Charge balancing PV System using charge-pumped flyback-boost-forward converter including differential power processor

This paper proposes a differential power processor using charge-pumped flyback-boost-forward converter including a function of charge balancing for PV System. This converter operates a boost converter and forward converter independently even with the transformer coupling. In the normal operation when the multiple loads have a power balancing, it has a high efficiency without the flyback operation. If the loads have imbalance among them, the charge-pumped flyback converter starts to operate for the output-capacitor charge balancing. This converter is cost-effective due to the unified transformer shared by the forward, boost and the flyback converters. Also, perspective of the MPPT efficiency, the forward converter operates as the differential power processor for the distributed MPPT control. Furthermore, since the forward converter is not fed by the boost output but by the coaxial coupled-inductor (transformer) of the boost, the power conversion efficiency is improved. An experimental verification from the 143-W hardware prototype is presented.