Medium frequency power supply system based on dynamic voltage restorer

The fundamental frequency of the 400Hz power supply system is 8 times 50 Hz one, so the line voltage drop becomes a severe problem that affects the output voltage quality of the medium frequency power supply system. In a power supply system with single power source and multiple loads, as different lines between loads and power source are different in length, series dynamic voltage restorers (DVR) are set at the loads side to keep loads voltage constant in this paper. By means of analyzing impedance of transmission line and the voltage drop on it, a capacity calculation model of dynamic voltage restorer under normal working conditions is found. The series dynamic voltage restorer based on proportional-resonant (PR) control is used to guarantee a satisfactory output quality of the system. Simulation and experiment results verify that the series dynamic voltage restorer based on PR control effectively solves the problems of source voltage perturbation and line voltage drop in the medium frequency power supply system.