Watkins-Johnson Converter Based PV Water Pumping System

A Watkins-Johnson (WJ) converter based photovoltaic water pumping (PVWP) system is proposed in this paper. WJ converter utilizes a tapped-inductor for storage and subsequent recovery of energy along with the ability to step-down without polarity inversion. Application of WJ converter in the PVWP system has an added advantage of achieving non-pulsating input and output currents, wider conversion ratio, higher stability, low stress on switches, and energy recovery functionality. The contribution of this work includes investigation of the WJ converter topology for PVWP application and implementation of synchronous control mode which improves the system performance. Test results verify that the performance of the system is unaffected by the variations in the environmental conditions and the system is able to maintain the required rated RPM without the requirement of any additional energy storage device.