Due to the existence of power coupling the virtual synchronous motor (VSG) will lead to overshoot fluctuations in the power adjustment process, thus affecting the control performance. Compared to the traditional direct current control inverter based on coordinate transformation, VSG model is more complex and difficult to achieve decoupling. This paper presents a dynamic power decoupling method by studying the coupling relationship between active power and reactive power of VSG. Firstly, the inverter grid-connected model is established, and the power expression is analyzed when the inverter output impedance is negligible. Then the virtual active power and reactive power expressions are obtained through coordinate transformation. Several key state equations and virtual states of the VSG are obtained. The power expression performs small signal perturbation to obtain the dynamic model of the VSG. From this, the dynamic model of the VSG can be analyzed to obtain the coupling relationship between the dynamic powers, and the series power compensation is used to decouple the dynamic power coupling. Finally, the correctness of the theoretical analysis and the effectiveness of the decoupling method are verified by simulation and experiments.
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