Active power filter with sliding mode control

The paper presents an active power filter (APF) to eliminate harmonics and to compensate reactive power and neutral current of three-phase four-wire symmetrical and unbalanced nonlinear loads. A set of three single-phase insulated-gate bipolar transistor (IGBT)-based voltage source inverter (VSI) bridges with a common DC bus capacitor is used as the APF. A sliding mode controller (SMC) over the average DC bus voltage is used for the control. A hysteresis rule bused carrierless pulse width modulation (PWM) current control is employed to generate the gating signals to the switching devices. A set of three single-phase diode bridge rectifiers with capacitive-resistive loading is used for nonlinear loading. The simulation results show that the APF is capable of compensating reactive power. Neutral current and load unbalance and reducing the harmonic level below the limit specified in IEEE-519 standard