Study On Torque Ripple Suppression Technique For Permanent Magnet Brushless Dc Motor

Permanent magnet brushless dc motor has good mechanical properties and regulating characteristics, wide range of speed regulation, and great torque, simple structure, small volume, light weight and high efficiency and energy saving and a series of advantages, this a series of advantages make it widely used in transmission system and servo drive system. High performance of rare earth permanent magnetic material appears, with its excellent magnetic property and relatively low price, makes the permanent magnet synchronous motor development and research has became the focus of attention. But brushless dc motor torque ripple limits its in a wide range of motor speed, high precision of position and speed control in the application of the occasion. Due to the existence of motor stator armature inductance, commutation process will produce commutation torque ripple, and the commutation torque ripple is permanent magnet brushless dc motor torque ripple the main causes of the. Analysis and brushless dc motor in the process of commutation torque ripple become the focus of research both at home and abroad, in the light of brushless dc motor operation and control, problems existing in the study of a new control strategy, to suppress permanent magnet brushless dc motor commutation torque ripple.This paper first introduces the permanent magnet brushless dc motor control system the research status and development trend. The first permanent magnet brushless dc motor’s structure, and analyses the permanent magnet brushless dc motor of the operation principle and performance characteristics. Brushless dc motor to establish the mathematical model for the new control strategy to provide the theoretical basis for; Detailed analysis of the permanent magnet brushless dc motor commutation torque ripple reasons, it is concluded that the analytical expression of the torque ripple. For brushless dc motor drive mode, analysis of brushless dc motor the commonly used several kinds PWM modulation method for the influence of electromagnetic torque ripple. Both in domestic and abroad commutation torque ripple suppression technology on the basis of analysis, this paper proposes a new control strategy. Through the use of PWM modulation mode control three phase stator voltage, delayed turn off, make the turn off phase current smooth change. At the same time, through the control non commutation and conducting phase voltage and keep the commutation phase current constant, thus effectively inhibit the current commutation torque ripple caused by the process. To improve the control strategy was proposed based on digital signal processor (DSP) as the theoretical basis of brushless dc motor drive system design project; Completed the drive system controller hardware design, software design and system commissioning. Through the120°conduction type square-wave driving and improve the drive two different control under the way of comparative experiments show that the new method to control the commutation torque ripple and improve the brushless dc motor’s low speed running performance effectively.Experiments showed that the proposed permanent magnet brushless dc motor digital control strategy is correct and feasible, the control system hardware is simple, high reliability, the control system has good control effect. The paper work for permanent magnet brushless dc motor is widely applied to provide the certain theory reference and engineering practical method.