PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of brushless DC motor

Abstract

The invention discloses a PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of a brushless DC motor, which relates to a DC power supply, a brushless DC motor, a three-phase inverter bridge and a controller, and is characterized in that corresponding PWM measures are adopted to suppress commutation torque ripples through determining a rotating speed range and a commutation stage of the brushless DC motor, and the commutation time of the brushless DC motor is shortened at the same time; and the commutation time has greatly improvements on methods of position-sensorless control and back electromotive force zero-crossing point detection of the brushless DC motor, so that the smooth running performance of the brushless DC motor can be improved at the same time. Commutation torque ripples of the brushless DC motor in the whole speed range are effectively suppressed through selecting an optimal PWM mode in the commutation stage on the basis of PWM modes, the commutation time is shortened at the same time, the control is simple, the implementation is easy, and the smooth running performance of the brushless DC motor is improved. The method provided by the invention does not need to change a topological structure and can be used by slightly changing a software part, and the cost of a hardware system is not increased.

Description

technical field [0001] The invention belongs to the field of motor control, and specifically relates to a PWM modulation method for shortening commutation time and suppressing commutation torque fluctuations of brushless direct current motors, which is suitable for high-precision servo drive control of brushless direct current motors. Background technique [0002] Brushless DC motors are widely used in military, aerospace, office automation and other fields due to their small size, high power density, stable and reliable operation and other advantages. However, due to the inductance of the stator winding of the motor, large commutation torque fluctuations are generated during the commutation process, which brings problems such as vibration and noise, which limits its application in high-precision servo systems. [0003] The commutation torque fluctuation can reach 50% of the average torque. By controlling the current change rate of the on-phase and the off-phase to be equal ...

AI Technical Summary

Problems solved by technology

However, the commutation torque fluctuation suppression effect of this method is limited by the dynamic characteristics of the DC-DC converter. At the same time, more capacitors, inductors and power devices are introduced, which increases the cost of the hardware system and the complexity of the control system.

[0006] Existing commutation torque fluctuation suppression methods do not clearly explain the commutation time, nor do they point out specific strategies to shorten the commutation time

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