Abstract: PV array output power is a nonlinear function of the external environment and the load, in order to give full playing to the performance of photovoltaic array, maximum power point tracking (Maximum Power Point Tracking, referred to as MPPT) control adjust the disturbance of accounting space based on the work of photovoltaic arrays. Although the existing variable step size control has a better ability to fast tracking steady-state effect, but itís complex and less versatile. Contrary to the characteristics of the poor start up in the MPPT, Proposed a new maximum power point tracking (MPPT) control method, that mutations in the external environment or the load, the first fixed voltage method to adjust the operating point of PV array to the maximum power point nearby, to ensure fast tracking; on this basis, the introduction of small step perturbation and observation method of maximum power point to optimize the steady-state characteristics, which can effectively reduce the output power of photovoltaic array maximum power point in the oscillation. The simulation results of the fixed voltage method, perturbation and observation method and the combination of the two proposed methods show that the method can quickly and accurately track the PV array maximum power point, reduce the maximum power point oscillation energy loss and improve the conversion efficiency of the photovoltaic energy system.

Keywords: Photovoltaic array; maximum power point tracking; a fixed voltage method; disturbance observation; variable step.