• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.533-534
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• 2006

In this paper we propose a new model of a mini-pump with peristaltic motion and present the results of the finite element analysis of an electromagnetic micro actuator. The mini-pump consists of three diaphrams made of PDMS, three permanent magnets in cylinders, printed copper coils on glass substrates, and input and output port. The size of the mini-pump is $14\;{\times}\;40\;{\times}\;5.4$ mm3 and the permanent magnet diameter 6.2 mm $\times$ thickness 2 mm. The electromagnetic force applied on the magnet was about 0.84 N when the current of coils was 1 A, then the maximum displacement of the PDMS diaphram was about 2mm.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.267-274
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• 2009

To predict efficiency of Interior Permanent Magnet Synchronous Motors(IPMSM) and to cope with the demagnetization risk of permanent magnets used in the IPMSM, accurate iron analysis of the IPMSM is very important at the motor design stage. In the analysis, we calculate the operation condition such as rotor speed and current angle. and then, we analyzed the iron loss of the machine for electric vehicle according to its driving condition. From the analysis results, it was shown that the harmonic iron losses of stator are larger than before at field-weakening region. In addition, it was revealed that rotor iron loss mainly induced by stator slot-ripples is independent of current angle and only varied according to the speed.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.162-168
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• 2008

To predict efficiency of Interior Permanent Magnet Synchronous Motors(IPMSM) and to cope with the demagnetization risk of permanent magnets used in the IPMSM, accurate iron analysis of the IPMSM is very important at the motor design stage. In the analysis, we developed a new iron loss model of electrical machines for high-speed operation. The calculated iron loss was compared with the experimental data. It was clarified that the proposed method can estimate iron loss effectively at high-speed operation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.8
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• pp.717-726
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• 2010

For the application into a 1 kWh flywheel energy storage system(FESS), this paper presents the design scheme of radial and axial hybrid magnetic bearings which use bias fluxes generated by permanent magnets. In particular, the axial hybrid magnetic bearing is newly proposed in this paper, in which a permanent magnet is arranged in axial direction so that it can support the rotor weight as well as provide a bias flux for axial magnetic bearing. Such hybrid magnetic bearings consume very low power, compared with conventional electromagnetic bearings. In this paper, to stably support a 140 kg flywheel rotor without contact, design process is explained in detail, and magnetic circuit analysis and three-dimensional finite element analysis are carried out to determine the design parameters and predict the performance of the magnetic bearings.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.993-994
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• 2011

This paper presents the characteristic analysis of thermal behavior of a single-phase line-start permanent magnet motor(LSPM) for high-efficiency design. By analyzing of thermal behavior, it can consider demagnetization characteristics of permanent magnets. In addition, by calculating the allowable current density it will be able to reduce the size of the stator. For this reason single-phase LSPM is necessary to examine the thermal analysis. Thermal analysis was performed using heat source mapping, and it is verified by finite element method.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.745-752
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• 2012

Transverse flux machine (TFM) has been proved to be very suitable for high-torque, low-speed, and direct-drive situation in industry. But the complex structures and costly permanent magnets (PMs) are two key limitations of its wide range of applications. This paper proposes a new claw pole TFM (ACPTFM) which features an assembled claw pole stator and using the lamination steels material to overcome the complex structures. By combining response surface methodology (RSM) with design of experiment, an optimum design method is put forward to improve the PM's contribution to the torque in order to save the PM's amount. The optimum design results demonstrate the validity of the proposed optimum design method and the optimized model. Eventually, the finite-element analysis (FEA) calculation method, which is used in the optimization process, is verified by the experiments in a prototype.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.100-110
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• 2006

This paper presents the demagnetization and iron loss analysis of the single phase Flux Reversal Machine. It has a magnetic configuration similar to the switched reluctance machine but with multipole permanent magnets of alternate polarity on each stator salient pole embraced by concentrated coils. But it can be demagnetized by sudden over current and core losses increase because switching frequency is getting faster. This paper show demagnetization of permanent magnet and iron loss characteristic, and proposed a solution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.31-37
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• 2008

In this paper, we analyzed the dynamic behavior of magnetic fluid in a circular pipe with multiple permanent magnets. Magnetic fluid react on magnetic field against the normal fluid. In other words, magnetic fluid flow has the electromagnetism and fluid mechanics. So magnetic fluids has studied about the fluids properties and experiment. In this paper we studied the magnetic fluids velocity and pressure distribution for the novel type actuator. Because the velocity and pressure distribution is the important element of the magnetic fluids flow. First, we analyzed the Maxwell equation for the multiple permanent magnet and then concluded the governing equations for the magnetic fluid flow using the equation of Navier-Stokes. And, we simulated the dynamic behavior of magnetic fluid flow using the FEM(Finite Element Method). And we illustrated the relation between magnetic field and dynamic behavior of magnetic fluid flow.

• International Journal of Control, Automation, and Systems
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• v.2 no.3
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• pp.279-288
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• 2004

This paper presents a novel design for a tubular linear brushless permanent-magnet motor. In this design, the magnets in the moving part are oriented in an NS-NS―SN-SN fashion which leads to higher magnetic force near the like-pole region. An analytical methodology to calculate the motor force and to size the actuator was developed. The linear motor is operated in conjunction with a position sensor, three power amplifiers, and a controller to form a complete solution for controlled precision actuation. Real-time digital controllers enhanced the dynamic performance of the motor, and gain scheduling reduced the effects of a nonlinear dead band. In its current state, the motor has a rise time of 30 ms, a settling time of 60 ms, and 25% overshoot to a 5-mm step command. The motor has a maximum speed of 1.5 m/s and acceleration up to 10 g. It has a 10-cm travel range and 26-N maximum pull-out force. The compact size of the motor suggests it could be used in robotic applications requiring moderate force and precision, such as robotic-gripper positioning or actuation. The moving part of the motor can extend significantly beyond its fixed support base. This reaching ability makes it useful in applications requiring a small, direct-drive actuator, which is required to extend into a spatially constrained environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.380-384
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• 2010

A micromirror for a laser display system actuated by the electromagnetic force induced by the surface coil and the permanent magnet was designed and analyzed through the coupled physics analyses incorporating the electromagnetics, mechanics, and electrothermal analysis because the mechanical rotation of the micromirror is driven by the electromagnetic driving force. The proposed micromirror has two torsion beams to sustain the mirror plate which has surface coils on the top and the two permanent magnets exists on both sides of the micromirror for an external magnetic field source. The designed micromirror has the resonant frequency of 3.82kHz. When the magnetic field of the permanent magnet is 0.4T, the coil has 4 turns, and the current density of coil is 3.6A/$mm^2$, the estimated z axis displacement of the mirror plate edge is 0.23mm which corresponds to the rotation angle of $14.2^{\circ}$. When considering the joule heating in the current-carrying coil, the maximum temperature of the mirror plate is obtained as 300.045K, which induces the negligible changes in the rotation angle and the resistance of the coil.