reconstructed. r It is used for coordinate transformation between a three-phase stationary coordinate system and a synchronous rotating coordinate system, and for use in the inner current loop, outer voltage loop, power control loop, or pulse width modulation circuit.

8. A system for improving the stability of a grid-connected converter under small disturbances based on converter phase reconstruction, characterized in that, The system includes: The signal acquisition module is used to acquire grid connection point voltage, grid connection current, grid connection point short-circuit ratio (SCR), and the operating quantities required for converter control. The phase-locked loop synchronization branch module is used to obtain the initial synchronization angular frequency ω of the phase-locked loop synchronization branch output based on the grid connection point voltage. PLL and the initial synchronization phase angle θ PLL ; The drooping synchronous branch module is used to determine the active power P output by the converter. g With active power reference value P ref The deviation between them is used to obtain the droop angular frequency ω of the droop synchronization branch output. dp and drooping phase angle θ dp ; The fusion coefficient calculation module is used to determine the fusion coefficient k for phase reconfiguration based on the grid connection point short-circuit ratio (SCR) and the per-unit value P of the converter output active power. h , where k h For the weights of the drooping synchronous branches, 1-k h The weights of the phase-locked loop synchronization branches; Phase reconstruction module, used to determine the fusion coefficient k h The output angular frequencies of the phase-locked loop synchronization branch and the droop synchronization branch are weighted and fused to generate the reconstructed synchronization angular frequency ω. r And the reconstructed synchronization angular frequency ω r Integrating, we obtain the reconstructed control phase angle θ. r ; The control command generation module is used to reconstruct the control phase angle θ. r Replace the initial synchronization phase angle θ PLL As a phase reference for coordinate transformation and control modulation of the grid-connected converter, it generates current, voltage or power control commands for the grid-connected converter; In each control cycle, the system repeatedly executes the processing procedures of the above modules to reconstruct the control phase angle θ. r The system updates in real time according to its operating status; each module is configured to execute the corresponding step in the method described in any one of claims 1-7.

9. An electronic device, characterized in that, The method includes a processor, a memory, and a control program stored in the memory and executable by the processor, wherein the processor, when executing the control program, implements the method according to any one of claims 1-7.

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