DC charging pile control method based on improved virtual inertia control

The advantages of fast charging speed and high efficiency of DC charging piles make the connection and cutting of electric vehicle (EV) loads relatively frequent. However, as a DC system, DC charging pile has the characteristics of low inertia and weak damping. In order to reduce the impact of EV load connection and cutting on the DC side voltage disturbance, a DC charging pile control method based on improved virtual inertia (VI) control is proposed. This paper firstly introduces VI control by analogy with virtual synchronous machines (VSM) technology. Secondly, the VI control is improved by using command filter backstepping integral sliding mode (CFBISM) control, in which the integral sliding mode (ISM) control is used to optimize the VI control to enhance the robustness of the system, and the command filter backstepping control is used to reconfigure the key parameters to avoid the computational inflation of the controller, while the ISM control is used to improve the current inner loop to further enhance the control effect. The stability of the proposed control strategy is then demonstrated by the Lyapunov stability criterion. Finally, through comparative simulation, it is verified that the DC-side voltage fluctuation can be limited within 2 V, the dynamic response speed is improved by about 0.1 s, and the perturbation of the key parameters in the steady state is limited to about 1 V, thus the superiority of the fast response speed and good robustness of the control proposed in this paper are verified by simulation.