Research Article Open Access

Three Phase Grid Connected Photovoltaic System with Maximum Power Point Tracking

Abstract

This paper proposes a three phase grid connected photovoltaic system in which maximum power point of PV array is traced using perturb and observe algorithm. Power converter consists of a switch mode DC-DC boost converter and a neutral point clamped 3-level inverter. An overview of the dq transformation and sinusoidal PWM technique are presented for the inverter control system along with grid synchronization condition. The boost DC converter is controlled using an open loop maximum power point tracking technique in order to achieve fast control response to transients and changes in weather conditions. A DC link capacitor is used after the DC converter. The capacitor’s voltage is regulated using a DC link controller that balances input and output powers of the capacitor. The performance of the system is simulated via MATLAB SIMULINK. Furthermore, voltage source inverter is controlled in the rotating dq frame to inject a controllable three phase AC current into the grid. To achieve unity power factor operation, current is injected in phase with the grid voltage. A phase locked loop (PLL) is used to lock on the grid frequency and provide a stable reference synchronization signal for the inverter control system, which works to minimize the error between the actual injected current and the reference current obtained from the DC link controller.

Almas Hossain Mollah, G K Panda, P K Saha