An Enhanced Dynamic Simulation Model of a Hybrid Magnetic Bearing Taking Account of the Sensor Noise.

Dawid Wajnert,Jan K Sykulski,Bronislaw Tomczuk

doi:10.3390/s20041116

Dawid Wajnert, Jan K Sykulski + Show 1 more

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https://doi.org/10.3390/s20041116

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Abstract

The paper presents simulation and experimental verification of the hybrid magnetic bearing (HMB) performance characteristics. It has been demonstrated that the additional errors from the eddy current sensors have a significant impact on the control signals. An improved mathematical model combines a nonlinear magnetic equivalent circuit of the HMB with the ordinary differential equations of its transients. These equations describe the rotor motion and the electric circuit of the system, as well as the control system required for stable levitation of the rotor. Certain harmonics have been observed in the displacement signals of frequencies equal to the multiples of the cylinder rotations. The calculation model has, therefore, been improved, taking into account the interference of the harmonics. Simulation results were validated by comparing the time responses of the transients obtained from the numerical calculations with those measured on a real object; a satisfactory agreement between the results has been achieved.

Highlights

Investigations of transients in magnetic bearings require a computationally efficient simulation model that encompasses the control system
Contemporary software dedicated to the calculation of magnetic field distributions (e.g., Ansys Maxwell 3D, Comsol) allows performing the simulations of transients based on the field-circuit directly coupled finite element model (FEM) [4]; it is even possible to incorporate the required control loops essential to achieve magnetic levitation [7]
This model suffers from relatively long execution times and significant computation effort, as magnetic field equations need to be solved at every simulation step of the circuit and mechanical motion equations

Summary

Introduction

Investigations of transients in magnetic bearings require a computationally efficient simulation model that encompasses the control system. Contemporary software dedicated to the calculation of magnetic field distributions (e.g., Ansys Maxwell 3D, Comsol) allows performing the simulations of transients based on the field-circuit directly coupled FEM [4]; it is even possible to incorporate (into the simulation model) the required control loops essential to achieve magnetic levitation [7]. This model suffers from relatively long execution times and significant computation effort, as magnetic field equations need to be solved at every simulation step of the circuit and mechanical motion equations

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