Research And Design Of Six Phase Asymmetrical Brushless DC Motor Controller

The operation principle of brushless DC motor is basically the same as that of brushless DC motor.Their rotors are all permanent magnets.The stator is made of multi-phase windings.The magnetic fields generated by the permanent magnet rotor and the windings on the stator are superimposed to drive the motor to rotate.Compared with the structure of brushless DC motor,the brushless DC motor cancels the electricity.Brush and commutator use power electronic devices to realize commutation function,so that the energy loss and equipment loss of motor in commutation process are smaller.Brushless DC motor has a wide range of applications in China,such as household appliances,national defense and aerospace,new energy electric vehicles and so on.Based on the above research background,this paper studies and analyses the control system of brushless DC motor,and applies a unique control strategy to control brushless DC motor.The system field has certain practical significance.In this paper,six-phase asymmetric brushless DC motor is taken as the research object,in which the components of the whole system and two sets of windings are driven by two or two-way-on mode.On this basis,this paper focuses on a new sensorless control strategy for BLDCM.On the basis of obtaining the initial position of the six-phase BLDCM,a new three-stage starting method is used.Then a program of frequency-rising and voltage-rising is set in the program to make the motor rotate continuously and drive the signal acquisition.With H_PWM-L_ON modulation mode,the motor speed continues to increase at this time.When the motor speed reaches 1700 r/min,the three-phase windings of R,S and T with large back EMF coefficient in the six-phase asymmetric motor are cut off,so that the motor continues to operate under the three-phase winding,so as to prevent the motor speed from increasing too fast and causing operation errors.Sixth part is studied.The problem of restraining the torque ripple of asymmetric motor is studied.Then the simulation model of position sensorless six-phase asymmetric brushless DC motor is built by PLECS simulation software,which verifies the feasibility and accuracy of the new control strategy studied in this paper,and proves theoretically for the physical construction.Finally,according to the theoretical analysis and simulation model,the experimental platform is built,and the hardware circuit of six-phase asymmetric brushless DC motor and the software program of DSP and CPLD are designed.After starting and stopping of the motor,acceleration and deceleration,and the shortcomings of the scheme are also analyzed.And the parts that need improvement point out the direction of other people’s research.