Abstract: ABSTRACT： The traditional maximum power point tracking (MPPT) methods under even radiation condition usually have high efficiency. As the strong nonlinearity between photovoltaic (PV) array, irradiance and temperature, the traditional MPPT methods fall into local maximum under partially shaded conditions, which result in the failure of tracking the maximum power point. This paper established the PV array model under partially shaded conditions, and the voltage sweeping (VS) method was first used to get the voltage near the maximum power point by voltage sweeping comparison method, according to the multi-peak conditions caused by partially shade. Then the voltage value near the maximum power point was used as the initial value of variable step size incremental conductance method (INC) to finally locate the maximum power point. This method can avoid the maximum power point falling into local maximum under multi-peak conditions and effectively track the maximum power point under partially shaded conditions.

Key words: MPPT, partially shaded conditions, multi-peak, local maximum, voltage sweeping, incremental conductance method