Introduction:

Our High Voltage (HV) system is a critical part of the car: driving the Low Voltage (LV) systems, to maintain the state of the car, and powering the motors, so that the vehicle can move! The figure below best summarizes the layout of the batteries, arrays, motor, and LV system and how they interact with each other.

Current HV Design (2023-2024):

Implementation:

1. At start up, the ignition sequence begins at Controls, (refer to the current implementation at Ignition Sequence) with the 12 V supplemental battery powering the LV systems.
2. BPS closes the "Contactor Control Signal" which complete the circuit and begin the process of charging the pre-charge contactors.
   1. BPS controls the Arrays Pre-charge Contactor.
   2. Controls manage the Motor Pre-charge Contactor.
   3. The two BPS "Contactor Control Signal" at the top is actually just one contactor, separated in the figure for diagram readability. BPS controls three contactors total.
3. The pre-charge contactors close after the positive and negative nodes at the terminals of these contactors indicate no potential difference (refer to how pre-charge contactors work in the "Software" section at Ignition Sequence). 
4. The LV systems are taken off the supplemental battery and connected to draw power from main 120 V battery, using the voltage that has been stepped-down with the DC-DC Convertor.
5. Now, during normal operation, the car can regularly alternate between charging and discharging states.

Misc:

1. The Motor Inverter is the motor controller that manages the PWM and regenerative braking functionality of the motor.
   1. There are four wheels on the car, but only one functional motor driving the car while the other wheels are freely rotating.
2. The Motor Discharge Button serve to remove excess charge built up on the motor, dissipating the power across the resistor in series.
3. The Maximum Power Point Tracking (MPPT) is implemented by Power Generation and boost the voltage from the arrays to match the voltage of the battery (refer to the current implementation at Sunscatter (MPPT).

Redesign considerations:

Refer to (2024-2026) PDR here: [WIP] HV System Redesign Considerations