Nonlinear Phenomena of Varying Load Resistance Buck-Boost DC-DC Converting Solar Cell System with Perturbation and Observation Method for MPPT

Abstract

Inexhaustible solar power is booming for carbon reduction in recent years. The current efficiency of solar power generation is still low. Therefore, improvement of the power generation efficiency will be the research objective to scientists all over the world. The maximum power point tracking (MPPT) is an effective way to improve efficiency. Existing maximum power point tracking methods are incremental conductance method, perturbation and observation method, voltage feedback method and so on. Perturbation and observation method has the simple, easy to understand and the most common structure. In this paper, the nonlinear phenomena of buck-boost DC-DC converting solar cell system with perturbation and observation method for MPPT, considering converter operation in continuous conduction mode (CCM) with inductor current by varying load resistance is studied. The system is from periodic steady-state into period-doubling bifurcation to the chaos of nonlinear phenomena. Firstly the solar cell maximum power tracking system and converter working principle are explained. Secondly, the construction of solar maximum power tracking with perturbation and observation method and buck-boost DC - DC converter equivalent circuit model, then mathematical model is derived, and simulated by MATLAB / SIMULINK software package. Through the time-domain waveforms, phase plane and bifurcation diagrams, to explore the changing of load resistance system from a periodic steady-state into the chaos of nonlinear phenomena, chaos evolution mechanism of the system is analyzed.