| BLDCM has been widely used in industrial applications because this motor not only has the merit of the DC motor for high performance and easy control but also has the merit of the AC induction motor for simple structure,reliable operation and easy maintenance.Appling integrated brushless DC motor in the vehicle's fuel pump, which can increase fuel pump's life span and improve its performance,is a future tendency and has good economic benefits and market potential.On the basis of the summary for developments and applications of brushless DC motor control system,the thesis introduces the structure and operational principle of BLDCM,then presents the mathematical models,and discusses the method of BLDCM rotor position detection which tests the Back-EMF signal.After comparing several design plans,then determine the design schemes for the hardware, software and system structure for this system.In the next chapters,firstly elaborate the system mechanism;include fuel pump's structure and BLDCM's structure,and figure out the mechanical properties and operational parameter.Then,the hardware and software design of the digital control system is dissertated in detail.The controller of the hardware of the system is built by using the dsPIC30F4012 as the microprocessor.The design of detail circuit includes:the inverter,the Back-EMF signal detection circuit,current detection circuit,drive circuit,the protection circuit and the layout of PCB.The software of the system includes:BLDCM's start-up program,the phase switching program and so on,the ADC serve program and the control of current and speed.Finally,the thesis presents the simulation model of a BLDCM control system by using MATLAB/SIMULNK.By the model,the electromagnetic torque,rotate speed and back electromotive force cures are presented.Also testify the validity of the brushless operation model and prove the rationality of the control system on the experimental BLDCM with the waveform in detail. |
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