Research Of Brushless DC Motor Controller In Electric Vehicle Drives

As the increase of energy crisis and strengthen of the awareness of environmental protection, miniature electric vehicle which is environment-protective and energy-saving, has gradually accepted by people. Among all the miniature electric vehicles, brushless direct current motor is more welcomed by a large number of electric vehicle manufacturers for its excellent functions. However, BLDCM exists great torque ripple, which causes noise and vibration especially when the speed is not fast, and that even affects its driving performance. Before the battery technology make a great breakthrough, how to restrain the torque ripple and diminish noise while not raising the cost of hardware, has been an urgent problem for us to resolve. streamline low power BLDCM controller, accommodate it's branch out for the high power direction.The thesis begins with a brief analysis of BLDCM mathematical model, after which, constitute a more intuitive BLDCM emulation model with MATLAB/Simulink tool box, from which obtains emulation waveform. In that way, offer certain reference to the design of software and hardware of the control system. After searching and researching a large quantity literature, here extends a detailed analysis on the reason that how the phase change torque ripple produce. Simultaneously, analysed the toque ripple under different pulse width modulation, on the basis of not remarkably raise hardware cost, bring up a method of how to restrain the torque ripple of BLDCM used for miniature electric vehicle drive.In the aim of raise accuracy and safety of the controller, use photoelectric for the main technology, devised hardware of the controller system, and gived the hardware's circuit graph, among it including dsPIC30F2010 chip and it's periphery circuit, power-up circuit, photoelectric and power drive circuit, hall circuit and feedback detect circuit etc. exhausted the scheme realization of software, gives program flow chart of main procedure and part sub procedure.In the aim of prove theories analyse's accuracy and control method's feasibility, use oscillograph observed experiment waves of four kinds pulse width modulation and the control scheme this theories bought up, analysed experiment waves, attain objective and requisition of the devise, control sound effects, the devise have definite practical value.