• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.2
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• pp.53-58
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• 2001

This paper describes a moving mesh technique for dynamic characteristics analysis of permanent magnet linear synchronous motor with the secondary aluminium sheet. The moving mesh technique applied to the linear induction motor can be used to analyze the linear synchronous motor with the rectangular permanent magnet. But in case of the permanent magnet with taper, the shape of the permanent magnet is presented. The time-stepped finite element method is used for the dynamic characteristics simulation of the permanent magnet linear synchronous motor, The results of application example(hysteresis current controlled inverter fed control) such as thrust, current and flux plots are shown.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.514-521
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• 2000

This paper presents a direct thrust control scheme for permanent magnet linear synchronous motor(PMLSM) by using digital signal processor(DSP). And a simulation method for the direct thrust control of a permanent magnet linear synchronous motor using the equivalent circuit is presented. The detent force that was obtained by cubic spline method is considered in the simulation. Thrust correction coefficient is utilized to estimate actual thrust on the direct thrust control, which considers the longitudinal end effect due to the finite core length of the permanent magnet linear synchronous motor. The motor self inductance, the initial flux linkage by the permanent magnet is calculated in advance by the finite element analysis, and then the direct control simulation is carried out. As the results, thrust, current and speed are shwon.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.3
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• pp.138-144
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• 2000

The detent force caused by the interaction of magnets with the teeth of a armature core deteriorates the driving performance of a permanent magnet linear synchronous motor. In this paper, we analyze the fields and forces of a linear synchronous motor with segmented or skewed magnet arrangement according to lateral overhang length of permanent magnets. For the analysis, the 3-dimensional equivalent magnetic circuit network method is used. The detent force and the static thrust are analyzed according to the segmented or skewed angle and the overhang length of permanent magnets, and the optimal angles that the detent force is minimized are found out in each case. The analysis results are compared with the experimental ones and shown a reasonable agreement.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.146-150
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• 2001

Comparison on the performances between the Halbach array type permanent magnet linear synchronous motor (HA-PMLSM) and the convensional array type permanent magnet linear synchronous motor (CA-PMLSM) was made with finite element analysis (FEA) and experiment. The HA-PMLSM is seen to be superior to the CA-PMLSM. Optimum ratio of magnet length to slot pitch of the HA-PMLSM which reduces the detent force was determined. Also, Comparison of forces of the HA-PMLSM and the CA-PMLSM with minimum detent force is presented.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.12B no.1
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• pp.1-6
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• 2002

The severe problem in improving the positioning precision of a permanent magnet linear synchronous motor (PMLSM) is the large detent farce caused by the permanent magnet arrangement. It is generally an undesired effect that contributes to the torque ripple, vibration and noise of machine. The detent force is arisen from the difference of the position of a permanent magnet end and a tooth position. In this paper, the four methods to reduce detent force were studied and analyzed. The methods are adjusting the width of permanent magnet, varying the shape of armature teeth, relocating the permanent magnet, and adjusting the width of permanent magnet and relocating the permanent magnet at the same time. To analyze the detent farce according to flour methods, a two-dimensional Finite Element Analysis [FEA] was used and we compared with the ratio of reduction of the detent farce according to the flour methods.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.788_789
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• 2009

The cogging force of a permanent-magnet linear motor is a major component of the detent force, but unfortunately makes a ripple in the thrust force and induces undesired vibration and acoustic noise. In this paper, Coupling Particles Swarm Optimization is applied to optimization the shape of permanent magnet linear motor by minimizing the undesired vibration and acoustic noise in the thrust force and also considering the maximum thrust force. The result shows that the 9-pole 10-slot PMLM removes almost of the cogging force while giving a big thrust force.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.53-59
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• 2005

In this paper, optimum shape design of permanent magnet in slotted type Permanent Magnet Linear Synchronous Motor(PMLSM) is progressed for minimization of detent force owing to structure of slot-teeth and thrust ripple by harmonic magnetic flux of permanent magnet. In order to reduce remodeling time as changing design parameter for Permanent Magnet shape optimization, the moving model node technique was applied. The characteristics of thrust and detent force computed by finite element analysis are acquired equal effect both skewed basic model and optimum model which is optimization of permanent magnet shape. In addition to, thrust per unit volume is improved 4.l2[%] in optimum model.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.923-925
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• 2008

As known generally, when permanent magnets whose poles are upward and downward in order, arranged into the circumferential direction rotate under the conducting plate, the rotating force acts on the plate as well as the repulsive force. If the magnetic field by the magnet wheel(the above rotating permanent magnets) is partially shielded, the magnet wheel over open region can be a linear induction motor. The distinct feature from induction motor is that the traveling magnet field is produced by the moving permanent magnet instead of ac current. Furthermore, a variation of the open region changes the direction of the thrust force. In this paper, we introduce a concept of the linear actuator using the magnet wheel. Under the above shielding condition, a few simulation results and its verification from a simple test setup are described.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.11
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• pp.547-554
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• 2006

The detent force of a permanent magnet linear motor(PMLM) consists of the end force and cogging force, and should be reduced for high precision purpose applications. The cogging force comes from the electromagnetic interaction between the permanent magnets and interior teeth(or the slots) of the stator, and of which the magnitude depends on the ratio of the numbers of the armature and permanent magnet poles as well as the geometrical shape of the permanent magnet and armature pole. In order to reduce the cogging force of a PMLM, this paper proposes a new configuration which has 9 permanent magnet poles and 10 armature winding slots. By theoretical investigation of the principle of cogging force generation and simulating using finite element method, the proposed PMLM configuration is proven to give much less cogging force than the conventional configuration which has 8 permanent magnet poles and 12 armature winding slots. A proper winding algorithm, modified (A, A, A) winding method, for the proposed configuration is also suggested when the proposed PMLM is operating as a 3 phase synchronous machine. A theoretical and numerical calculation shows that the proposed configuration makes slightly bigger back-emf and thrust force under same exciting current and total number of winding turns condition.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1695-1702
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• 2015

This paper presents the characteristic analysis and experiment of force characteristics in permanent magnet linear synchronous motor for accuracy prediction of linear motion machine tools. In particular, the pitching moment resulting from attraction force ripple has been analysed and tested. Firstly, we analysed the characteristics of detent force, attraction force, and pitching moment in permanent magnet linear synchronous motor according to the design techniques such as auxiliary teeth, chamfering, and permanent magnet skewing. In addition, we suggested the experimental set for measurement of pitching moment. Finally, the results from measurement shows the good agreement with those obtained from finite element analysis results.