Along with the vast market opportunities provided by EV charging infrastructure, significant challenges need to be addressed. One involves the lack of harmonized standards for key elements in a charging system, such as the charge cord, protection mechanism, power rating, plug type and coupler configuration, and communication. Such issues becomes more critical for fast charging systems than the ac slow charging method, since fast charging systems are often installed at public or semi-public areas and meant to be shared. Obviously, incompatible systems make sharing difficult.
The International Electrotechnical Commission (IEC) has created a set of standards to cover EV charging. For example, IEC 61851-1:2010 EV applies to on-board and off-board equipment for charging EVs at standard ac supply voltages up to 1000 V and dc voltages up to 1500 V. IEC 61851-23:2014 provides the requirements for dc EV charging stations. For its part, IEC 62196-3:2014 specifies requirements for EV charging couplers.6,7