The Research And Design Of Sensorless Control Technology Of The BLDC Motor

Brushless DC motor (Brushless Direct Current Motor, BLDCM) because of itscompact structure, high efficiency and good controllability, increased its popularity inthe consumer and industrial electronic products, and brushless DC motor withoutposition sensor overcomes some disadvantages brought about by the position sensor,brushless DC motor in the industrial field obtained a better development, this articlefrom the two aspects of theory and practice of the brushless DC motor withoutposition sensor control technologies are studied.Firstly, this paper briefly described the background and application of BrushlessDC motor, analyzes the basic structure and working principle of Brushless DC motor,including the control method of Brushless DC motor is adopted in this paper--sixstep principle, principle of PWM pulse width modulation, BEMF zero-crossingdetection principle. And gives the mathematical model of Brushless DC motor, themechanical characteristic and transfer function.Secondly, this paper constructed without position sensor based onMatlab/simulink brushless DC motor control system simulation model, the simulationmodel is composed of various functional modules are independent, the functionmodules including PWM control module, control module, six step speed calculatingmodule and back-EMF module etc.. Matlab/simulink simulation to speed up thedesign and debugging process, shorten the debugging cycle, and laid the foundationfor the actual system debugging.Finally, this paper introduces the hardware and software design of controlsystem. Details of the main module and function of controller hardware circuit,software flow chart and the specific implementation, the controller is a simple test,and the test results are analyzed. At the end of the article, from the whole of thisproject are summarized, analyzed the problems encountered in the experiment, andmake prospects for the next step of work.