Analysis of Compensation Strategies for Dynamic Voltage Restorer Based on DSFR-PLL Control

Dynamic voltage restorer (DVR) has been considered to be a cost-effective custom power device, which alleviates voltage sags. Recently, the uninterrupted dynamic voltage restorer (UDVR), which is one of the four topologies of DVR, is more used. According to the loads’ sensitivity to voltage amplitude and phase jump, UDVR adopts different compensation strategies. This paper presents the pre-sag compensation strategy and in-phase compensation strategy based on decoupled synchronous frame phase-locked loop (DSRF-PLL). Then, an improved integrated compensation strategy is proposed. The simulation test with Matlab/Simulink for single-phase voltage sag compensation verifies that the proposed strategy, compared with in-phase compensation, can mitigate the phase jump accompanied voltage sags. And the simulation results also verify that the proposed strategy can decrease the amplitude of injected UDVR voltage, compared with pre-sag compensation strategy.