Enhanced differential power processor for PV systems: Resonant switched-capacitor gyrator converter with local MPPT

Abstract

This paper introduces an enhanced differential power processor topology and principle of operation for photovoltaic systems (PV) that is based on switched-capacitor technology, featuring local maximum power point tracking (MPPT) capability, zero current switching (ZCS), high efficiency over wide operation range, and reduced size. The new converter operates as a voltage-dependent current-source and is regulated by dead-time or frequency control. Local MPPT on the individual PV elements is realized and the operation is demonstrated by simulation and experiments. Differential power processing operation is verified on 100W prototypes, demonstrating ultimate improvement in the power harvesting capability of above 90% and up to 99% out of the available power in the string, under different insolation levels.