Electric Bicycle Controller Based On PSoC

The electric bicycles are popular more and more for their simple structure, portable, easy to maintain and other outstanding advantages, the market demand is growing. The control of Brushless DC motor (BLDCM) is the key technology for electric bicycles. Due to cost constraints, at present, many of BLDCM controllers are plagued with problems. The objectives of this study are to settle the key technical issues, and design a BLDCM controller for electric bicycles to meet the needs of low-cost, high reliability and complete function.Based on the structure and working principle of BLDCM, the voltage equations of BLDCM in conduction, freewheeling and commutation state are presented. After that, the torque characteristics and dynamic mathematical model of BLDCM are also introduced. On this basis, the thesis has made a profound analysis of electric bicycles'performance, and discussed the influencing factor of the electromagnetic torque.Programmable System on Chip (PSoC) CY8C24423 is used as the main controlling chip of the system, and the drive circuit is composed of discrete components, so the cost of the product is greatly reduced. This thesis also discusses the characteristics of the power MOSFET and its drive circuit. A method based on bootstrapping is used in the floating drive circuit for its low cost and easy to achieve. The detection circuits of BLDCM position signal and speed signal are described with PSoC hardware configuration method.In software part, according to the market demand, a program is presented. Based on the characteristics of PSoC, the functional modules and the main procedure structure of the control system are arranged. In the details, the electronic commutation, power monitoring and some other procedures are introduced.Finally, the motor with a rated voltage of 36V, rated power of 250W is selected as prototype to test the performance and functions of the controller, the graphics and data of the test results indicate that this controller can satisfy the needs of the market with low cost and good reliability.