Influence of Rotor Skew in Induction Type Bearingless Motor

To effectively control unbalanced vibration caused by grinding wheel mass unbalance, a new active control strategy for grinding wheel unbalanced vibration is proposed in the paper, the controllable electromagnetic force which is used to suppress vibration in control scheme originates from the principle of a bearingless motor having a radial magnetic force generation. First, induction electric spindle radial control force model and the force model which is exerted on grinding wheel are analyzed. And then, the dynamic model of induction-type flexural electric spindle-grinding wheel is modeled using finite element method. Finally, an active unbalanced vibration control system for electric spindle-grinding wheel is designed and simulated. The results show that the control scheme has significant effect on suppressing the unbalanced vibration of grinding wheel.

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Reluctance Force Magnetic Suspension Characteristics and Control for Cylindrical Rotor Bearingless Motors

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4035007 ◽

2017 ◽

Vol 139 (3) ◽

Cited By ~ 5

Author(s):

Lei Zhou ◽

David L. Trumper

Keyword(s):

System Dynamics ◽

Controller Design ◽

Suspension System ◽

Current Amplitude ◽

Magnetic Suspension ◽

Modeling And Control ◽

Bearingless Motor ◽

Induction Type ◽

Control Forces ◽

And Control

In this paper, the modeling and control of reluctance-force-based magnetic suspension in cylindrical rotor, smooth air-gap bearingless motors are presented. The full suspension system dynamics, including both the destabilizing forces due to the motor field and the active magnetic suspension control forces, are modeled, and a transfer function of the bearingless motor suspension plant is derived. It is shown that the suspension system dynamics in a bearingless motor depend on the motor winding current amplitude. This requires the magnetic suspension controllers to address the changing system dynamics and to stabilize the suspension under different driving conditions. A controller design with its gains changing with the motor winding current amplitude is proposed. The derived model and the proposed controller design are verified by experiments with a hybrid hysteresis–induction type bearingless motor. It is shown that the derived mathematical model provides an effective basis for loop-shaping control design for the reluctance-force-based magnetic suspension systems in bearingless motors, and the proposed controller design can stabilize the rotor's suspension under varying excitation conditions.

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Levitation and Torque Control of PM Synchronous and Induction Type Bearingless Motor

Volume 1B: 16th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc97/vib-4032 ◽

1997 ◽

Author(s):

Yohji Okada ◽

Shigenobu Miyamoto ◽

Satoshi Ueno ◽

Tetsuo Ohishi ◽

C. C. Tan

Keyword(s):

Magnetic Flux ◽

Radial Force ◽

Magnetic Bearing ◽

Torque Control ◽

Experimental Setup ◽

Radial Load ◽

Bearingless Motor ◽

Induction Type ◽

Torque Load ◽

Horizontal Type

Abstract General solution of levitation control applicable to PM synchronous and induction type rotating motor is presented. It is intended for a single rotor to have both functions of magnetic bearing and rotating motor. The rotational control is achieved with the traditional P pole magnetic flux, while the radial force is controlled with either P+2 or P−2 pole magnetic flux in the stator. In the previous work, the proposed general theory of levitated motor is successfully confirmed with no load experiments. In this paper, the load capability of the levitated motor is tested using a horizontal type experimental setup. The stator has 8 concentrated wound electromagnets, each of which is controlled individually by a DSP and power amplifier. The radial load is the gravity of the rotor, while the produced rotating torque is measured with a noncontact variable torque load system. The results obtained are discussed in detail.

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