Optimum control strategy based on an equivalent sliding mode for solar systems with battery storage

Extracting the maximum power point (MPP) from the photovoltaic (PV) panel is very difficult due to its non linear I-V characteristic which is impacted by dynamic fluctuations in irradiance and temperature. This paper presents a modified equivalent sliding mode control (MESM), aiming to maximize the PV array output power. This method is applied to buck converter that is employed as interface between the PV generator and the battery to adjust the voltage levels and to track the maximum power from the PV array. To prove its (structure, converter, control algorithm) effectiveness, the proposed tracker is compared with the classical one (ESM) using the trapezoidal irradiance test as recommended by EN 50530. The results indicate that the proposed method can follow the MPP with best performance in static and dynamic states. In average, the performance of the proposed method is found to be slightly greater giving 99.60% efficiency compared to 97.99% in the conventional technique. Performance of the proposed technique has been tested through Matlab/Simulink™ simulations.