Comparative evaluation of various single phase harmonic filters for non-linear load

Majority of loads draw non-sinusoidal current from the supply, resulting in the generation of current and voltage harmonics. The presence of the harmonics leads to low system efficiency, poor power factor, increased losses and reactive power components of current from AC mains. In this paper a comparative study of current harmonic compensation using passive power filter, Shunt active power filter and hybrid filter is made. In hybrid filter, two single tuned passive filters are tuned to compensate 3^rd and 5^th order harmonics and active power filter compensates all remaining harmonic components which are not compensated by passive filter. A voltage source inverter with hysteresis current control is used to form an active power filter and it is injecting equal but opposite current to mitigate the distortion current to shape the supply current to a sinusoidal form and in phase with the supply voltage. A simple PI dc bus voltage controller with reduced energy storage capacitor is employed in the APF. A fixed non linear load is simulated with various harmonic filters in MATLAB/Simulink environment. The results show that use of Hybrid Filter provides better performance simultaneously reducing the required device rating.