High precision compensation for high power Hybrid Active Power Filter based on repetitive control algorithm

Hybrid Active Power Filter (HAPF), which consists of Passive Power Filter (PPF) and Active Power Filter (APF) in series, is suitable for large capacity and high voltage application. Conventional controllers e.g. PI and proportional resonant ones etc., have their disadvantages diversely to control the output voltage of the APF part as a controlled harmonic voltage source as desired, which is crucial to the whole HAPF. In this paper, a high-performance control strategy based on PI-inner and repetitive-control-external loop is firstly adopted into the HAPF. Compared to mere PI controller, it has wider bandwidth and smaller phase lag. As a result, it can tremendously improve the harmonic compensation precision. Configuration, modeling and parameters optimization are analyzed. Design method of the proposed double-loop controller is also given in details. Simulation results show that it can not only effectively improve the accuracy of steady-state compensation, but also guarantee good dynamic performance.