MPC-based control structure for high-power charging stations capable of providing ancillary services

Abstract

The adoption of more electric vehicles (EVs) is going to pose some challenges for the grid due to the increase in demand for high-power charging. These issues will get further exacerbated with energy production moving from synchronous machines towards renewable energy sources (RES) with low inertia. High-power charging stations will thus, play a vital role since they can cause large power peaks but can also provide flexibility, especially if equipped with other resources, e.g., a battery energy storage system (BESS) and local energy production. These resources could be used for load shifting and to provide ancillary services for the grid if managed correctly.This paper proposes a hierarchical control structure for operating a high-power charging station that can provide ancillary services. The control structure uses model predictive control (MPC) for economic management of the local resources while also controlling reactive and active power to improve the voltage quality. Additionally, a droop-based control is used to enable frequency support as an ancillary service. Finally, simulations show how the proposed control structure can improve the operation of the grid while simultaneously increasing the daily profits of the charging station by 20% compared to a rule-based control strategy and by over 35% when ancillary services also are provided.

Keywords

• Model predictive control
• Energy management system
• High-power charging
• Electrical vehicles
• Ancillary services