Dynamis PRC – The 2022 Season

Report Eurocircuits

2022 marked the debut of the first driverless prototype of Dynamis PRC, capable of driving in both a manual mode and a full driverless mode, in which the car senses the environment, recreates a virtual track, calculates an optimal trajectory, and tries to follow it as best as it can.

In August, we competed in our first two driverless competitions in the Formula Student championship: FSEast in Hungary and FSG in Germany, where we ended up winning 2nd place in the driverless category of both races.

High Voltage Safety Boards

The high voltage system is the core of the tractive system of the vehicle, consisting of the four independent motors, the inverters to control the motors, the DCDC converter to provide power for the low-voltage system, and the battery pack itself.

Since there is high-voltage inside the car, there are numerous safety measures that need to be implemented.

Two of them are the Precharge circuit inside of the battery pack and the voltage sensing circuit inside the inverter, both of which are realised on board produced by Eurocircuits.

Precharge Board

Inverters always have a bank of capacitors on their input to smooth out the current peaks and to avoid strong current pulses to be absorbed by the battery pack. This means that a sudden connection of the high-voltage battery pack output terminals to the inverter would result in a huge inrush current that would damage components. To avoid that, the precharge circuit is used to slowly charge the inverters’ capacitors using a large resistor, and then it gets disconnected when the main isolation relays are closed.

Our precharge board includes the precharge relay, the precharge resistor, and a sensing circuit to verify the actual mechanical state of the relay.

Inverter Voltage Sensing Board

In case of a failure of the high-voltage wiring harness, the voltage on the inverters’ capacitor and the one inside the battery pack after the isolation relays may differ.

Therefore, we are required to measure the voltage at both ends to assure system integrity. The board inside the inverter enclosure also directly influences the status of the TSAL (Tractive System Active Light). In fact, the red light of the TSAL must blink red if the voltage inside the car is higher than 60V.