• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.5
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• pp.690-697
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• 2012

Novel 8/10 bearingless switched reluctance motor, which can control rotor radial positions with magnetic force, is proposed. The motor has combined characteristics of switched reluctance motor and magnetic bearing. This paper proposes a air-gap control system method of suspending force control in a bearingless switched reluctance motor (BLSRM). The proposed radial force control scheme is independent to the torque winding current. A PI direct current control (DCC) controller and look-up table are used to maintain a constant rotor air-gap. From the analysis and the experimental results, it is shown that the proposed strategy is effective in realizing a naturally decoupled radial force control of BLSRM.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.3
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• pp.336-346
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• 2012

In this paper, a novel bearingless switched reluctance motor (BLSRM) with hybrid stator poles is proposed. The structure and operating principle are presented. In order to describe the design methodology clearly, analytical torque and radial force models are established. Further, basic design procedure is described. The numbers of phases and poles have important influence on the selection of structure. These effects, along with sizing of machine envelope and internal dimensions, make the machine design an insight-intensive effort. Effect of pole arcs and air-gap length on the production of torque and radial force are analyzed in detail. Mechanical design factors such as hoop stress and first critical speed are also considered. Based on the above analysis, the characteristics of the proposed BLSRM are analyzed. A prototype motor is designed and manufactured. The validity of the proposed structure is verified by the experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.746-752
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• 2011

In this paper, a novel bearingless switched reluctance motor (BLSRM) with double stator is proposed. This motor has two stators. Torque stator is outside, which mainly produces rotational torque. Radial force stator is inside, which mainly generates radial force to suspend the rotor. A novel structure and operating principle are presented. And characteristics of the proposed structure such as magnetic flux distribution, inductance, torque and radial force are analyzed through finite element method. From the analysis, the proposed BLSRM has linear characteristic of radial force and independence from torque current.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.766-772
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• 2013

Modeling and control of radial force in the double stator type bearingless switched reluctance motor (BLSRM) is researched. The rotational torque is controlled independently from the radial force control. And the radial force is constant which is independent from the rotor position. In order to realize steady suspension, analytical models of torque and radial force for the proposed structure are derived. Meanwhile, in order to realize steady suspension, control scheme for proposed BLSRM is proposed. In the control method, the radial force can be controlled in arbitrary direction and magnitude by selecting some combinations of radial force windings. The validities of structure and control method are verified by the experimental results.

• Journal of Electrical Engineering and Technology
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• v.6 no.1
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• pp.94-103
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• 2011

This paper presents a novel bearingless switched reluctance motor (BLSRM) with decoupled torque and suspending stator poles. BLSRM is different from conventional bearingless switched reluctance motors (SRMs) because its suspending poles are separated from the torque poles. Perpendicularly placed suspending poles are designed to produce a continuous radial force to suspend the rotor. Due to the independent suspending and torque poles, BLSRM produces a suspending force with excellent linearity according to the rotor position and independent characteristics of the torque current. The air-gap is easier to control than in conventional SRMs with their linear and independent characteristics. Furthermore, to verify the proposed structure, a mathematical model for the suspending force is derived. Finite element analysis is also employed to compare BLSRM and conventional SRMs expressions of suspending force. A prototype motoris designed and manufactured to verify the effectiveness of the proposed bearingless structure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.57-64
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• 2010

In this paper, a novel Bearingless Switched Reluctance Motor(BLSRM) with the shoe rotor pole in order to minimize the torque ripple and the suspension force ripple at an overlap position is proposed. For reduction the torque ripple and the suspension force ripple at an overlap position, the fringing flux is used for the main flux. This configuration of the rotor pole results in more average torque with high suspension force. In addition, this paper is compared the transient characteristics using the inductance look-up table. The torque, radial force and flux density are analyzed by finite element method.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.208-214
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• 2011

In this paper, a characteristics analysis and calculation of the suspending force of a novel bearingless switched reluctance motor (BLSRM) with hybrid stator poles is proposed. The operating principle and permeance are calculated to find an appropriate control scheme for a proposed motor. Furthermore, a mathematical model for suspending force is derived. Finite element analysis is also employed to compare with the expressions for suspending force. Finally, the validity of the structure and the mathematical model is verified by simulation results.

• Journal of Power Electronics
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• v.9 no.6
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• pp.845-853
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• 2009

This paper presents a novel hybrid pole BLSRM (Bearingless Switched Reluctance Motor) and its radial force control scheme. The proposed hybrid pole BLSRM has separated radial force poles and rotating torque poles. According to the FEM analysis, the proposed BLSRM has an excellent linear characteristic of radial force and controllability that is independent from the torque current. The radial force can be produced by the radial force winding which is wound at the separated radial force poles. The rotating torque is produced by the excitation current of the torque windings which are wound at the torque pole. The proposed radial force control scheme is independent of the phase torque winding current. A simple PID controller and look-up table are used to maintain a constant rotor air-gap. The proposed BLSRM and its radial force control scheme are verified by FEM analysis and experimental tests.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.845-847
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• 2015

A suspending force control based on fuzzy logic control is proposed to apply on a novel hybrid bearingless switched reluctance motor(BLSRM) which has separated torque and suspending force pole. Due to the unique structure, the suspending force control system can be easily decoupled from torque control system. In this paper, two fuzzy controller targeted at x-axis direction and y-axis direction are adopted to maintain the shaft at center position, which is very necessary for stable operation of BLSRM. By replacing the traditional PI block with modified fuzzy logic controller, the suspending system can behave a good performance, and the proposed scheme can be verified by simulation results.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.682-684
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• 2015

A 12/14 bearingless switched reluctance motor (BLSRM) with hybrid stator poles has been proposed due to the outstanding decoupling characteristics between the torque and suspending force. However, the motor is a two-phase motor. The output torque of the motor has torque dead zone and high torque ripple. Hence, the motor cannot self-start at some rotor positions. To solve the self-starting problems and reduce the torque ripple, a stepped rotor is proposed in this paper. Then, the motor with the stepped rotor is optimally designed. In the new designed motor, the majority parameters are kept the same with those of original motor; only the torque pole arc and rotor pole shape are optimally designed. The characteristics of the redesigned motor, such as inductance, torque and suspending force, are analyzed and compared with those in the original motor. Finally, the effectiveness of the proposed method is verified by the simulation results.