Magnetically Levitated Homopolar Hollow-Shaft Motor (original) (raw)
Related papers
Novel Integrated Bearingless Hollow-Shaft Drive
Conference Record of the 2006 Ieee Industry Applications Conference Forty First Ias Annual Meeting, 2006
This paper describes a novel and compact design concept for contactless levitation and rotation of a wide annular rotor through the walls of a process chamber. In the proposed setup , a homopolar magnetic bearing biased by permanent magnets is combined with a high-pole-number segment motor. The paper describes the functional principle of the motor focusing on the design and the behavior of the drive. An experimental system is presented along with a comprehensive set of measurement results verifying the theoretical considerations.
Scaling of Magnetically Levitated Homopolar Hollow-Shaft Machines
2013
In this paper, we analyze scaling issues that arise when the size of a magnetically levitated hollow-shaft machine is varied, but the output power is kept constant. Reducing the size by a factor of two leads to a required increase in speed by a factor of about three. Because the losses of previously used topologies did not scale well we suggest and analyze a different topology: the combined homopolar magnetic bearing (CHB). The proposed design methodology has been experimentally verified in a prototype product.
This paper analyzes challenges that arise when the rotational speed in magnetically levitated hollow-shaft PMSMs is increased. Going to higher speeds highlights the advantages of such machines as being contact and contamination free, but leads to considerably higher losses. We propose a model and supply experimental data and simulations to subdivide losses into different categories with regard to specific optimizations. We particularly focus on the high rotor shell eddy current losses specific for this machine.
Novel Magnetically Levitated Two-Level Motor
IEEE/ASME Transactions on Mechatronics, 2000
Several processes in chemical, pharmaceutical, biotechnology, and semiconductor industry require contactless levitation and rotation through a hermetically closed chamber wall. This paper presents a novel concept that combines crucial advantages such as high acceleration capability, large air gap, and a compact motor setup. The basic idea is to separate a homopolar bearing unit axially from a multipolar drive unit on two different height levels. Hence, the proposed concept is denominated as "magnetically levitated two-level motor." In this paper, the bearing and drive functionalities are explained in detail and design guidelines are given based on analytic equations and electromagnetic 3-D simulations. Furthermore, the influence of nonidealities such as saturation and coupling effects is evaluated and included in the design. Finally, extensive measurements on an experimental prototype exemplify the design considerations and prove the excellent performance of the new concept.
DEVELOPMENT OF A MAGNETICALLY BORNE ELECTRICAL MOTOR PROTOTYPE
2000
The magnetic bearing is an electro-mechanical device that maintains the rotor of an equipment magnetically levitated. Besides allowing for a contact less working condition, resulting in a system without mechanical wear, this device presents other advantages, such as self-balancing, vibration control, self-monitoring, possibility of equipment encapsulation and high operation speed, with high reliability and reduced maintenance. Taking these advantages into account, magnetic bearings are becoming technologically competitive in many applications such as turbo-generators, pumps, compressors, fabrication machines, gyroscopes, centrifuges etc. It should be realized that since the absence of friction eliminates the need of lubrication, the magnetic bearings are ideal for airspace applications and for radioactive environments. Moreover, due to this same characteristic, it is an energy-saving device, which is, perhaps, the main reason for its utilization in new equipments. In order to gain a better understanding of this technology, a prototype of an integrally levitated electrical motor has been developed. The mechanical, magnetic and electric conceptions of the bearings have been already described in previous works, including the mechanical engineering considerations related to the design, fabrication and mounting of the magnetic bearings on the equipment. In this work, the successfully design and implementation of the displacement controllers are described. Simulations and experimental results show the static and dynamic performance of the bearings.
Bearingless Five-Axis Rotor Levitation with Two Pole Pair Separated Conical Motors
2009 IEEE Industry Applications Society Annual Meeting, 2009
In some high performance applications, such as high speed rotating machinery, systems where access for maintenance is limited, or operating environments with extreme temperatures and pressures, motors without mechanical bearings would be preferred. This paper presents the theory, simulation, and lab results of a new type of fully magnetically levitated bearingless motor. The motors are wound without internally connecting the pole pairs, and force is controlled by varying rotor reference frame d-axis current to each pole pair. This in turn raises or lowers the flux caused by the permanent magnets, creating a flux imbalance on the periphery of the rotor [1], which in turn creates a net force on the rotor. The conical shape of the motor allows forces to be created in both radial and axial directions, allowing these motors full 5-axis levitation.
2011 IEEE Energy Conversion Congress and Exposition, 2011
In standard motor applications, rotor suspension with traditional mechanical bearings represents the most economical solution. However, in certain high performance applications, rotor suspension without contacting bearings is either required or highly beneficial. Examples include applications requiring very high speed or extreme environment operation, or with limited access for maintenance. This paper expands upon a novel bearingless motor concept, in which two motors with opposing conical air-gaps are used to achieve full five-axis levitation and rotation of the rotor. Force in this motor is created by deliberately leaving the motor's pole-pairs unconnected, which allows the creation of different d-axis flux in each pole pair. This flux imbalance is used to create lateral force. This approach is different than previous bearingless motor designs, which require separate windings for levitation and rotation. This paper examines the predicted and achieved suspension performance of a fully levitated prototype bearingless system. I.
Homopolar bearingless slice motor in temple design
2017 IEEE International Electric Machines and Drives Conference (IEMDC)
This work describes a concept of a magnetically levitated homopolar bearingless slice motor in temple design. The proposed setup consists of two oppositely magnetized permanent magnets on the rotor and stator and provides high axial stiffness. The fluctuation of the air gap field for torque generation is generated with a cross-shaped rotor iron. Compared to a diametrically magnetized drive, this concept achieves three times the axial stiffness without increasing the radial stiffness and is better suited for systems with large air gaps. A drawback is the low torque capacity. Its operating principle is described and a working prototype is presented including simulation and measurement results.
Force analysis of linear induction motor for magnetic levitation system
Journal of Applied Physics, 2010
This paper presents the analyses of thrust and normal forces of linear induction motor (LIM) segments which are implemented in a rotating ring system. To obtain magnetic levitation in a cost effective and sustainable way, decoupled control of thrust and normal forces is required. This study includes the design of a static test setup from which the measurement results are compared and verified with the derived analytical methods and finite element simulations. The comparison shows significant correlation of the thrust and normal forces as function of the slip frequency.
Magnetically Levitated Slice Motors
IEEE Transactions on Industry Applications, 2011
This paper provides a comprehensive overview of different concepts of magnetically levitated slice motors with ring-shaped rotors that differ in their construction and the way the bearing forces and drive torque are created. After a general classification of magnetic bearings and the description of the technical principle of the topologies, the design constraints for a fair topology comparison are specified. Mechanical, magnetic, electrical, and thermal design considerations are discussed and supported by 3-D finite-element method simulations. Four promising motor topologies are compared qualitatively and quantitatively by different criteria, such as acceleration behavior, compactness, bearing stability, and complexity of the control. The comparative evaluation is supported by performance measurements on laboratory prototypes.