Brushless dc motor controller with dc motor adjustment and good starting performance advantage of the asynchronous motor has simple structure and no maintenance, thus the high reliability of motor speed regulation system controller. Motor controller is the controller is the normal operation of brushless dc motor controller and realizing the function of various speed servo command center, it mainly completed the following functions: for all kinds of input signals, logic synthesis for driver circuit to provide all kinds of control signals: to produce PWM pulse width modulation signal, speed adjustment to realize motor controller: the motor controller which can adjust the speed loop and current loop; The system has good dynamic and static performance; Short circuit protection, over current protection, under-voltage protection fault protection function. Controller is the electric bike driving system, it is the brain of a electric bike, its main effect is on the premise of guarantee the normal work of the electric bicycle, improve the efficiency of the motor controller and the battery, save energy and protect the motor controller and battery, and lower electric bicycle in the damage degree of damage. Brushless dc motor controller plays a key role in electric bicycles, thus to improve the quality and life of electric bicycle controller to start the first point is from the electric motor. So the biggest potential danger is the electric motor controller short circuit and over current these two problems. So to ensure the quality of the service life of electric bicycle and it has to brushless dc motor for electric bicycle controller for over-current protection design. For brushless dc motor controller for over-current protection can use price advantages, convenient installation of self recovery fuse for overcurrent protection of motor. Since the recovery after the fuse to protect the motor protective auto reply, installation is convenient, price concessions and other reasons. Comprehensive variety of advantages to use the restore the fuse for the protection of motor controller is the best choice.