PLL Synchronization with PID Controller BasedShunt Active Power Line Conditioners

Abstract

Abstract-This paper describes Shunt Active Power Line Conditioners (APLC) for compensating harmonic currents and reactive power drawn by the non-linear loads besides power factor correction. The shunt APLC is implemented with three phase PWM current controlled voltage source inverter and is connected at the point of common coupling (PCC) for compensating the harmonics. The compensation process is based on phase locked loop (PLL) synchronization with proportional integral derivative (PID) controller. These control strategies for shunt APLC makes certain that source current is sinusoidal even when the load is non-linear and unbalanced. The PWM-VSI inverter switching is done according to gating signals derived from hysteresis band current controller (HCC) and the capacitor voltage is maintained constant using PID controller. The proposed shunt APLC is investigated using extensive simulation and is found to be effective in terms of THD, reactive power compensation and VDC settling time under various balanced and unbalanced load conditions.