Control Unit
The control unit will integrate SAE J1772 Functions, Metering, Overload monitoring and will manage HMI and all
local monitoring.
• The SAE J1772 functions include the following:
• Energization and De-energization of the system
• Verification of vehicle connection; the EVSE de-energizes output when the connector is uncoupled
• Continuous monitoring of ground connection between the EV and the EV Charging Station
• Automatic De-energization of the cable in case of rupture or separation of the cable
• Continuous monitoring of EVSE current capacity with supply rating recognition by PWM 1kHZ signal
• Determination of ventilation requirements depending on battery type of vehicle
The GE EV Charging Station provides communications through the controller prompting proper cord management.
A message on the VFD screen instructs the operator to return the plug to the EVSE inlet, thereby reducing the
possibility of plug and cord damage. The proximity detection feature, which is part of the SAE J1772 connector,
enables the coupler to communicate the presence of the connector when it is inserted into the EVSE coupler.
Overload monitoring is provided by the control unit which features protection above 125% nominal current. This
threshold limit will be below the breaker protecting the EVSE’s limit to avoid local maintenance of the system during an
overload event. The control unit will include a 15-20 mA ground fault protection according to UL2231. An integrated
single phase meter will measure current and voltage in addition to calculating energy and power. The control unit also
performs monitoring of the contactor to ensure the contactor is in the correct state when charging or not charging.
User Interface
The GE EV Charging Station offers a user interface that is easy to operate and guides a user through charging their
vehicle. A Vacuum Fluorescent Display (VFD) screen features greetings, instructions, and charging station messages
as well as featuring communications for the single phase metering. The LED light located at the top of the charging
station displays charger statuses as follows:
• Green = Station active
• Blinking green = Vehicle connected, not charging
• Amber = Charging
• Red = Fault occurred
Radio Frequency Identification
GE EV Charging Stations offer the option for Radio Frequency Identification (RFID). The ISO 15693 compliant RFID
can be used with key cards provided by GE. Users will simply wave their key cards in front of the RFID reader at
the particular EV Charging Station intended for use and will be authorized to start charging. There are a few
benefits associated with implementing RFID:
• Ethernet network offered for RFID authorization service
• Provides security, enabling only authorized users to operate the charging station through RFID
• Secure software application offering different privilege levels for owner/operator of the EV Charging Station
RFID Software Application
The RFID software application is responsible for maintaining and processing authorization of users for the EV Charging
Stations it supports. EVSE operators will be able to control adding, removing, or suspending user authorization. The
software application also supplies reports on the EVSE usage, enabling data collection, and monitors the status of
communication between the RFID software and EV Charging Station. This is a local desktop application which runs
on a Windows
®
operating system, requiring Windows XP or Windows 7. The software desktop application, which
stores data in a relational database, communicates with the EV Charging Station controller over TCP/IP protocol.
