Highly-Scalable Differential Power Processing Architecture for On-Vehicle Photovoltaics

Abstract

On-vehicle integration of photovoltaics can extend the range of electric vehicles by a useful amount each day. However, partial shading can significantly limit PV power production even in stationary installations, and this is expected to be more severe in vehicles. Differential power processing (DPP) approaches can maximize PV output power despite partial shading. This work presents a PV-to-isolated-bus DPP architecture specifically for electric vehicle integration and a converter module that is designed to be extensible and inexpensive. The proposed architecture uses the vehicle’s existing low voltage battery as the common bus for the DPP modules and reuses the existing onboard charger to interface the solar string to the high-voltage battery. The proposed converter module achieves maximum power point tracking (MPPT) for the cell(s) it is connected to without requiring any communication or power transfer across the isolation barrier while allowing bidirectional power with synchronous rectification. The proposed architecture offers an inexpensive solution with high system efficiency and simple control that scales easily to large numbers of DPP units. The paper will include modeling of the advantages of the architecture, experimental characterization of the proposed DPP module, and experimental demonstration in a multi-cell, multi-DPP system.