Design of a single-switch DC-DC converter for PV-battery powered pump system

A single-switch non-isolated DC-DC converter for a PV-battery powered pump system is proposed in this paper. The converter is formed by combining a buck converter with a buck-boost converter. This integration also resulted in reduced repeated power processing, hence improving the conversion efficiency. The converter is able to perform maximum power point tracking, and battery charging and to drive the pump, on the condition that the pump can be operated without precise speed requirements. The battery in the converter provides a more steady DC-link voltage as compared to that of a conventional single-stage converter. Experimental results of a 14W laboratory prototype converter confirmed the performance of the proposed converter when used in a PV-battery-pump system.