Dynamis PRC is the Formula Student Team of Politecnico di Milano. It is composed of more than 100 students who, every year, with dedication and passion design and build a prototype racing car. After years of sacrifice and hard work, the single-seater competes in one of the major competitions for open-wheel cars: Formula Student.The Racing Team allows students to apply the knowledge acquired during their studies and to cultivate important hard and soft skills that are fundamental in a working context, such as teamwork, management of pressure, time and human resources. After reaching the fourth place in the world ranking and being ranked as the first Italian Team in the Combustion category of the Formula Student championship in the 2019 season, the Team decided to design and build the first electric prototype. Starting from the 2022 season, an autonomous driving system will be added in order to compete also in the Driverless category.Since the beginning of the team, Dynamis PRC has been developing and building all the low voltage electronics that are implemented inside the vehicle. With the transition to the electric category we decided to start the internal development of the BMS system, that for this season is at its third generation.In order to keep up with the continuous process of innovation that distinguishes Dynamis PRC, each season we develop more and more complex boards, for example by improving the computational power of control units, increasing the number of sensors that we can acquire or improving the telemetry system.FLEX PCBFor the first time in our history, we decided to make flexible PCBs. The necessity was born from the need to realize connections between boards, in spaces where the encumbrance of normal cables was not possible.For this reason, we decided to experiment the maximum innovation in terms of PCB manufacturing technology, adopting flexible boards. This has allowed us to make connections impossible with normal cables and connectors, saving space, weight and increasing the reliability of the system. BSPD, TSAL and INDICATORS BoardAmong the boards we realize there are also safety boards required by rules.Among these we find the BSPD, a board that monitors a possible state of implausibility between the accelerator pedal and the brake pedal. If a condition occurs in which the braking system is active and meanwhile there is a request for active torque to the motors, the BSPD opens the shutdown circuit, shutting down the car.The TSAL (Tractive System Active Light) is the board that takes care of indicating the status of the high voltage system. When the vehicle is turned on, the TSAL must be green, but when the isolation relays of the battery pack are closed, powering the inverters, the TSAL must flash red to draw the attention of those around the vehicle.The INDICATORS Board is responsible to switch on and off the indicators LEDs that notify to the driver the vehicle state. It takes as inputs the signals coming from the battery pack, the inverters and the BMS and switches on green and red LEDs.DCDC ConverterTo power the whole Low Voltage System of the vehicle, we developed a board that takes in input the high voltage of the battery pack, and thanks to some DCDC converter modules, we have in output a stable and robust low voltage to power boards and sensors.This solution let us to decrease considerably the size of our low voltage battery, reducing space and weight, key parameters for reaching higher performances.
