A novel fault-tolerant Shunt Active Power Filter and its control strategy

In order to increase the reliability and efficiency of Shunt Active Power Filter (SAPF), this paper proposes a novel fault-tolerant topology which can reconfigure the inverter circuit in fault condition. Redundancy operation is achieved by connecting the endpoint of fault phase to the midpoint of DC-bus. On this basis, working principle of fault-tolerant SAPF is analyzed and a control strategy which includes DC-bus voltage control and compensation current control is put forward. The DC-bus voltage control consists of stabilization control and equalization control. A compound control strategy composed of PI control and repetitive control is adopted to regulate the reference current so that both the steady-state and dynamic performance are ensured. Finally, the proposed fault-tolerant topology and its control strategy are applied to a 50kVA prototype. The experimental results have validated the efficiency and feasibility.