High Voltage

Division Overview 

The High Voltage division manages the electric powertrain of a Formula SAE EV vehicle. Its primary responsibility is to design, assemble, and maintain the accumulator (battery pack), HV wiring harness, motor controllers, inverters, and all associated safety systems. The division ensures compliance with Formula SAE Electric regulations while optimizing power delivery, thermal management, and safety systems. Members must combine knowledge of electrical engineering, thermal systems, and strict safety procedures, since working with high-voltage systems is inherently risky.  

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Components 

1. Accumulator 

• Provides high-voltage DC energy storage for the electric motors. 

• Segmented for safety, cooling, and modularity.

• Integrated with a Battery Management System (BMS).

2. High Voltage Harness  

• Transmits energy between the accumulator, inverter, and motor.

• Requires precise sizing, shielding, and insulation. 

• Designed for minimal resistance and safe rotation through the chassis.

3. Motor Controller

• Converts DC from the accumulator to AC for the motors.

• Manages torque delivery and regenerative braking.

• Generates heat that must be removed through cooling.  

4. Pre-charge Circuit and Isolation Relays 

• Gradually charges capacitors to prevent damaging current spikes. 

• Provide isolation between the accumulator and the rest of the HV system. 

• Essential for both functionality and safety compliance. 

5. Cooling System

• Removes heat from motors, inverters, and the accumulator. 

• Typically, liquid-cooled with pumps, radiators, and fans. 

• Prevents overheating, loss of efficiency, or system shutdown. 

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Software 

• Computer-Aided Designs (CAD): SolidWorks 

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Requirements 

• INGE 3016: Algorithms and Programming 

• FISI 3172: Physics II 

• INEL 3105: Circuits I 

• INEL 4201: Electronics I 

• Knowledge of SolidWorks and ANSYS 

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Division Knowledge Guide 

Firstly, every member must understand the difference between AC and DC. Direct Current flows continuously in one direction and is stored in the accumulator. Alternating Current (AC) changes direction periodically and is required by the electric motors. The motor controller acts as the bridge, converting DC from the accumulator into AC for the motors. In FSAE EV, any system above 60V is considered high voltage, which requires strict safety measures like insulated gloves, face shields, and lockout-tagout systems.  

Battery packs can be connected in series (to increase voltage) or in parallel (to increase capacity and runtime). Designing an HV harness requires attention to wire gauge, insulation thickness, shielding against interference, and secure routing. The Battery Management System (BMS) is critical for monitoring cell health, balancing charge, and ensuring safe pack operation. The precharge circuit protects the motor controller from sudden current spikes when the system is energized, while isolation relays provide safe disconnection when the car is off. 

Thermal management is another vital area. Unlike IC cars, where cooling handles combustion heat, EV cooling systems manage electronics and battery safety. Common issues include air bubbles trapped in coolant lines or water pump failures, both of which must be diagnosed and fixed quickly to prevent overheating.   

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