The photovoltaic systems based on a sliding mode and adaptive controller

The output of photovoltaic (PV) systems is influenced by the environment. In this paper, a novel backstepping global fast terminal sliding mode (BGFTSM) algorithm is proposed to control the PV inverter through the duty ratio of the inverter. Backstepping control ensures the stability of the PV system by a Lyapunov candidate. The global fast terminal sliding mode control improves the convergence speed of the control system. The design of the BGFTSM controller achieves good dynamic performance. Additionally, a module of the transforming inverter duty ratio to the PWM signal is designed to make the inverter output the ideal waveform of voltage. Furthermore, a modified incremental conductance method of adaptive variable step size with saturated restrictions is used for maximum power point tracking (MPPT). The step size of the boost circuit duty ratio is chosen as the optimal gradient of the P-V function to track the maximum power point (MPP) fast. Finally, we perform simulation experiments of a PV system in the varying environmental conditions. Results confirm the effectiveness of the proposed solution.