A Bidirectional Control Principle of Active Tuned Hybrid Power Filter Based on the Active Reactor Using Active Techniques

In this paper, a novel bidirectional control principle of active tuned hybrid power filter (ATHPF) based on the active reactor using active techniques is proposed. The proposed control principle, in essence, is to continuously adjust the filter inductance of the active reactor by regulating active power filter (APF) output current in terms of its magnitude and direction. Therefore, the ATHPF using the bidirectional control principle can simultaneously supply different impedances at different selective suppressed harmonic frequencies. The bidirectional control principle can perform both the normal active tuning function and the abnormal active detuning function. To be specific, the normal active tuning function refers to the harmonic elimination with filtering performance independent of the deviation of passive filter parameters, while the latter, the abnormal active detuning function, refers to the flexible protection against harmonic over-current without losing two harmonic elimination and reactive power compensation at the occurrence of harmonic over-current. Experimental results verify the effectiveness of the ATHPF with the bidirectional control principle in selective harmonic elimination and flexible protection against harmonic over-current.