A universal active power filter for single-phase reactive power and harmonic compensation

In modern power distribution systems, the majority of loads draw reactive power and/or harmonic currents from the AC source along with main active power currents. These nonunity power factor linear and nonlinear loads cause low efficiency of the power supply system, poor power factor, destruction of other equipment due to excessive stresses and EMI problems. Active filters have been considered an effective solution to reduce these problems. This paper presents an active power filter (APF) based on a simple control technique to provide reactive power and harmonics compensation for linear and nonlinear single-phase loads. A voltage source inverter with carrierless hysteresis PWM current control is used to form the APF. A simple PI DC bus voltage controller with a reduced energy storage capacitor is employed in the APF. A set of lagging/leading power factor linear loads and a diode rectifier-fed capacitive load and AC voltage regulator-fed inductive load as nonlinear loads are used to demonstrate the effectiveness of the proposed APF for reactive power and harmonic compensation. The detailed steady-state and dynamic performances of the APF are presented and discussed in brief.