Distributed control for large-scale plug-in electric vehicle charging with a consensus algorithm

As the development of plug-in-electric vehicles (PEVs) accelerates, the effective integration of large-scale PEVs with power grid becomes an urgent problem for utilities and PEV users. Mainly considering grid side preference, this paper proposes a distributed control method with a consensus algorithm to deal with large-scale PEV charging coordination. The objectives of the proposed coordination strategy are: minimizing the charging power loss and maximizing the available PEV power for vehicle-to-grid (V2G) services. The incremental cost functions are formulated for these objectives. The graph theory is applied to specify the communication network for PEVs. An interaction rule, the consensus algorithm is applied to realize the local information updating and external information exchanging among neighboring PEVs. A variable-size stochastic matrix is defined to specify the communication topology among PEVs, as well as guarantee the convergence of the consensus targets. The simulation results show that, with limited communication, the large-scale PEV charging/discharging can be efficiently coordinated to reduce total charging power loss or provide V2G service with maximum available PEV power. Meanwhile the PEV charging requirements specified by drivers can be satisfied. In addition, the convergence of the proposed distributed consensus algorithm can always be guaranteed upon random PEV departures.