The Identification of Load-side Inertia for Magnetic Drive Trains

The paper presents an identification method based on adaptive frequency tracking for the realtime identification of load-side inertia of magnetic drive trains encompassing variable torsional stiffness. Firstly, through analyzing the transient response of motor-side speed it is shown that the response incorporates a ramp component and a damped sinusoidal signal with a frequency approximately equals to the resonant frequency. Subsequently, a second order bandpass filter is designed to remove the ramp component and combined with an adaptive notch filter (ANF) forms a fourth order ANF. With the resonant frequency identified by the ANF, the moment of load-side inertia is then estimated. Finally, a numerical implementation method based on automatically calculating the damping ratio along with bandwidth, gain, and sampling frequency, is presented, and an iterative identification procedure is provided to solve problems associated with the limited duration of oscillations existing in the step response. Results show that the proposed methodology identifies the moment of load-side inertia with an accuracy of 3.3%.