Combined control algorithm for the current quality conditioner in moderate-voltage high-power grid

Due to the limitation of voltage level and current capability of power devices, it is very difficult to handle nonlinear loads for the traditional active power filter(APF) in high-voltage high-power grid. Therefore, a novel current quality conditioner for moderate-voltage grid was researched. Based on the characteristics of the topology of the current quality conditioner, a combined control method, which was composed of current state feedback decoupling PI control and repetitive control, was put forward. In this control strategy, the PI controller for low frequency power module was used to guarantee system dynamic performance, and the repetitive controller for high frequency power module is used to improve current waveform quality. The simulation results illustrate that the performance of the proposed approach is satisfactory.