Proportional-repetitive control of a dynamic voltage restorer (DVR) for power quality improvement

This paper discusses a controller based on a proportional-repetitive control for a dynamic voltage restorer (DVR). Repetitive control can achieve zero steady-state error of tracking sinusoidal signal, but it doesn´t make a quick response to the disturbance and needs at least one fundamental cycle to function properly. The control system based on proportional-repetitive controller, in stationary frame is proposed to achieve fast dynamic response and zero steady-state error at the same time. This controller can compensate power quality disturbances, such as voltage sag, harmonic voltages, and voltage imbalance, simultaneously. The control scheme is implemented in a test system with PSCAD/EMTDC software. Simulation results show that the output voltage of controller can track the reference signal quickly and accurately and therefore compensate disturbances.