Study On Control Method Of No Position Sensor For Brushless DC Motor Based On DSP

With the development of semiconductor electronic technology,there has been a new electromechanical integration BLDCM(BLDCM-Brushless Direct Current Motor).BLDCM combines the current power electronic control technology,control theory and motor control technology and other three types of technology.It has excellent speed performance: good control performance,wide speed range,starting torque and so on.Its application is very wide.BLDCM is divided into location BLDCM and locationless BLDCM.No position BLDCM has a number of advantages over location BLDCM: saving cost,reducing the size of the motor,and broadening the scope of application of BLDCM.In this paper,the basic structure of BLDCM and its working principle are studied,and the mathematical model and its transfer function are constructed.Then the control principle and method of positionless BLDCM are studied.In this paper,we study the zero-crossing detection method of the back-EMF,and find that the traditional zero-crossing detection circuit obtains the interference of the zero-crossing signal.On this basis,this paper presents a method to detect the zero-crossing of the back electromotive force.Then,Simulink simulation is carried out on MATLAB,and the test and analysis are carried out to verify the feasibility and reliability of this method.Then the hardware platform was designed.This article hardware control system to TI's DSP model for the TMS320F28335 chip for the master chip.Then in the DSP integrated development environment CCS6.0(2000)under the software design,the main use of C language and modular programming mode for the preparation of procedures,debugging and so on.Finally,this paper provides the waveforms and results of the relevant experiments.According to the experimental results,BLDCM can start and run smoothly under the off detection method.