Direct Control of Plug-In Electric Vehicle Charging Load Using an In-House Developed Intermediate Control Unit

Unscheduled charging of a high number of plug-in electric vehicles (PEVs) can raise the peak electric load and affect the power quality (PQ) of the distribution power grids. This necessitates devising novel solutions to support the power grids when PEVs are being charged by controlling the PEVs' charging load. In this paper, an intermediate control unit for the commercial battery chargers is developed in-house, which can directly control the PEV charging load by modifying the power levels during ac charging. Furthermore, field measurements are conducted to investigate the impacts of mass-produced PEVs on the point of common coupling during charging by the developed unit with different power levels. In addition, a home charging management system that employs the developed unit is designed. The results from the field experiments, together with the model-based case studies, demonstrate that the developed unit can be readily adopted for direct control of the charging loads of mass-produced PEVs, without the modification of the existing recharging equipment. Moreover, in the context of charging management, the electricity cost can be minimized, whilst the preferences of the PEV owners can be realized and the PQ of the distribution networks can be maintained simultaneously.