A series-connected voltage source converter for voltage sag mitigation using vector control and a filter compensation algorithm

In this paper, a series-connected VSC for voltage sag mitigation is presented, which is characterized by a fast control logic, based on the decomposition of the unbalanced supply voltages into instantaneous positive and negative sequence components in two different rotating dq-coordinate systems. Furthermore, its performance is improved through the implementation of an algorithm to compensate for the steady-state voltage drop on the converter output filter. The operation of the whole system subject to an unbalanced sag has been simulated and tested by using measured sag data, recorded by a power quality monitor. Simulation results show the effectiveness of the proposed algorithm