Torque ripples due to positioning errors of Hall sensors and armature windings for PWM permanent magnent brushless dc motors

Despite of its remarkable active performances, brushless DC motors, which are widely used in mechanical engineering, have an obvious disadvantage in its high electromagnetic torque ripples. In the paper, a ripple suppression method based on predictive controls of stator currents is proposed according to analysis of causes electromagnetic torque ripples generate in commutation periods of brushless DC motors. First of all, a relative accurate prediction is acquired through DC motor on-line parameter corrections based on generalized predictive control algorithms. Then rolling optimizations make tracking errors and control qualities optimized for best control effects. And finally, minimum electromagnetic torque ripples are achieved. The simulation results show that torque ripples can be suppressed effectively with improved reliabilities by using the method proposed.

Download Full-text

An Adaptive Speed Control Approach for Sensorless Brushless DC Motors

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1070-1072.1202 ◽

2014 ◽

Vol 1070-1072 ◽

pp. 1202-1205

Author(s):

Fu Cheng Cao ◽

Ji Xia Shi

Keyword(s):

Brushless Dc Motor ◽

Bldc Motor ◽

Brushless Dc Motors ◽

Control Approach ◽

Brushless Dc ◽

Speed Controller ◽

Dc Motors ◽

Torque Ripples ◽

Model Reference Adaptive ◽

Novel Model

This research presents a new adaptive speed controller for the brushless DC motor. Themethodology of model reference adaptive control is applied to a novel model of BLDC motor. Thisnovel model provides the possibility to compensate the torque ripples and load torque.

Download Full-text

Battery Powered Lawn Mower

ECS Transactions ◽

10.1149/10501.0567ecst ◽

2021 ◽

Vol 105 (1) ◽

pp. 567-574

Author(s):

Pavel Vorel ◽

Jan Martiš

Keyword(s):

Permanent Magnets ◽

Operation Time ◽

Induced Voltage ◽

Brushless Dc Motors ◽

Brushless Dc ◽

Lawn Mower ◽

Dc Motors ◽

Practical Operation ◽

Battery Capacity ◽

Hall Sensors

An electric lawn mower supplied from batteries was designed and constructed. Li-ion cells are used because of their high volumetric and weight energy density. Falling prices of these batteries allow such a conception to be practical. Two separate motors are used – one for the traction and the other for the main blade drive. Both motors are brushless DC motors (three-phase synchronous motors with permanent magnets with a specific waveform of the induced voltage). Hall sensors are used to sense the rotor position which is necessary for the control of converters. A high torque outrunner construction of the blade motor was selected to eliminate the need of a gearbox. The used battery capacity of 1.6 kWh was shown to be unnecessarily high for a practical operation – a long operation time (more than 3 hours for one charge), high weight.

Download Full-text