Flybak inverter is known as a low cost solution for photovoltaic ac module application. This paper presents a two-switch flyback inverter followed by a low frequency unfolding bridge for fractional horse power water pumping systems. This topology mitigates the problem of high-voltage transients at switch turn off which commonly exists in single switch flyback inverters. Moreover, the proposed control strategy achieves an integration of a novel sensorless MPPT algorithm and constant v/f control for the efficient utilization of both the PV panel and the motor. The proposed control algorithm minimizes the cost and simplifies the control strategy. The validity and capability of the proposed method are verified by both simulation and a DSP based two-switch flyback solar micro inverter practical results for a fractional horsepower water pumping system.

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