Electrical
About the Electrical Team
The electrical team is tasked with getting the energy from the sun down to the tires. That’s quite an undertaking, and it poses quite a few challenges. The electrical team is broken down into several subteams to divide and conquer.
Projects
Power Distribution
Driver Controls System
Software
Solar Array
Maximum Powerpoint Tracker
Motor Controller
Telemetry and Infotainment
Driver Controls System
The car has more functionality than just driving. It has switches, buttons, lighting, a horn and more. The Driver Controls System encomposes such features.
Power Distribution
The car’s major electrical systems run at 120 volts. Managing this power and ensuring safety during operation is the responsibility of the power distribution team
Software
Logic and communication amongst the different electrical systems is done using embedded microcontrollers and a CAN bus, much like the average car. The software team programs these systems to specification, as well as creating dashboards to display the data created by these systems.
Solar Array
The solar array is the main provider of power for our vehicle. The array generates electricity from photons emitted by the sun as a limitless, clean source of energy.
Maximum Powerpoint Tracker
To get the Maximum Power out of our solar cells we are purchasing two Maximum Power Point Trackers to split the array in half. The input voltage from the array is going to be ~81V per MPPT and step up the voltage to battery voltage of 133V
Motor Controller
For Motor we have gone with the Marand SCM01 Permanent Magnet Motor. The Marand Motor is a 1.8KW motor with a nominal efficiency of 98.3% and has a maximum speed of 70mph. We plan to run two of these motors on the back wheels. Our Voltage rating is 150v and we will be running it at the battery pack voltage of 133v with a max current draw of 80A.
Telemetry and Infotainment
This subteam allows us to view all data that is relevant to the car. There are two different systems to collect and display data. The data is managed through three different CAN buses that are connected the boards in the car. Telemetry and Infotainment is run on a Raspberry Pi 4 equipped which uploads the data to a cloud web server using a router equipped with a SIM card. The server displays the data using either a condensed display for critical driver information or an in depth display for team members in the pit or chase cars.
Battery Pack
The battery is the hub that smooths out the performance of the car’s electrical systems. Our lithium ion battery pack can hold up to 4.9 kWh of energy that is used to power the car when the more power is needed than the solar panels are providing, or save excess energy when production is higher than consumption.
Battery Management System
The Battery Management System Team (BMS) is responsible for monitoring the battery pack during periods of charging and discharging. Any errors detected by the BMS are then sent to the rest of the vehicle via CAN, and the car will be shut down in order for the team to diagnose and fix said error. The BMS is also used in conjunction with an Elcon Charger in order to enable Level 2 charging at standard electric vehicle charging stations.
Battery Protection System
The battery protection system isolates the high voltage battery pack. Any voltage provided by the battery pack to other systems first goes through the BPS before going to other systems of the car. This system is comprised of a custom PCB which controls four high voltage contactors and has CAN communication to relay battery faults. The PCB will include a Teensy 4.1 microcontroller.