Convergence Analysis and Tuning of a Sliding-Mode Ripple-Correlation MPPT

The development of fast MPPT algorithms for photovoltaic (PV) systems with high bandwidth and predictable response to irradiation transients is attractive for mobile applications and installations under fast changing weather conditions. Among the existing techniques, here the focus is on a sliding-mode version of the ripple correlation MPPT (RC-MPPT). The paper proposes a dynamic model of RC-MPPT and gives a set of design guidelines for a proper tuning of the controller. The approach is based on sliding control theory, and includes modelling of chattering phenomena and effects of parasitic elements in the PV module. The analysis and design have been validated by both Matlab simulation and with experimental tests on a 35W panel with a boost converter charging a 24V battery. The results support the effectiveness of the proposed design guidelines and the expected transient response.