(State Key Laboratory of Power Transmission Equipment and System Security and New Technology (Chongqing University), Chongqing 400044, China)

For the control of virtual synchronous generator(VSG)of grid-connected inverter, an approach is proposed to estimate the produced inertia and damping of VSG. Thus, the capability of VSG to participate in power grid adjustment can be quantified. Based on the second-order nonlinear model of VSG and its small signal perturbation processing ability near the working point, a linearized model for VSG is proposed. The discrete model of the linearized model is derived and its relation with inertia and damping parameters of VSG is given. The error magnitude and effective range of the linearized model are proposed. Using the output power step disturbance of VSG, the modal information on power oscillation of VSG is energized. Then, the least-square method is utilized to estimate actual inertia and damping parameters of VSG. Finally, by taking the normal control and VSG control into account, simulated results and experimental measurements have confirmed the possibility and effectiveness of the proposed model and approach. This work is supported by Chongqing Research Program of Basic Research and Frontier Technology(No. cstc2016jcyjA0108), Fundamental Research Funds for the Central Universities(No. 106112015CDJXY150005)and State Grid Corporation of China(No. SGHADK00PJJS1500060).