A Delay Control Method for Suppressing Torque Ripple of Brushless DC Motor

Abstract

The invention belongs to the field of the control of a brushless direct-current motor, and particularly relates to a delay control method for inhibiting torque ripple of a brushless direct-current motor. The method comprises the steps: detecting the circulation situation of each phase of current, and determining an off-phase, a conducting phase and a non-commutation phase subsequently needing the phase changing; enabling the off-phase to be maintained on in the delay time before the phase changing, maintaining the conducting phase off, and carrying out the pulse width modulation for the non-commutation phase; carrying out the phase changing after the delay is ended, turning off the off-phase, carrying out the flow-current by virtue of a diode connected to opposing bridge arms in parallel, enabling the conducting phase and the non-commutation phase to be normally switched on, enabling the time that the current of the off-phase is decreased to 0 to be equal to the time that the current of the conducting phase is increased to a stable value, inhibiting the current fluctuation of the non-commutation phase, and inhibiting the phase-changing torque ripple. A delay control time module is additionally arranged in an original control system, a formula for calculating the delay time is provided, the adverse effect caused by the trial-error delay time can be avoided, and the phase-changing torque ripple can be rapidly and effectively inhibited.

Description

technical field [0001] The invention belongs to the field of brushless direct current motor control, in particular to a delay control method for suppressing torque ripple of the brushless direct current motor. Background technique [0002] Brushless DC motors have the advantages of simple structure and large torque, and are widely used in various industries. They are considered to be the electronically controlled motors with the most development prospects and wide application prospects in the 21st century. However, there is torque ripple in the motor, which hinders its development to the field of high power and high precision. [0003] The control system of the brushless DC motor is a speed and current double closed-loop control system. The working principle of the system is: firstly, the speed given value is compared with the speed detection value, and the obtained speed difference is adjusted by PI (proportional and integral) through the speed controller. , the output is ...

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Problems solved by technology

[0004] However, there is inductance in the windings of brushless DC motors. During commutation, the drop rate of the off-phase current and the rise rate of the on-phase current are inconsistent, resulting in fluctuations in the non-commutation current, resulting in commutation torque ripple in the motor.

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