A New Variable Step Size Hysteresis Comparison P&O MPPT Method for PV System

Based on the analysis of output characteristics of photovoltaic(PV) cells, this paper proposes a new maximum power point tracking(MPPT)algorithm for photovoltaic power generation. The method calculates the step disturbance using the slope of different points on the P-U curve, and applies the hysteresis comparison method to determine the disturbance direction, which makes the system stable without oscillation and track the maximum power point quickly and accurately. The MPPT model of the photovoltaic system is established with Matlab/Simulink software. Simulation results show that, compared with the fixed step perturbation and observation method, this algorithm can significantly improve tracking speed and accuracy. Moreover, when the external environment suddenly changes, the system can still rapidly track to the MPP and effectively avoid the error problem in the process of tracking, therefore improves energy utilization of the photovoltaic power generation system.