Optimal Charging Strategy for a Residential PEV Battery Considering Bidirectional Trade and Frequency Regulation

Abstract

A practical charging strategy for an individual plug-in electric vehicle (PEV) is proposed. A cost functionis constructed to reflect bidirectional electricity trade arising from surplus photovoltaic generation under the rewardsystem called feed-in tariffs and time-of-use electricity pricing. It is then extended to include the revenue forproviding vehicle-to-grid frequency regulation. In order to take advantages of high performance existing solvers,several mathematical techniques are applied to transform the discrete non-linear cost function to a differentiablecontinuous function. In the latter part of the paper, simulations are performed to verify and show the performanceof the developed model. A quantitatively developed battery wear model is also applied during the simulations tocalculate the effective operational cost, and to compare the costs for different control strategies. From the result ofcase study, the economic feasibility of the frequency regulation under the given circumstance is addressed as well.