Analysis on the Contribution of Virtual Synchronous Generator Controlled Energy Storage System to Primary Frequency Modulation

Abstract

Virtual Synchronous Generator (VSG) control has been applied to the Energy Storage System (ESS) to improve its frequency response characteristics. However, the influence mechanism of the control parameters of the VSG controlled ESS on the primary frequency modulation has not been analyzed in depth. An analysis method of the influence of the control parameters of the VSG controlled ESS on the primary frequency modulation is proposed in this paper. The VSG control scheme of the ESS is briefly introduced and then the exact differential equation for the primary frequency modulation of the power system is established. By solving this differential equation, the complete frequency response curve in the primary frequency modulation process of the power system is obtained. Therefore, it is possible to further analyze the influence of different control parameters on the frequency response during a frequency modulation process. Moreover, when the State of Charge (SOC) of the ESS reaches the limit during charging and discharging, it will cause a secondary change in frequency. This phenomenon is also analyzed and the corresponding solutions is given. Finally, the simulation results verify the effectiveness of the analysis method proposed in this paper.