Design Of Brushless DC Motors Controller Based On LPC2148

Brushless DC motors(BLDCM) are not only owning the characteristic of simple structure、 perform reliably, low maintenance that AC motors having, but also owning the characteristic of high efficiency、speed regulation well and so on that DC motors having. And not limited by mechanical commutation,it is easy to accomplish the large capacity and high speed designing. So BLDCM have broad application prospects in the fields of cars、robots、office automation and industrial.Therefore, BLDCM are considered to be the most development and application prospect of electronic control motors in the 21st century.So this article had designed a brushless DC motors control system using the LPC2148 as core control chip made of phillips.First of all, the paper described the background of BLDCM developmenting and research significance, then introduced the structure and working principle of the brushless DC motors.On the basic of the basic laws of electromagnetic, establishing the mathematical model of BLDCM which is the foundation of establishing simulation model of BLDCM control system.The article studied the simulation system with open control of BLDCM and the simulation system with speed closed-loop control of BLDCM based on the Matlab/Simulink.Secondly,The article studied the problem of the zero-crossing of back electromotive force(EMF) hardware detecting circuits that make phase of zero-crossing of back EMF delay and its size calculating. Obtaining that the exsited calculating formula for detecting the size of delay angle inconformity with the circuits,so the author had deduced a new formula for calculating delay angle of zero-crossing back EMF, and built simulating circuits to detect the results by Multisim. The verification results showed that the right of the new deducing formula and the exsited formula is indeed not match with this circuits.Finally, the article had designed the hardware circuits and control softwares of the controller based on the simulation work, the author had drawn schematic diagram of circuits and made PCB using the Altium Designer. The system had included hall interface circuits and the zero-crossing of back EMF detecting circuits,so it can controlled by using position sensor or position sensorless methods.The article had written the control softwares using C language in KEIL4 compilling environment with modular thoughts.Then the article had debugged the hardwares and softwares.Experimental results showed that the control system can be running stablely, regulatting speed with large range,adjusting speed to be stability, and achiving the requirements of the designing.