Research Of Brushless DC Motor's Control System

In today's society,more and more countries pay attention to the serious environmental pollution and the lack of non renewable energy.EV,as a new energy vehicle,has the advantages of energy saving and environmental protection,and it is in line with the trend of the times.With the continuous research and development of the EV in the motor control system,the advantages of the BLDCM are more and more favored by many manufacturers,and occupy an important position in the scientific research.Of course,how to effectively improve the overall performance of the system that has been a closely watched issue.This paper of the study of BLDCM control system compared to the conventional has high stability,strong anti-interference ability,and it can effectively overcome the problem which caused bycommutation torque fluctuation in the traditional system,has good application prospects.In order to make up for the requirement of BLDCM,this paper propose a control system program of BLDCM.BLDCM has the both advantages of DC motor and AC motor,such as being able to respond immediately to the scene;the structure is relatively simple what can reduce the occupation of the space.Therefore,it is widely used in the field of industrial control,but brushless motor is not so perfect,it also exist such as nonlinear problems,which can limit of its improvement in control precision.This paper through the established nonlinear mathematical model ofthis motor in ?-? coordinate system,usin-g the algorithm of UKF to observe the value of the stator flux online,and simultaneously estimate the position and speed of the rotor.Finally it combine with the direct torque control method to control the motor.The algorithm has high accuracy and robustness,can more accurate select the corresponding voltage space vector to achieve the direct control of the BLDCM.