The Electric Bicycle Control System Based On Brushless Motor Research And Design

With national energy gap and environmental pressure have increased recently, the issue of urban road congestion has also becoming more and more serious. Under this circumstances, electric bicycle is gradually turning to an important short traffic tool for the advantage of its convenience, save energy and environmental-friendliness. As a key part of electric bicycle, electric control system does matter a lot. And this very system’s stable and reliable operation relies heavily on the motor and its controller performance.Now it is known to all that the brushless DC motor is gradually making a figure in the market with its high-efficiency, low-noise, long-life and etc. This article aiming at the fact that the torque ripple and dynamic performance of brushless DC motor in electric bicycle, puts the directly torque control forward which improves electric bicycle controller to a certain extent.In the first part of this paper, structures and features of electrical controlling part in electric bicycle are analysed. Basic structure of brushless DC motor, mathematical model and its main controlling system are also included. Besides, it elaborate the characteristic of electric bicycle that torque mutates frequently when driving with load. The next part of this article introduces the concept of direct torque control, analyses the basic model of direct torque control and the effects of voltage space vector on flux linkage, then it researchs the theory, mathematical model and control system structure of how brushless DC motor operates with directly controlling torque. Furthermore, a direct torque control scheme on brushless DC motor in electric bicycle is presented. After that, simulation results improve that resolution proposed can effectively restrain the torque ripple of BLDCM and enhance the dynamic performance. At last, a hardware controlling system of electric bicycle which bases on brushless DC motor with dsPIC30f3010as its main control chip is designed. Specifically, it includes turning input circuit, current sampling circuit, rotor position detection circuit, driving circuit, Optical Coupling Isolation circuit and etc.