Research On The Control System Of Dual-mode Drive Brushless DC Motor

Brushless DC motors has quickly been widely used due to their high reliability,high power density and speed regulation characteristics similar to DC motors.However,the square wave control commonly used in brushless DC motors is inductive in the motor windings and the current cannot be changed abruptly,which directly leads to the generation of severe torque ripples and limits the application of brushless DC motors.Starting from the suppression of the torque ripple of the brushless DC motor,this paper conducts an in-depth analysis of the brushless DC motor control strategy,and studies a brushless DC motor control system using dualmode control.First of all,starting from the motor itself,this dissertation analyzes the basic structure and operating mechanism of the brushless DC motor,the principle and the principle and performance of the sine wave drive method and the square wave drive method commonly used in permanent magnet motor control.On this basis,a dualmode brushless DC motor control system is proposed.The sine wave drive is used to improve the running state of the motor in the low-speed area,and the square wave control is used to increase the system output torque in the high-speed area.At the same time,to reduce the square wave control in the high-speed area.It is proposed that the overlap commutation method is used to suppress the torque pulsation in the commutation area,and a control system with low torque pulsation in the full speed range that takes into account the characteristics of square wave drive and sine wave drive is obtained.Aiming at the problem that conventional Hall sensors cannot obtain accurate rotor position angle,a rotor position observer using fuzzy PID synchronous rotation filtering processing is proposed to obtain accurate rotor position.The simulink analysis is carried out by building a simulation model.The simulation results show that the rotor position observer has a good effect on the estimation of the rotor angle,and the dual-mode brushless DC motor control system has a smaller torque than the traditional square wave control.Pulsation: Compared with the traditional sine wave control,with a larger torque output,the dual-mode brushless DC motor control system can improve the performance of the brushless DC motor.Finally,with TMS320F28335 as the main control chip,an experimental platform of the brushless DC motor control system was built to verify the performance of the control system.The experimental results show that the dual-mode brushless DC motor control system has the characteristics of accurate angle estimation,fast response speed,good dynamic performance,smooth control method switching,and low output torque ripple in the full speed range,verify the rationality of the system design in this dissertation.