Capacitor Voltage Regulation in Shunt Active Power Filter using Sliding Mode Controller

Nowadays power quality problem is a very important issue in power sector and various methods are developed to mitigate them. Shunt active power filter (APF) is used for current harmonics compensation. Synchronous Reference Frame theory is used for control of Shunt APF. In case of Voltage Source Inverter (VSI) based Shunt APF capacitor is used as energy source element. So, the performance of Shunt APF is entirely dependent on capacitor voltage regulation. Traditional approach which uses PI controller has slow response, has overshoot & settling time is also high. A new control approach which uses Sliding mode technique is proposed. This control approach uses Power Rate reaching law. So the settling time improves with no overshoot. Also the stability of overall system is examined by giving step change in load. Simulation results are given which shows validity of proposed approach.