A Non-linear Controller Design for UPQC in Distribution Systems

Abstract

In this article, a new approach based on non-linear control scheme was proposed for unified power quality conditioner (UPQC). The combination of sliding mode control and instantaneous active and reactive power theories was used to design this controller. UPQC consisted of a series and a shunt active power filter (APF), which were back to back connected through a common dc link capacitor. Special features of the proposed controller were as follows: 1) fast dynamic response, 2) complete compensation of UPQC by the proposed controller for the sag/swell in supply voltage, 3) good performance in power system with extreme distortions, and 4) perfect performance in compensation for unbalance networks. UPQC with the sliding mode controller (SMC) was simulated in MATLAB/SIMULINK software. Simulation results under different loads and power system conditions showed that UPQC with the proposed controller could more effectively compensate for all voltage and current distortions than the conventional PI controller.