Design Methodology, Control and Performance of a Three-Phase Grid-Tie PV Inverter under Maximum Power Point Tracking

The paper presents the controller structure of high performance, double-stage three phase grid connected solar photovoltaic (PV) system with maximum power point tracking (MPPT). In, the proposed configuration, the solar energy, after MPPT tracking, is finally channeled into a three phase AC grid by first boosting up the DC voltage level and then converting the boosted DC voltage into three-phase AC by means of a grid-tie inverter. The control of the pulse-width modulated (PWM) three phase inverter is realized similar in line with field-oriented control of electrical AC machines, using dq transformation along with feed-forward compensation. The practical and effective design steps are clearly explained to find out the controller parameters. The displacement factor at grid end is maintained unity and distortion of the current, fed into the grid, is restricted as per the IEEE-1547 standard. The analytical findings and simulation results are well agreeing.