Blue Devil Motorsports Formula Electric Team

Blue Devil Motorsports Racing Team EV

https://www.ltu.edu/formula-electric/

Blue Devil Motorsports is the Formula Electric racing team of Lawrence Technological University located in Southfield Michigan, the team's goal is to manufacture a formula electric car from scratch every academic year which will participate at the International Formula Hybrid competition hosted in New Hampshire. Every year the team consists of about 30 members, it is a mix of mechanical, electrical and software engineering students. The formula electric program was started in 2018 and our team placed 3rd last year at the International Formula Hybrid competition. Our teams motto is to create a safe, reliable and fast formula electric car based on hard work, experience and team work.

Team's PCB Designs

All our PCB's are designed in house by the electrical and software engineering students in Altium. Our PCB's are all designed and optimized based on competition rules and safety of the car and the driver.

TSAL

The TSAL PCB or the tractive system active light PCB is a board which blink__s a light mounted on the chassis for a frequency of 2 to 5 Hz when high voltage is active or the tractive system is turned on. High Voltage is considered anything above 60 Volts. So, the TSAL board powers a green light for anything under 60 volts steady, and has to blink__ a red light for anything above 60 Volts. The board works with the help of a voltage divider, amplifier and a optocoupler which resets a 555 timer every 2 to 5 Hz to drive the mosfet which blink__s the red light. This board is really important in terms of safety of the people working on the car and around it because it makes them aware that high voltage is turned on the car and tractive system is active.

TSAL PCB

Temp Sense

The Temp Sense PCB multiplexes through each battery thermistor module and compares the analog outputs with a microcontroller, ensuring the temperature never goes above 60C. This PCB is part of the Accumulator Monitoring System. This PCB also, sends the temperatures on the CAN Bus which helps us in reducing the max torque of the motor controller in order to reduce the temperature. It also maps the PWM signal for the fans which cool the accumulator. The board uses a STM32F103C8T6 as the control unit.

Temperature Sensing PCB

Precharge

The Precharge PCB uses an RC timer circuit, Pre-charge ensures the capacitors in the motor controller are charged to 90% of their full voltage before closing the main contactors to prevent contact welding. This board is used for the safety of our inverter and the DC Links.

Precharge PCB

Relay

The relay PCB controls the shutdown circuit of the car. If any error state is detected on the car such as Temp Sense, CAN Bus, Brake Overtravel, Accumulator Monitoring System, BMS, IMD, Charging the relay PCB detects it and triggers the shutdown circuit which further disables high voltage and the tractive system.

Relay PCB

Vehicle Control Unit

The Vehicle Control Unit PCB takes an input from the throttle and maps it as a torque range and controls the motors torque using the CAN Bus. It also controls the ignition and ready to drive speaker, which is a speaker that buzzes for 2 seconds when the PWM on the motor is being enables. The control unit also sends pwm signals to radiator fans which cool the Motor and the Motor Controller. The VCU collects data from the BMS, Temp Sense and the Inverter and processes it to control different systems on the car based on mapping. The VCU is an integral part of the car because it controls the torque requests made to the motor. The microcontroller used by the VCU this year is a STM32F446RE with an onboard stlink.

Vehicle Control Unit PCB

Message to PCB Way

We decided to go with PCB Way because we have heard a lot about the good quality of the PCB and accurate tolerances which will help us make a better performing and safer car. We also like the wide variety of PCB specifications PCB Way provides this helps us customize our boards according to temperature grade and High Voltage standards which could make a difference on the cars weight. Some of the boards that we are really proud of this year are the TSAL, Temp Sense and the Vehicle Control Unit. We really hope this year we can build a higher performing car with PCBs provided by PCB Way.