Sliding mode control of SEPIC converter based photovoltaic system

Abstract

Photovoltaic (PV) energy can be considered to be as highly efficient energy source since it is ecofriendly, harmless and available endlessly. In order to improve the output power of photovoltaic cells, the maximum power point tracking technology is used in PV systems. This paper designs a sliding mode controller based on SEPIC converter to implement MPPT. The difference from other methods is that the proposed method uses the circuit output voltage U 0 in the closed-loop system, so that the controller has better control effect. The buck-boost feature of the SEPIC widens the applicable PV voltage and thus increases the adopted PV module flexibility. First, the photovoltaic array is modeled and the simulation results are analyzed in this paper. Then model and analyze the SEPIC circuit and derive a sliding mode control strategy based on this circuit. Finally, the results obtained in MATLAB/Simulink were compared with the conventional P&O algorithm and INC algorithm. The results show that the sliding mode controller proposed in this paper has faster speed and less oscillation when tracking the maximum power point (MPP).