• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.564-569
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• 2012

This paper proposes a hybrid-excited linear synchronous motor (LSM) that has potential applications in a magnetically levitated vehicle. The levitation and thrust force characteristics of the LSM are investigated by means of three-dimensional (3-D) numerical electromagnetic FEM calculations and experimental verification. Compared to a conventional LSM with electromagnets, a hybrid-excited LSM can improve levitation force/weight ratios, and reduce the power consumption of the vehicle. Because the two-dimensional (2-D) FE analysis model describes only the center section of the physical device, it cannot express the complex behavior of leakage flux, which this study is able to predicts along with levitation and thrust force characteristics by 3-D FEM calculations. A static force tester for a hybrid-excited LSM has been manufactured and tested in order to verify these predictions. The experimental results confirm the validity of the 3-D FEM calculation scheme for the description of a hybrid-excited LSM.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.2
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• pp.26-30
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• 2016

This paper presented an optimum design of a perpendicular PMDSLSM (Permanent Magnet Double-sided Linear Synchronous Motor) to minimize the detent force. As an optimum method, the response surface method was used and 3D finite element method for the calculation. The design variables of the machine were the primary core width and thickness, and magnet width, thickness and length. Object functions were to minimize the detent force and maximize the thrust of the basic model. The results showed that the thrust force of the optimum design increased from 82.1N to 90.2N and detent force decreased from 15.2N to 2.8N, respectively, compared to the basic model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.722-726
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• 2007

In this paper we deal with a design of the integral sliding mode controller to suppress the disturbance force acting on the suspension system of the magnetically levitated train system. One of the important factors that cause the disturbance force acting on the suspension system comes from the low propulsion speed of linear induction motor. In this paper integral sliding mode controller is employed to reject the disturbance force produced by the propulsion system of the linear induction motor. In order to show the effectiveness of the designed controller a dynamic simulation is utilized and the sliding mode controller without integral compensator is compared with the proposed integral sliding mode controller to suppress the disturbance force.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1733-1740
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• 2004

In the transverse flux linear induction motor(TFLIM) with the general secondary composed of conductor and back-yoke, there exists a magnetized force into the normal direction or the air-gap direction of the thrust motion as well as the thrust force. Therefore, the various methodologies have been tried to use the normal force by the two independent control variables of the multi-phase input. But, as the force depends inevitably and strongly on the thrust force, it is essential to decouple both forces for two control index. In this paper, we suggest a novel approach capable of compensating the couple between both forces and the control index by using the DC-biased multi-phase input, and then realizing the independent control of TFLIM.

• 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.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1081-1082
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• 2011

In order to predict the accuracy of the linear motion machine tools, the force characteristics such as the detent force, the attraction force and the moment are estimated by analytical method or FEM. In this paper, we proposed the analytical calculation process for the force characteristics of a linear motor. The analytical results are good agreement with FEM one. They could be used for the precision prediction simulator with the information of linear bearings, encoders, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1088-1094
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• 1997

An indirect cutting torque and cutting force estimation method is presented. This method uses a time-domain model between the spindle motor power, which calculated form measured spindle motor current and voltage. Spindle motor power is linear with cutting torque in this model. The cutting force is proportional to the cutting torque. Using trial cut, parameters are determined. Static sensitivity is suitable for various cutting conditions. The presented method is verified under several cutting tests on the CNC horizontal machining center.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.584-587
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• 1992

Because linear motor directly drives linear motion, it does not need conversion equipment such as belt and gear. Especially linear pulse motor provide more precise positioning and large force of linear pulse motors. As current manufacture technic of linear pulse motor is much to be desired at home. This motor lay out to make use of computer aided design program, In this paper the experimental motor is 2-phases 4-poles hybrid pulse motor which has teeth per pole Simulation program is divided its function into 4 parts - air gap permeance analysis, permanent magnet & non-linear core operating point determine, winding configuration, leakage flux analysis. It is possible to make motor static and magnetic characteristics for this simulation program. Also, by varying input parameters of the program, experimental motor is to be compared to motor characteristics.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.257-262
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• 2001

In this paper, a linear ultrasonic motor using piezoelectric ceramics was fabricated, and its operation characteristics were investigated. A linear ultrasonic motor using L$_1$-B$_4$model was composed of a stator and a rotor, and a stator was composed of piezoelectric ceramics and a elastic body. When applied frequency and voltage were 58.4kHz and 56V respectively, the feeding speed of the motor was 19.8 cm/s. A linear ultrasonic motor could be moved in left and right directions by the phase difference. Feeding speed and feeding force of a linear ultrasonic motor could be controlled by applied voltage. A linear ultrasonic motor had a droping torque-speed characteristic. The maximum efficiency of linear ultrasonic motor was 2.14%. Therefore, this linear ultrasonic motor can be expected to be used for a card-forwarding device, such as a card reader device and so on.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.85-89
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• 2007

Linear ball guideways have been used recently in precision or ultra-precision positioning devices. However, when the inner balls begin to roll or the moving direction reverses, these guideways are subject to rolling friction or nonlinear spring behavior. An ultra-precision device with a linear motor, referred to as a 'tunnel actuator' (TA), has been constructed to measure these phenomena. The application of a TA is beneficial for two reasons: it mostly cancels the attractive magnetic force between the stator and mover (armature), and its magnetic flux leakage is very low. The influence of the nonlinear spring behavior in ball guideways was investigated in this study using the pure driving force from a TA. The equilibrium between the driving force from the TA and the nonlinear spring force provided great accuracy for a positioning stage using a linear ball guideway.