The photovoltaic (PV) array output characteristic curve in nonuniform shadow conditions has multi-local maximum power points. In this case

it is hard for a traditional maximum power point tracking (MPPT) method to find the global maximum power point but fall into the local maximum power point. To address this drawback

by virtue of the fast response

good robustness in nonlinear system control of sliding mode variable structure control (SMVSC) and the succinctness and high tracking efficiency of perturbation and observation (P&O) method

an algorithm that combines SMVSC and P&O method is proposed. It is used in PV array MPPT control in nonuniform shadow conditions to solve the problem of multi-peak optimization in partial shading. In order to verity the rationality of the algorithm

the experimental circuit of PV array under nonuniform shadow conditions is built. The experimental results show that compared with the traditional P&O method

the algorithm proposed is capable of fast tracking the global maximum power point to make the system work stably in the vicinity of the maximum power point

to reduce the fluctuations of output power

thus making full use of solar energy. This work is supported by National Natural Science Foundation of China (No. 61105063).