Mitigation of unbalanced disturbances using hybrid controller

A hybrid controller that combines PI controller and variable structure control is proposed in this thesis. The output of the controller is given to a grid connected pulse width-modulated voltage-source inverters (VSIs). The linear and non linear loads are connected to the point of common coupling(PCC). The voltage and current fluctuations at the PCC is analysed. To ensure fast regulation of voltage at the point of common coupling (PCC) and to provide power quality supply this hybrid controller is proposed. Subsequently, a wide range of voltage perturbations, including capacitor-switching disturbances, can be rejected. The dc input to inverter is given by fuel cell which is a distributed generation(DG). When inverter is on the necessary active power supply is provided to load by this DG. The thesis work investigates the efficiency of the hybrid controller to regulate voltage at PCC with balanced and unbalanced loads. MATLAB/Simulink is used to develop the model.