Improved low cost induction motor control for stand alone solar pumping

Control strategy for standalone solar pumping system based on induction motor and without DC/DC converter has been widely studied and discussed in the literature. This topology is of great concern due its economic issues, especially when a standard frequency converter (SFCs) with scalar control is used instead of a dedicated PV inverter. This paper proposes an external control module to generate SFCs frequency reference in order to ensure both maximum power point tracking (MPPT) and optimize IM power. It is a low cost solution since it requires no additional power equipment. Modeling and design of each system parts are performed to determine the analytic expression of frequency reference. The effectiveness of the proposed approach is illustrated by simulations carried out under PSIM Software, and validated through experimental investigations on a 1.5kW laboratory set-up.