Research on novel maximum-power-point tracking for PV generation system

Because of the serious impact of ambient temperature and solar irradiance on photovoltaic(PV) systems, a novel controller with maximum power point tracking(MPPT) was developed, which could track environmental changes fast. The topological structure of a modified Buck converter which could sample the open circuit voltage and short circuit current conveniently was designed according to the detailed analysis of the basic principle of PV. An improved MPPT algorithm integrating the perturbation and observation method(P&O) and linear control was proposed based on small-signal model of PV system. The outer loop of PV controller is improved P&O algorithm for fast MPPT and the inner loop of PV controller regulates output current for stabilizing the output current and suppressing the load disturbance. The simulation and experimental results showed that the PV generation system has some good characteristics, such as good steady state, faster transient response, rapidly and accurately tracking the MPP changes, reducing the power oscillation around MPP and higher efficiency.