EVSE

Overview

An Electric Vehicle Supply Equipment (EVSE) delivers electricity via EVSE ports to charging inlets located on electric vehicles (EVs). An EVSE may also be referred to as a charging station, charge point, or an EV charger. The meaning of these names often vary and are subject to interpretation.

There are three commonly referred to Types of EVSE. EVSE are modeled in Project Haystack using the evse-assembly conjunct. See the chapter Modeling EVSE for more details.

Types of EVSE

Level 1 AC EVSE

Level 1 AC EVSE may deliver up to 2.5kW of AC power to the EV's charging inlet. The EV's onboard converter transforms the inputted AC power to DC power, which is used to recharge the EV's battery. This EVSE is only available within the North America market, adheres to the SAE J1772 Type 1 or NACS EV charging specifications, and requires a 1-phase, 120V electrical input from a standard wall outlet.

Level 2 AC EVSE

Similar to the Level 1 AC EVSE, Level 2 AC EVSE delivers AC power to the EV's charging inlet. However, the Level 2 AC EVSE is capable of delivering more AC power due to it's support for higher voltage, 1-phase, or 3-phase electrical inputs. Faster recharging times are possible as a result. This EVSE adheres to the SAE J1772 Type 1, SAE J1772 Type 2, NACS, or SAE J3078 EV charging specifications depending on the region in the world and use case.

Level 3 DC EVSE

Level 3 DC EVSE delivers DC power directly to the EV's charging inlet, eliminating the need for a converter onboard the EV. It is also referred to as a Direct Current Fast Charger (DCFC). In some cases, such as when an EV has a battery pack that is greater than 500VDC, there is still a DC to DC converter onboard the vehicle to allow recharging the EV using an earlier generation Level 3 DC EVSE that is not capable of delivering more than 500VDC output.

Typically Level 3 DC EVSE deliver more power and recharge EVs considerably faster than Level 1 or Level 2 AC EVSE. This is because they convert AC power to DC power with fewer space, weight, and cost constraints than converters designed to be onboard an EV. Level 3 DC EVSE adheres to the CCS1, CCS2, CHAdeMO, NACS, or MCS EV charging specifications depending on the region in the world and use case.

Tagging EVSE Types

It is often difficult to estimate how long it would take to recharge an EV when referencing these EVSE types for reasons including:

• The range of power that each EVSE type may deliver has increased
• Several available EVSE products may be considered a Level 2 AC and Level 3 DC type simultaneously
• These EVSE type definitions do not clearly convey what electrical input and output specifications apply to the EVSE
• Variety in the EV battery sizes

Presently Project Haystack does not describe EVSE types using standard tags. Instead the following approach is taken to convey important related metadata:

• Electrical input specifications for an evse-assembly are described using attributes
• Electrical output specifications for an evse-port are described using attributes
• An evse-port is described to deliver AC or DC power to an EV's charging inlet using the ac or dc tag, respectively
• An evse-port may only have the ac or dc tag, but not both

Modeling EVSE

EVSE Assembly

An EVSE Assembly is modeled with the evse-assembly tags. The below Figure shows the UML representation for evse-assembly:

An evse-assembly delivers electricity via EVSE ports to charging inlets located on EVs. It is a manufacturer produced, safety certified combination of hardware that has manufacturer provided technical specifications and instructions on how to be installed and operated. Also, it is comprised of one or more equipment enclosures and power fed from one or more branch circuits. Electrical input specifications for an evse-assembly are described using attributes.

EVSE Port

An EVSE port is modeled with the evse-port tags. An evse-port delivers electricity to a single EV charging inlet at a time. More than one evse-cable may be connected to a single evse-port, but only one may be energized at a time.

Electrical output specifications for an evse-port are described using attributes. An evse-port is described to deliver AC or DC power to an EV's charging inlet using the ac or dc tag, respectively. An evse-port may only have the ac or dc tag, but not both.

EVSE Cable

An EVSE cable is modeled with the evse-cable tags. An evse-cable models the electrical connection between an evse-port and an EV charging inlet. This electrical connection may be made via a physical charging cable, a pantograph, or an air medium for wireless EV charging.

Each available electrical connection between an evse-port and an EV charging inlet may be modeled using evse-cable. The type of the electrical connection will eventually be modeled as an attribute on evse-cable.

Future Work

The EV charging working group recently formed. The definitions presented should be considered preliminary and subject to change. We plan to add more definitions related to EV charging in the future. Specifically, future work will describe how to define attributes for evse-equip.

If you are interested in contributing to the EV charging working group, then please reach out to WG 982 on the Project Haystack forum here.