Intelligent current control for brushless DC servo machines

Brushless DC motor has been used in many high performance mechatronics applications. This paper addresses the problem of minimizing the torque ripple of brushless DC motor, especially when the speed is low. Based on the analysis of the switch states and of the fixed frequency sampling PWM method, an intelligent current control method for brushless DC servo machines is proposed. The inverter can self-tune its sampling frequency according to the rotation speed of the motor. Not only can this method make the inverter work steadily at the expected frequency, but also it can minimize the torque ripple and improve the precision and the response speed of the current regulation. Experimental results are presented to demonstrate the practicality of the proposed current control method.