Model predictive control for suppressing frequency fluctuations in virtual synchronous generators for wind-storage island microgrid
With the increasing installed capacity of wind power systems in China,their proportion in the power grid is also growing.However,the high penetration rate of wind power brings about the issue of frequency stability in the grid.To address this,a multi-objective predictive control strategy using virtual synchronous machines(VSMs)is proposed.Currently,VSM control typically provides frequency support by setting virtual rotation equations,but it is difficult to achieve effective suppression of frequency fluctuations.To further reduce the threat of frequency fluctuations to grid stability,this paper proposes a continuous control set multi-objective optimization method based on model predictive control(MPC)principles.This method utilizes the virtual synchronous machine rotation equations to establish a power prediction model,which can predict power changes during frequency fluctuations.By designing a cost function and con-sidering output constraints,the optimal power increment is obtained.This increment is then used to modify the power command,allowing the energy storage battery system to provide more active power at the point of common coupling,thereby reducing system frequency variations.Semi-physical simulation experiments demonstrate that this method effective-ly reduces system frequency fluctuations and enhances the frequency stability of wind-storage island microgrid systems.
wind power generation systemvirtual synchronous generatormodel predictive control
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