Design And Implementation Of Dual-mode Brushless DC Motor Controller

Because of the rapid development of the economic,more and more people move to the city for employment and better life in 21 st century.Due to the urbanization, population of the city increases fastly.With the continuous expansion of the cities,an environmental,convenient and low cost daily travel tool is in badly needed.So,The market of E-bike should have been increased constantly in the past few years and the next few years.As the core of E-bike control unit,Brushless Direct Current Motor(BLDCM)controller for the E-bike factories increases.In the after-sale application makets,in order to meet the requirement of BLDCM repair which one or more hall damaged.The dual-mode BLDCM controller can be used to the BLDCMs either with hall or not,due to this characteristic it is favored by most users of E-bike.Firstly,in this paper we introduces the development of E-Bike,BLDCM and its controller.On the basis of the BLDCM control system composition,we analyze its dynamic and static performance,especially take an in-depth analysis on the method of phase change control for dual-mode and the starting method of the sensorless BLDCM.In consideration of the market on the BLDCM repair and cost down of the E-bike system,proposed dual-mode BLDCM controller design requirements.Then,base on the theoretical analysis,considering the specification and needs of the system,we propose the zero crossing detection of the back electromotive force(Back-EMF)and zero start-up control strategy for sensorless phase change control and start implementation.Due to the project needs and the cost target of the control system,we use the 8-bit digital control IC SH79F1611 of SINOWEALTH Electronic ltd.,as the main control chip.Detecte the rotor position of sensorless BLDCM by using zero crossing detection of Back-EMF.Because of the interference easily caused in building the phase-center in the zero crossing detection,the control IC may indentify the wrong rotor position and give incorrect control signals.So,we give a method to building the virtual center by software.This paper introduces the hardware and software design of the dual-mode BLDCM controller based on SH79F1611,and test the system to verify its all performance as well as the stability.Finally,this paper gives a design of 48 V dual-mode BLDCM control system based on SH79F1611.The application of this design can reduce the bus of E-bike,and cost down the BLDCM.The experimental result proved that this control system have several advantagies in practicability,economical,and reliability.It will be widely used in the E-bike factory and after-sale market.