Inertia and Damping of DC Droop Controlled Electric Vehicle System with PLL

To reveal the inertia and damping characteristics of the electric vehicle system considering Phase Locked Loop (PLL), the research object of this paper is the two-stage electric vehicle system based on DC droop control. Based on the static synchronous generator model, the main parameters which affect the inertia level and damping effect of the electric vehicle system are analyzed. The results show that the frequency control loop, power control loop and constant voltage control loop are the main sources of inertia effect and damping effect of the system. The inertia and damping characteristics of the system can be changed by optimizing the control parameters. Adjusting the parameters of PLL in the strong power network can change the inertia and damping characteristics of the disturbance on the grid side, but it cannot change the dynamic characteristics of the energy side oscillation. The simulation results prove the correctness of the research conclusions. The conclusions of this paper are beneficial to the design of control strategy for electric vehicle system, and can also help to improve the inertia level and damping capacity of power grids.