DESIGN AND CONTROL OF STANDALONE PHOTOVOLTAIC SYSTEMS

Abstract

The design philosophy for a stand alone photovoltaic system supplying an AC load is to provide symmetrical three phase voltages with constant frequency and amplitude. This is often achieved through the introduction of a fourth leg to the usual three phase inverter, which presents severe challenges in both analysis and implementation. In this paper a control strategy incorporating a reduced order disturbance observer and feed forward disturbance canceling in the state space is presented. Simulation results for balanced and unbalanced loud show stable dynamic performance of the amplitude and frequency profiles of the output voltage. Experimental results further authenticate the proposed control technique.