| Summary: | 碩士 === 國立中興大學 === 電機工程學系所 === 106 === Recently, electric vehicles (EVs) have become a new generation of transportation vehicles in many countries. Gasoline vehicles are gradually replaced by electric cars. However, the brake system is mainly traditional hydraulic auxiliary disc brake, and the braking system is independent with the driving system. This thesis proposes a system that can integrate driving and braking design in a compact module. We use the back electromotive force generated by the rotation of the motor as the braking energy, and then change the order of the inverter switches to generate the braking effect. The switches control the magnetic field of the motor so that the motor has a reverse resistance to achieve quickly braking. However, the braking force might be large to damage electric components of a large-powered electric vehicle. To resolve the problem, we uses the duty cycle of the pulse width modulation(PWM) effect to control the upper and lower arm switching mechanism. It adjusts the braking force in an efficient way. The system is equipped with an adjustable regulator to achieve braking control while avoiding surge voltage and surge current of the switching elements. We have successfully applied this design to an electric scooter and an electric car. We test engine braking and general braking, then compares the time of sliding and braking. Finally, we analyze the braking performance according to the braking time.
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