Robust Stability of the Lorentz-type Self Bearing Servomotor

Stephens, Lyndon Scott; Chin, Hooi-Mei

doi:10.1299/jsmec.46.355

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…where k is the number of turns in a concentrated winding and 2α is the winding pitch angle. Then the motoring torque produced by these currents can be obtained, using Lorentz law, as (4) where r and l are the effective radius and length of stator windings respectively. This suggests that we can control the system like a standard synchronous AC motor by adjusting the phase shift ψ as its torque angle.…”

Section: Design Principlementioning

confidence: 99%

“…Since the end of the 1980s, extensive research has been carried out, resulting in the development of various kinds of integrated motor-bearing systems [2]. The new integrated motor-bearing systems that have been proposed in recent years deserve much attention, as they employ the Lorentz force for rotor position regulation as well as motoring [3][4][5][6][7]. Unlike the Maxwell force, the bidirectionality and good linear properties of the Lorentz force can simplify the analysis and design of the system when it is applied to stabilize the rotor position.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Compensation of Runout and High Order Harmonic Effects in Lorentz Force Type Integrated Motor-Bearing System

Park

Lee

2005

Volume 1: 20th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C

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An integrated motor-bearing system integrates the functions of an active magnetic bearing and an electric motor into a single unit. Because this system requires the simultaneous generation of torque and radial control force, there will inevitably be undesired high order harmonic components in the rotating magnetic field, which will result in torque ripple and radial force distortion. Sensor target runout is a severe excitation source and, as such, causes a lot of vibration. In this paper, we propose an experimental compensation procedure for the oscillation and coupling of torque and radial force using a digital controller of the Lorentz force type integrated motor-bearing system in a dual disk rotor configuration. After the compensation of high order harmonics, the runout profile and rotor unbalance are identified by the extended influence coefficient method. The proposed scheme does not require complicated analysis or modeling of high order harmonic effects, and it can also compensate for manufacturing errors. The experimental results confirm that this compensation method effectively attenuates the rotor vibration throughout the operating range of rotational speeds.

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Section: Design Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental Compensation of Runout and High Order Harmonic Effects in Lorentz Force Type Integrated Motor-Bearing System

Park

Lee

2005

Volume 1: 20th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C

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“…To eliminate the displacement sensors, alternative methods have been proposed [2]- [6]. These methods can be also applied to bearingless motors [7][8][9][10][11][12][13][14][15][16], which combines a motor function and a magnetic suspension, magnetically. In bearingless motors, the radial displacement sensorless approach is more difficult due to the motor revolving magnetic field and the electric noise induced by the PWM voltage source inverters [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

A PWM harmonics elimination method in simultaneous estimation of magnetic field and displacements in bearingless induction motors

Chibá

Santisteban

2011

2011 IEEE International Electric Machines &Amp; Drives Conference (IEMDC)

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In this paper, a novel estimation method of both revolving magnetic field and rotor radial displacements is proposed. Four auxiliary windings, i.e., search coils, are wound around the stator teeth in an induction type bearingless motor. The coils are connected to a high frequency voltage source. The middle point voltages between two search coils are processed with simple analog circuits to obtain radial rotor displacements. These middle point voltages are affected by harmonic voltages generated by a general-purpose PWM inverter connected to motor terminals. Thus, two methods of noise elimination are proposed and tested. The theoretical analysis and the successful experimental results validate the proposed approach.

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