A Novel Torsional Excitation Scheme for Determining Mechanical Transfer Function and Natural Frequencies of Circumferential Vibration in PM Brushless Machine Drives

This paper presents a novel method, which utilizes the cogging torque as excitation, to determine the mechanical resonances and transfer function of a PM brushless drive for circumferential vibration analysis. By driving the prototype machine at various speeds using an in-line servo drive and measuring the cogging torque induced vibration response at each operating speed using a circumferentially placed accelerometer, the transfer function of the prototype drive can be obtained. The effectiveness of the proposed method has been confirmed experimentally.