A fast and robust maximum power point tracker for photovoltaic systems using variable structure control approach

This paper presents a fast and robust maximum power point tracking scheme for photovoltaic (PV) generators. The fast dynamics is achieved by a sliding mode-plus-PI controller with a new optimal switching surface based on P-I characteristics of PV panels. The proposed controller is able to reduce the output power fluctuations during steady-state behavior while the fast response and robustness merits of the sliding mode controller are preserved. In response to a sudden change in radiation and temperature, the validity and capability of the method are verified by a grid-tied two switch flyback solar micro inverter simulation results. This topology mitigates the problem of high-voltage transients at switch turn off which commonly exists in single switch flyback inverters.