A single-phase400Hz Dynamic Voltage Restorer with PR control

As the fundamental frequency in the medium-frequency power system is 8 times 50Hz, the voltage drop has become such a problem as to affect the waveform quality of medium-frequency power supply. The medium-frequency Dynamic Voltage Restorer (DVR) can be used to eliminate the impact. In this paper, the DVR adopts the independently-controlled three H-bridge, and a precise model of one phase is established. Considering that the traditional PI control strategy cannot be applied to easily achieving a non-static error output and harmonics suppression, this paper adopts the PR controller capable of dealing with the zero steady-state error by controlling the AC signals directly. The simulation and experiment results show that the PR control strategy can effectively compensate the required voltage drop, function well in dynamic response and facilitate the adjustment of a wider bandwidth margin and that it is capable of selective compensation for low harmonic.