Research On Dual-mode Field-weakening Control For Brushless DC Motor

Field-weakening control for brushless DC motor is one hot spot in such fields as research on control for brushless DC motor, especially when brushless DC motor is used as the drive motor in electric vehicle. Field-weakening control for brushless DC motor is also one difficult point, field-weakening control for brushless DC motor is far away from matured now.On basis of referring to lots of domestic and international literature, this paper rea-lized field-weakening control for brushless DC motor successfully by using dual-mode control based on new inverter.The paper discussed the back ground and significance of flux weakening control for brushless DC motor first.Then the paper introduced the basis of brushless DC motor, such as structure and principle of operation and mathematical mode of brushless DC motor.And then the paper discussed principle and simulation based on MATLAB of field-weakening control for brushless DC motor. The result of the simulation and analysis on field-weakening control demonstrated that phase advance method could realize field weakening, but the method would amplify the current in the motor greatly. Besides, the result demonstrated that field-weakening control for brushless DC motor using dual-mode control based on new inverter could not only get good field weaken-ing effect, but also overcome the shortage of current phase advance method.The paper also built the hardware and software system for the dual-mode control-ler.Then the experiments verified the field-weakening control for brushless DC motor.Finally, this paper summarized the performance of this topic and work needed be done in the following days.