Design and implementation of shutdown and indicator circuits for an electric formula student SAE type vehicle

• Κύριος συγγραφέας: Φουρτάκας, Νικόλαος
• Άλλοι συγγραφείς: Fourtakas, Nikolaos
• Γλώσσα: English
• Έκδοση: 2022
• Θέματα: Battery monitoring system; Electric vehicles; Formula student; Printed circuit board; Automotive; Safety; Battery cells; Ηλεκτρικά αυτοκίνητα; Μπαταρίες

In this thesis the design and development of a safety circuit for a Formula Student electric car is presented. The presented circuit consists of a plethora of subcircuits, each one taking into consideration accidents and mishandles of the vehicle with the only purpose of protecting and informing the driver and any human around, during such events. This “shutdown system” is designed taking under consideration the automotive standards. The system was installed in a Formula Student electric vehicle, a project supported by the Laboratory for Manufacturing Systems and Automation of the Department of Mechanical Engineering and Aeronautics of the University of Patras. Every subsystem follows the regulations of Formula Student competitions. In the following thesis, a quick review of the Formula Student competitions and history is presented, touching on the contribution of such institutions in the future of Automotive Engineering, and describing the procedure of a competition. This procedure (static and dynamic events), alongside the regulations that are centered around safety, are the guidelines of the design process. A compact review of the electric vehicle’s history is then presented, and the main principles of an electrical powertrain are mentioned. Following the above, the topology of the implemented shutdown system is presented. From the design to the installation of the circuit on the vehicle, the challenges and solutions to integration problems are presented. Next, each subsystem handling the safety functionality of the circuit is presented. Systems that monitor crashes, bad wire condition that may result in a short/open high voltage circuit, brake or acceleration pedal errors and many other crucial, for the integrity of the driver and the people around, are the cornerstone of this circuit. From the simplest to the more complex, all these systems are designed in a way that each error will be handled properly, and the driver will be aware of what the error was, using the appropriate indicators. Since the main purpose of the circuit is to protect people from the high voltage of the vehicle’s accumulator, that is delivered in all the sides of this four-wheel drive car, all the developed printed circuits follow strict guidelines since the co-existence of high and low voltage on the same PCB is needed. The way the shutdown system preserves galvanic isolation between the high and low power circuits is presented for each subsystem. Finally, thoughts on the possible improvements to the safety functionality and maintenance of the system are presented. The whole presented project was completed under the premises and guidance of the Laboratory for Manufacturing Systems and Automation of the Department of Mechanical Engineering and Aeronautics of the University of Patras.