Electric vehicle modelling for function testing of charging infrastructures using power hardware-in-the-loop simulations

Abstract

Based on a sustainable development scenario with a 30% Electric Vehicle (EV) market share by 2030 the International Energy Agency projects a rise of grid challenges. In parallel, Electric Vehicle Supply Equipment (EVSE) is evolving to answer these growing needs. Efforts toward its standardization and association with smart charging strategies are being made to support grid integration while minimizing costs. Still, specific testing of EVSE technologies has yet to be established. Here, we model the digital twin of an EV and build a comprehensive Power Hardware-In-the-Loop (PHIL) test bench. Used for EVSE conformity validation, this testing setup contributes as well to grid stability evaluation. First, we developed an EV model enabling uni- and bi-directional scenarios. Then, we built a comprehensive PHIL setup integrating our EV model, a 22kW charging unit with a Type-2 connector, and a load emulator. Using this setup, automated procedures are established to test the charging station functionalities. Communication protocol and main mechanisms, such as defined in IEC 61851-1, are evaluated based on proposed key performance indicators. Furthermore, grid integration simulation is carried out to benchmark EV charging control strategies using a low voltage grid with representative loads as well as sources such as household loads, Photovoltaics (PV), and EVs. Regulating local bus voltages, control schemes with different access levels to grid status are designed and evaluated. We found that increased information access leads to reduced voltage deviations at the buses as well as improved power loss mitigation.