Frequency control of a microgrid including renewable resources with energy management of electric vehicles

The penetration level of renewable energy resources such as wind and photovoltaic in power systems is increasing. The intermittent nature of such resources introduces challenges for frequency and voltage regulation. On the other hand, with increasing the presence of EVs in the future grids and their charging/discharging management can provide ancillary services, such as frequency regulation to the microgrid. In this paper, a new strategy for charging or discharging of EVs in the presence of renewable resources is proposed. In this strategy, with the application of day-ahead load and generation of renewables, a cost signal is obtained to manage EVs charging and discharging process. Based on this cost signal, EVs are encouraged to discharge their stored energy while the microgrid power reserve is low and they charge when the power reserve is high. Moreover, four modes are defined in a way that EVs respond to frequency deviations in both charging and discharging processes. The results show that the proposed strategy in decreasing the frequency deviations and improving the power reserve of the microgrid is successful.