Design And Implementation Of Synchro Gear Shifting Electric Bicycle Controller

As a new and popular vehicle, electric bicycle has been fast developing thanks to its convenience in both producing and using. However it's also bothered with problems such as low torque, low battery lifespan, motor demagnetization, and high controller fault rate, which could be major drawbacks to its further development. Gear shifting is proposed to improve the working condition of the motor. The study is a significant effort on improving the performance and developing a new driving mode for electric bicycles.First, large current is found key to the problems, and it is caused by the contradiction between speed and torque. A Gear box is designed allowing for both speed and torque. Possible problems in controlling the gear box and motor such as noise reduction, energy regeneration, synchronization prediction, and shifting strategy are studied, solutions of which are proposed through analyzing of the dynamic and static model of the BLDC motor.Second, mathematical models of the bicycle and road are built based on both calculation and experiment. A simulation is performed to prove the outstanding performance of the gear-shifting electric bicycles, as well as the effectiveness of the controlling algorithm.Finally, the BLDC motor driving and gear shifting actions are performed on an electric bicycle controller with ATMEGA48 MCU, which prove the whole design as feasible and effective.