Experimental validation of sliding mode-predictive direct power control of a grid connected photovoltaic system, feeding a nonlinear load

This paper presents an experimental performances improvement of a three-phase double-stage grid connected photovoltaic system, associated with a parallel Active Power Filter (APF). In order to control the first conversion stage, a sliding mode algorithm is proposed to track the maximum power point (MPP) of the photovoltaic (PV) array regardless atmospheric changing, while the second stage control is performed via a predictive direct power control (P-DPC) to both injecting the extracted active power into the grid, and compensating undesirable harmonic components caused by the nonlinear, under a unity power factor functioning. The implementation of the control strategies is achieved on a small scale PV system, controlled via a dSPACE 1104 single card. The obtained experimental results show that the proposed control strategies provide fast and high performances under different irradiance levels, and a flexible power sharing between the two involved power sources to cover the load demand, while the grid current presents a quasi-sinusoidal shape with a low total harmonic distortion coefficient (THD) coefficient.