A Novel Maximum Power Point Tracking Strategy for Stand-alone Solar Pumping Systems

A novel hybrid maximum power point tracking (MPPT) control strategy for stand-alone solar pumping systems without backup batteries is proposed in this paper. The whole control process consists of two steps: the judgment of speed up or down and the selection of step size of speed command. Basically, the system with the proposed MPPT strategy is controlled by a normal constant voltage method, while the reference voltage is periodically updated by a new multi-criterion method. In order to compare the control characteristics of different methods, two identical solar pumping systems are implemented. Experimental results show that the proposed control strategy is much better for stand-alone solar pumping systems