Research Of Electric Bicycle Brushless DC Motor Compatible Controller

Presently, in the market, the electric bicycle controller aims at a sensor or sensorless brushless DC motor and it leads to great inconvenience for the repair and replacement of electric bicycles. In this paper, it makes out a kind of compatible electric bike which can be controlled well by the brushless DC motor whether it has sensor or not.The controller can carry out all the functions of the single controller very well, it has lots of advantages such as good compatibility, high reliability and easy installation.To analyze the compatible brushless DC motor controller of electric bicycle ,the first ,it should research the performance of brushless DC motor .This paper gives a brief introduction to the structure, working principle and mathematical model of brushless DC motor, and it studies the controlling mode of the compatible brushless DC motor and whether it has sensor or not. Then it designs the hardware of compatible controller. the hardware section includes the main three-phase bridge inverter circuit and control circuit. The design of main circuit includes the choice of inverter control mode, the selection of MOSFET power tube and the study of protection circuit. control circuit uses the PIC16F72 microcontroller as the main chip which is produced by the Microchip, and the circuit design includes power circuit, detection circuit, speed given circuit, driver circuit, undervoltage protection circuit, overcurrent protection circuit and so on.to ensure the accuracy and response speed, it applies the PI control algorithm to the speed control and designes the speed control system for current-speed double closed-loop control mode.Finally, for the compatible controller, it designs software part and gives a detailed flowchart of the modules, and also controls the two experimental prototype separately.The experiment results shows that: the controller realized the control function better with the brushless DC motor with or without sensor,and the every indicator be showed normal,motor starting quickly, the speed tracking well and running smoothly and reliably.