Auxiliary frequency and voltage regulation in microgrid via intelligent electric vehicle charging

The recently developed power electronic devices allow the flexibility of power and/or reactive power generation or consumption via electric vehicle charging. It is envisioned that a fleet of electric vehicles may provide auxiliary means for frequency and voltage regulation to improve the power quality and the stability of the power grid. This emerging technology is especially important for microgrid because of the volatility of power generation and consumption in a microgrid due to its diverse and sometimes unpredictable power sources and distributed load. In this work, the intelligent electric vehicle charging control for reduced cost and improved stability of microgrid is formulated as a constrained optimization problem. In order to capture the uncertainties in a microgrid, a discrete-time Markov Decision Process is adopted to model the dynamics of the system. Value iteration and policy iteration are used to solve the problem, and simulation results indicate that the resulted action policy made state transitions towards the stable states, thus scheduled electric vehicle to provide auxiliary regulation services to stabilize the system.