Research And Design Of Fuzzy-PI Controller For Brushless DC Motor

The brushless DC motor(BLDCM)adots electronic commutation instead of mechanieal one,which overcomes a series of disadvantages of the traditional DC motor caused by the brush friction.It not only has DC motor's advantages such as high running efficiency,good speed regulation performance,but also has AC motor's series advantages such as simple structure,reliable operation,easy maintenance.The rotor of is excited by permanent magnet,without excitation loss.The appearance and development of high performance permanent magnetic materials,such as Nd Fe B,has greatly promoted the production and application of PMBLDCM.At present,many fields use PMBLDCM,including aerospace,military equipment,industrial automation,medical equipment,household appliances,electric vehicles,etc.Due to high running efficiency,wide range of speed regulation,high power density,large output torque,PMBLDCM is particularly suited as driving motor of electric vehicle.In this thesis,a fuzzy-PI control method based on the traditional PI control and fuzzy control is presented which is suitable BLDCM,this method overcomes the disadvantages of the traditional PI control method in the control of the permanent magnet brushless DC motor with the disadvantages of robustness and low accuracy.In permanent magnet brushless DC motor control strategy,fuzzy control is based on the idea of intelligent control,its biggest characteristic is does not depend on the model of the controlled object,but to use the formulated fuzzy control rules of inference to obtain the appropriate amount of control.The fuzzy PI control method is applied to the speed closed-loop of the permanent magnet brushless DC motor double closed-loop speed control system,and the fuzzy PI controller is designed in order to obtain better dynamic and static performance.Based on BLDCM's mathematical model,the simulation model of control system is build,and simulated in Matlab Environment.The simulation results indieate tha the Fuzzy-PI control system has fast dynamic response,small overshoot and excellent reliability.Finally,on the basis of the above theory and simulation,PMBLDCM controller based onDSP is designed,including hardware circuit design and software program design.After the establishment of the controller hardware platform,some certain experiment testing is done,and the expected results is achieved.Compared with classical PI controller,the arithmetic of Fuzzy-PI control to prove both the excellent static and dynamic performance.The entire system is evaluated in the end,and opinions on the existing problems of BLDCM's Fuzzy-PI control technique and further studies are put forward.