Abstract:The control system consists of Brushless DC Motor,controlling part,sensor part,hardware and software controlling part. With its unique advantages of high efficiency, high reliability, good controllability and maintenance-free,it is widely used in many fields.To d evelop the electric-bike will be helpful to solve the pollution problem caused by the waste gas from the gasoline-automobiles and energy sources problems.
The task is to design a Brushless DC Motor (BLDCM) controls ystem For electric-bike.According to the project,PIC16F72MCU produced by Microchip Company has been selected.T he design of hardware including MCU circuit,logic lock circuit,position of the rotor circuit, power circuit, voltage up circuit, hardware protection circuit, electronic commutatorci rcuitan dd isplayc ircuith aveb eenc arriedo ut.Th erea reth reeh allse nsorsfor he position of the rotor, according to the position of the rotor and pwm (pulsewidth modulation)controlsi gnals,the electronicc ommutator works.
The software was designed following the principle of modularization and structured programming and using assembly as the programme languages.The display module is designed.Ty pical PI control strategy is used to control the speed.Mode identified module can identify the angle of the BLDCM, the position of the rotor and the output of the system automatically. Less voltage protection, current excessive protection and wrong angle protection are designed to reinforce th e system. Also,factors that affect the reliability of the system are discussed in this paper,and some m ethods are introduced soon after.
This controller realizes three work modes-electromotion,stationary speed and assisting work mode.Another self-test mode,which work sunder error,is also designed.This kind of brushless DC motor control system is superior in many fields such as high reliability, simple hardware st ructure,lowcost,and convenient for the further development.
Key Words: Electric bike; Brushless DC Motor; PIC; Control System