UC Irvine

As fossil fuels continue to deplete, and emission standards become more strict, plug-in electric vehicles (PEVs) become more attractive. However, higher PEV penetration increases power demand on the grid, and immediate charging can induce large peak demands. A control algorithm, Continuously Varying Valley Filling (CVVF), is presented to enhance PEV charging at the local power level while minimizing the effects of uncontrolled PEV charging. Two decision mechanisms within CVVF are explored, crisp and fuzzy logic, to implement a centralized real-time valley-filling strategy that determines the preferred charging rate for vehicles to minimize distribution transformers damage. The algorithm assessed in this analysis reduces the highest peak and the average load during charging of 75 kW transformers by 15.80% and 13.75%, respectively