A novel control strategy for capacitor voltage regulation of Unified Power Quality Conditioner using Integral plus Sliding Mode Controller

Increased use of non-linear loads in industries causing voltage and current distortions. Unified Power Quality Conditioner (UPQC) is used at Distribution level to compensate voltage as well as current distortion problems at a time. In order to ensure the better operation of UPQC, the DC-Link capacitor voltage must be maintained constant. Traditional Pi-controller shows overshoot in response. Also, the Sliding Mode Controller (SMC) designed using traditional approach exhibits steady-state error. This offset can be removed by adding a constant in SMC law. But this approach can't work for UPQC system, when load is change. In this paper, a novel capacitor voltage regulator is proposed using Integral plus Sliding Mode Control technique. The proposed controller has the inherent advantages like has very low Settling Time with no overshoot. This controller completely eliminates steady-state error. The simulation results are given considering various control strategies, shows validation of proposed technique.