Coordinated Control of EV Charging stations for Grid Frequency Support

Abstract

With the advancement in battery technology and power electronic converters, there is a massive increase in the use of Electric Vehicles (EV). Huge penetration of power electronic devices into the grid reduces the rotational inertia of the power system and compromise on the frequency stability. In order to reduce frequency error and the Rate of Change of Frequency (ROCOF) in low inertia power system, inertia support needs to be provided. Various methods are employed to provide grid frequency support by regulating the power exchange between the grid and grid tied inverter. In case of EV integration, virtual inertia can be obtained from two sources: one from the energy stored in dc link capacitors of the grid tied VSC and the other from the battery charging points. Coordinated control from the VSC and EV charging ports provide frequency support to the grid on an event of disturbance. This paper proposes a coordinated droop control strategy to mitigate the frequency stability issues.