UDE Bounded Controller Based Control Scheme of Fast Charger for Electric Vehicle Application

The electric vehicle fast charge interface is an important bridge between vehicles and power grid, and its electrical energy conversion process may bring a lot of harmonic pollution. Uncertainty and Disturbance Estimator (UDE) based control is a robust control method, which often results in instability due to saturation of the integrator. In this paper, a fast charging control strategy for EVs was presented based on the bounded UDE control method. This solution can well handle the uncertainty, disturbances, and input constraints of system between the power grid and charging pile. An additional time-varying variable is introduced into the output dynamic error of bounded controller, to naturally avoid the integrator saturation. Effectively which reduce the harmonic distortion rate of the grid-connected current, can flexibly respond to abnormal grid voltage / frequency events, and improve the stability of grid to a certain extent. The control method can effectively respond to the impact of EV fast charging interface on power grid, improve the adaptability of power grid to large-scale EV access. Based on the given control strategy, PSCAD / EMTDC is used for simulation tests, and a 50kW prototype experiment proves the correctness and effectiveness of the proposed fast charge control scheme.