Standalone single phase photo voltaic system as on-grid reactive power compensator

Abstract

Demand for electricity is ever increasing and the conventional sources of energy are limited. Electricity generated using photovoltaic cells is pollution free. Grid connected PV systems generate power from the sun light and supply power to utility grid. Grid connected PV system is composed of a DC/DC converter, PWM inverter and a step-up transformer. A boost converter is used to stabilize the output voltage of the PV cells, which provides power to the SPWM inverter. Zero crossing PLL is used to synchronize the inverter with the grid. The active and reactive power can be transferred by controlling the phase angle and magnitude of the inverter output voltage. The local load connected to the system will receive the active and reactive power. At the same time, reactive power can be transferred to the grid by increasing the inverter voltage slightly keeping the phase angle between inverter voltage and grid voltage zero. The variation in inverter voltage to allow reactive power compensation is restricted by the voltage tolerance of the local load. Simulation study of this system is carried out with MATLAB/Simulink toolbox and simulation results are provided.