1. Formula Electric Vehicle Project ECE 492 – Spring 2019
Grounded Low Voltage (GLV)
Overview
GLV Break Out Board (BOB)
Safety Loop
The GLV System contains four main subsystems:
GLV Power -24V provided to all subsystems
Safety Loop - Closes AIR’s to energize high voltage system
Break Out Board (BOB)- Safety loop routing and relays.
Vehicle User Interface - Hardware for user interface with the vehicle.
The BOB encompasses most of the routing for the safety loop, and it provides data to the Raspberry Pi (VSCADA) through CAN, and I2C. CAN is routed to VSCADA through the GLV PCB so that TSV, Cooling, and TSI can relay information to VSCADA. On board chips communicate through I2C to relay the voltage and current of the GLV battery as well as the temperature of the PCB to VSCADA. These each will be displayed on the VSCADA display. There is a 24V to 5V DC/DC converter used to power the Raspberry Pi as well. There is a 5V relay on the BOB which allows VSCADA to trip the safety loop, and there are additional 24V relays allowing the GLV system to trip the safety loop.
The GLV system includes a safety loop which was designed in accordance with the Formula Hybrid Rules. The safety loop is composed of two loops.
Safety loop 1: runs through the GLV master switch, then the right E-stop, then the left E-stop before providing power to the car subsystems. It then passes through the Insulation Monitoring Device (IMD), and Accumulator Management System (AMS) relays. When power is provided to the car subsystems, the GLV LED on the cockpit panel will turn on.
Safety Loop 2: is only powered when a jumper is placed between itself and the end of Safety loop 1. This loop then passes through the IMD to the Brake Over-travel. Once the Brake Over-travel closes the SCADA relay receives power. This relay when closed by the SCADA will then route power to the Master Reset. Once the Master Reset is pressed both of the Safety System OK(SSOK) Lamps should turn on as well as the Safe light in the cockpit. Only once the Cockpit BRB is closed and the Cockpit Reset Button has been pressed will the Tractive System Voltage (TSV) Master Switch receive power. Which when finally closed the AIRS will receive power. The AIRS+ Led in the cockpit will then light as should the Tractive System Active Light (TSAL).
GLV System Block Diagram
The following block diagram shows the high-level view of the GLV system.
Safety Loop Block Diagram
GLV Enclosure and Vehicle User Interface
References
Acknowledgement
Project Documentations available on our website.
We would like to thank the past Formula Electric Vehicle Project teams( ) for their invaluable work on GLV.
We would also like to extend our gratitude to the Electrical and Computer Engineering Department as well as the Engineering Division at Lafayette College for their continued support.