A single-phase active power filter employing bidirectional power switches with safe commutation technique

This paper presents a new shunt active power filter (SAPF) topology using two bidirectional power switches. The proposed SAPF provides a new current pathway for remaining distorted current when supply voltage is supplying a nonlinear load. Pulse-width modulation (PWM) switching signal is used to shape up the remaining distorted current to be complementary to the misshapen nonlinear load current. Therefore, total input current drawn from the supply always in fully sinusoidal shape. Safe commutation strategies are well developed to prevent overcurrent spike during the transition between half positive cycle and half negative cycle of the remaining distorted current. MATLAB/SIMULINK (MLS) is used to simulate and verify the operation of the proposed SAPF. According to the simulation results, the new filter is capable to resume the original shape (sinusoidal) of the supply current and achieves less than 5% of total harmonic distortion (THD).