Dual surface sliding mode controller for photovoltaic systems enhanced by a ripple domain search maximum power point tracking algorithm for fast changing environmental conditions

Abstract

In this research, a dual surface sliding mode controller is proposed and implemented to increase robustness and speed of boost converter, its asymptotic response is proved in the presence of disturbances. In addition, a filtered mapping pulse width modulation technique is developed to attenuate the chattering problem caused by finite frequency switching. Ripple domain search (RDS), a precise maximum power point tracking (MPPT) algorithm, is suggested to find the maximum power point (MPP) in photovoltaics. RDS uses the inherent ripple problem of the converter as a tool for finding MPP. By combining the proposed fast controller and the RDS algorithm, a fast and robust MPPT technique is obtained, which is simple to implement, eliminates the need for initial parameter tuning and is free from oscillations. Moreover, the proposed controlling method and MPPT algorithm are tested using Mitsubishi Electric MF170W module and their efficiency is compared with conventional methods (including P & O) in fast irradiation changing conditions. The proposed method harvests a 6% higher power than P & O and constant voltage. Compared with incremental conductance 24% more power is harvested. Finally, the practicality of the controller and algorithm was experimentally validated with a prototype system using a 5 W Evergreen module.