Research And Development Of Brushless DC Motor Controller Based On Sensorless

With the development of power electronic technology, the brushless DC motor(BLDCM) control technology has become more and more mature and reliable, andBLDCM has been widely applied to many industrial fields. The BLDCM has theadvantages of simple control, and it has no mechanical commutation device. BLDC motorhas broad application prospects in the field of electric vehicle,servo control system andpower equipment of the underground work place. Because of this, we can believe thatBLDCM will be greater development in the related fields of kinetic energy in the future.Firstly the background, this thesis discusses the BLDCM of the development history,present situation and future development trend. Then, the thesis introduces the composingparts, basic operation principle, running characteristic and mathematical model ofBLDCM.Also thesis Particular introduces the working principle of the position sensor.Especially further analyze is made on the operational principle of the sensorless circuitbased on back-electromotive force(Back EMF) that is applied to this thesis.The main content of this thesis is to introduce a control system composed of sensorless,it can drive the underground exhaust equipment that need long time operation, andeffectively eliminate the gas explosion risk that caused by traditional DC motor ofmechanical commutation. Sensorless control technology makes the controller structure ismore compact, design is more simple and function is more powerful. According to theproject requirements and characteristics, the controller uses the Renesas MCU R8C/2L asthe main control chip. R8C/2L is the special chip for motor drive, and it is suitable to driveBLDCM. This MCU makes the whole control circuit more simple, system is more reliable,and programming more convenient. The hardware part of the control circuit are analyzedin detail according to its function. Software part adopts the way of modularization, andcompiles the main module flow chart. In the realization of some important functions,presents the basic method of program design.Finally, describes the fabrication and experimental of the BLDCM controller, and theobtained experimental data are analyzed. The experimental results show that the sensorlessBLDCM controller can operate normally,and the control principle of the motor is correct.