Development Of Permanent Magnet Synchronous Motor Vector Driver For Electrical Bicycle

Nowadays, the electric vehicles are widely used in people’s daily travel with the increasing of people’s environment awareness, especially the electric bicycle, is becoming the first-choice of short-distance transport by consumers as it possesses clean, flexible, convenient, cheap, etc.At present, the main driving-motor of electric bicycles is brushless dc motors(BLDCM), which has trapezoidal EMF(Electromotive Force) and six-step square wave is applied for driving it. However, this control strategy has disadvantages such as torque ripples, noises due to the current fluctuations when commutation. In response to these defects, permanent magnet synchronous motors(PMSM) with sinusoidal back-EMF appeared on the market. The project here is to develop a PMSM vector driver for electric bicycles with the commission by company, and has successfully verified the applicability of vector control strategy on motor driver of electric bicycles through experimental platform and loading test. The main contents of this paper are as follows:(1)For controlling the speed, current, torque of the PMSM, vector control system of electric bicycle was established in id=0 mode based on its principle and mathematical model.(2)The STM32F103C8T6 based hardware circuit was designed which consists of power circuit, SCM and its peripheral circuit, main circuit, drive circuit and test circuit.(3)Software part of the motor driver was designed, and furthermore, corresponding solutions were given after making a analysis of the key technical problem, including initial position detection, rotor angle detection, real-time measurement of the motor speed and SVPWM over modulation.Experiment platform consist of prototype and motor driver is constructed based on hardware and software design, and related experimental waveforms are presented, which show the consistency with the vector control theory. In addition, the efficiency of motor driver is tested on the dynamometer, testing results show that the motor driver has high efficiency and large torque.Based on the above results, after two months of loading tests, the driver can operates stably, this verify the reliability further.