Research on topology and control of DC energy-storageless dynamic voltage restorer

This paper proposes an improved dynamic voltage restorer based on DC energy-storageless direct AC/AC converter. The working principle and non-complementary control commutation strategy are analyzed. The novel predictive control based on a discrete state observer is designed. On the one hand, without the use of energy storage devices like electrolytic capacitor, the proposed dynamic voltage restorer is easy to maintain compared to traditional dynamic voltage restorer with voltage source inverter, which can reduce the weight and cost. On the other hand, the predictive control strategy makes the load voltage stable when the grid voltage fluctuations occur, thus the ability of dynamic response is improved. Simulation results verify the validity of the proposed plan.