Torque Ripple Suppression Control Based on the Periodic Disturbance Observer with a Complex Vector Representation for Permanent Magnet Synchronous Motors

This paper introduces a method for torque ripple suppression control involving the use of the periodic disturbance observer. By using the Fourier transform (or rotating coordinate transform and a low-pass filter), the torque ripple component, which is synchronized with the motor rotation, can easily be obtained owing to its periodic variations. With the new control method, a suppression control system synchronized with the torque ripple frequency can be built. Further, by using the system identification technique, the model system from compensating current value to torque detection value can be expressed as a speed-adjustable one-dimension complex vector in rotating coordinates. This method is suitable for an adjustable-speed drive, and the control parameters and reference model can be adjusted automatically. The most important feature of this method is its excellent performance for mechanical resonance suppression caused by torque ripple. This paper presents analysis and experimental results that validate the method.