An Optimal Fractional-Order-Proportional-Integral Controller For a Grid-Tied Photovoltaic System

This paper presents a fractional-order-Proportional-Integral controller for a grid connected Photovoltaic (PV) system. The control design is intended to achieve active and reactive power control effectively while regulating the dc-link voltage at the desired maximum power level of the PV array. Further, the power factor of the inverter output is maintained at unity without affecting the quality of the grid current (such as THD level) as per IEEE 1547 standards. The parameters of the proposed controller are optimized using particle swarm optimization. The results with the proposed optimal controller are compared with that of conventional Proportional-Integrator (PI) controller whose gains are also optimized with the same particle swarm optimization algorithm. From the comparison, it is found that the output response of proposed controller is better than the PI controller with respect to response time, settling time, overshoot and THD.