Abstract:
The high-power charging piles integrated into power grid are the key devices for the charging and discharging operation of electric vehicles across multiple voltage levels. However, due to the plug-and-play requirements and impulse charging power characteristics of electric vehicles, the integration of high-power charging piles will bring challenges for the stability of the grid operation. In this paper, a control strategy for high-power charging piles based on uncertainty and disturbance estimator (UDE) was proposed. First, in the dual active bridge converter (DAB) module of the high-power charging pile, the virtual direct current machinery (VDM) control strategy is adopted to realize the basic control of the DC voltage. Then, considering the impact of electric vehicle switching on the stable operation of the power grid, the UDE compensation control link is established based on the LC filter. The dynamic error of the filter unit is fed back with its output taken as the compensation component to achieve the compensation control of the DC bus voltage. In this way the stability of DC voltage can be effectively improved. Finally, by virtue of PSCAD/EMTDC software, a system simulation model with high-power charging pile is built. From the simulation analysis results the feasibility of the proposed control strategy has been verified.