The Coordinated Control Strategy for Virtual Synchronous Generator of PV Stations and VSC-HVDC Without Communication

Multiple large-scale PV station will supply power through voltage source converter based HVDC (VSC-HVDC) transmission,and inertia response of VSC-HVDC is beneficial for enhancing the transient stability of receiving end of power grid. In this paper,the control strategy of VSC-HVDC is analyzed, and a novel control strategy of coordinated virtual synchronous generator (VSG) of PV stations and VSC-HVDC which does not rely on communications is presented as to the frequency variation of receiving end of power grid. The coupling between the frequency of the receiving end of power grid and the voltage amplitude of the sending end of power grid is obtained through the variable voltage control of the sending end converter if the disturbing occurs at receiving end of power grid.The power controller of PV inverter will influence the voltage variation of the sending end converter of HVDC, and regulate the instruction value of output power.At the same time,the real power balance between the PV stations and HVDC is achieved, and the HVDC system can keep its DC voltage unchanged under the steady state when applying the VSG control scheme. Simulation model is built by using MATLAB/SIMULINKsimulation software, which verifies the validity of the proposed control strategy.