Series Hybrid Active Power Filter for mitigating voltage unbalance and harmonics under unbalanced non-sinusoidal supply conditions

In the area of active power filtering, the Series Hybrid Active Power Filter (SHAPF) has been taken into account increasingly. SHAPF helps improving power quality problems like voltage unbalance, sag and swell in addition to its main objective of mitigating voltage and current type harmonics. Existing control strategies for SHAPF are based on extracting either source current harmonics or load voltage harmonics and are valid for balanced sinusoidal source conditions. In this paper a novel control scheme for SHAPF, which is based on generalised instantaneous power theory is proposed. This control scheme is valid for balanced and unbalanced, sinusoidal and non-sinusoidal source conditions and is capable of balancing load voltage while mitigating voltage or current type harmonics. The mathematical formulation of proposed control scheme with its applications to SHAPF is presented. The validity of the proposed control scheme is verified by the simulation study.