Comparative analysis of differential power conversion architectures and controls for solar photovoltaics

Conventional solar photovoltaic (PV) energy conversion architectures are often forced to trade off efficiency and cost for increased power production. The differential power processing approach overcomes this limitation by enabling each PV element to operate at its maximum power point (MPP) while only processing a small fraction of the total power produced. This paper analyzes several differential energy conversion architectures and the associated local controls. Models are developed to describe operation of PV-to-PV and PV-to-bus differential converters. The overall power output of each system under various environmental conditions is compared. A Monte Carlo approach is used to compare three differential conversion implementations over a range of MPP conditions. Experimental results are included for a PV-to-PV, buck-boost differential converter to demonstrate the potential for increased energy production.