Torque Ripple Suppression Of Permanent Magnet Brushless DC Motor Basedcan DTC And EID

Electric vehicles have responded positively to the development requirements of energy saving and emission reduction,and become the upsurge of the development of the automotive industry.Permanent magnet brushless DC motor has a wide development space in the field of electric vehicle because of its low noise,small size,low maintenance cost,high torque and high efficiency.Under the condition of stable operation and load disturbance,the permanent magnet brushless DC motor has the problem of torque ripple,which affects the working efficiency,service life and user experience comfort of the motor.To solve the problem of torque ripple in permanent magnet brushless DC motor,a direct torque controller is designed.Direct Torque Control has many advantages,such as simple control,fast response and strong robustness.It has been widely used in motor control,but its control effect still needs to be improved.Based on direct torque controller,stator resistance compensator is designed to improve the accuracy of flux observation.Integral separation PID speed controller is designed to eliminate the speed overshoot caused by accumulated integral error and refine the sector to improve the accuracy of flux angle judgment.To further improve the ability of DTC to suppress motor torque ripple,a Direct Torque Control(DTC)-Equivalent Input Disturbance(EID)composite controller is designed.Equivalent input disturbance control module compensates the uncertain disturbance in Direct Torque Control by combining state observer,low-pass filter and disturbance estimator,and reduces the influence of uncertain disturbance on system performance.The experimental results show that the composite controller shortens the time of load disturbance stabilization,improves the effect of torque ripple suppression,and provides feasibility for theoretical realization.In order to fully verify the ability of equivalent input disturbance to suppress unknown disturbance,a double closed-loop-equivalent input disturbance compound controller is built based on double closed-loop speed regulation system.The composite controller compensates the disturbance caused by unknown disturbance,effectively suppresses the slope ripple caused by back EMF in the start-up stage,and reduces the wave rate of the torque in stable operation.