  Due to various green initiatives, renewable energy will be massively
incorporated into the future smart grid. However, the intermittency of the
renewables may result in power imbalance, thus adversely affecting the
stability of a power system. Frequency regulation may be used to maintain the
power balance at all times. As electric vehicles (EVs) become popular, they may
be connected to the grid to form a vehicle-to-grid (V2G) system. An aggregation
of EVs can be coordinated to provide frequency regulation services. However,
V2G is a dynamic system where the participating EVs come and go independently.
Thus it is not easy to estimate the regulation capacities for V2G. In a
preliminary study, we modeled an aggregation of EVs with a queueing network,
whose structure allows us to estimate the capacities for regulation-up and
regulation-down, separately. The estimated capacities from the V2G system can
be used for establishing a regulation contract between an aggregator and the
grid operator, and facilitating a new business model for V2G. In this paper, we
extend our previous development by designing a smart charging mechanism which
can adapt to given characteristics of the EVs and make the performance of the
actual system follow the analytical model.
