Metering Requirements and Design for an Electric Vehicle Charging System Providing Grid Services

Vehicle-to-Grid (V2G) technology is capable of providing grid services from electric vehicles (EVs). To do so, it imposes more demanding engineering design requirements on electric vehicle supply equipment (EVSE). To provide grid services, bidirectional power flow and accumulated energy between grid and EVs must be metered and uploaded to a remote server participating in electricity markets. Requirements, including accuracy and latency of power and energy data, are crucial parameters. In this article, an overview is provided of a built-in metering module, now designed and built into an EVSE charging station. Design decisions and performance include measurement approaches, communication to a higher-level module, and the standards that must be met.