High-efficiency module-integrated photovoltaic power conditioning system

A module-integrated, photovoltaic (PV) power conditioning system with a high-efficiency, high step-up DC-DC converter is proposed. The step-up DC-DC converter employs an active-clamp circuit for soft switching of the power semiconductor switches. Also, a dual series-resonant rectifier is employed in order to remove the reverse-recovery problem of the output-rectifying diodes and to provide a much higher voltage conversion ratio. The PV current is estimated without using a DC current sensor, and the PV current ripple reduction technique is suggested to reduce the current ripple without an external component. A 1 kW prototype for the PV voltage range of 30-60 V is implemented, and all algorithms and controllers are implemented on a single-chip microcontroller. Experimental results show that the power efficiency is 92.5-94% and the ripple current is 3.5% of the rated input current.