• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.897-898
• /
• 2006

This paper presents test results for the speed control system of PMSM (Permanent Magnet Sychronous Motor). The PMSM has higher efficiency and torque per volume than other motors because PMSM use permanent magnet of high energy density instead of field winding. In this paper, current and speed control of PMSM using DSP was accomplished.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.893-894
• /
• 2006

This paper presents a design and analysis solutions for the general class and control parameter estimation of slotted iron-cored Permanent Magnet Linear Synchronous Motor with Halbach magnetization stator and 3-phase winding mover. In our design and analysis, stator consisting of permanent magnets and slotted iron-cored coil mover are treated in a uniform way via magnetic vector potential. For one such motor structure, we give analytical formulas for its magnetic field, back electromotive force and trust force. Moreover, the detent force are calculated by the relative permeance function. In good agreement with the estimated values from the analyses, the experimental results and Finite Element Method (FEM) confirm the validity of the design and analysis framework.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.769-770
• /
• 2006

This paper proposes the design method of a magnetic suspension that can control external vibration caused by low frequencies on the external vibrations by low frequencies. The magnetic suspension with individual controls is able to compensate the vibrations unlike a mechanical suspension. In the magnetic suspension, two characteristics are required. Firstly, magnetic motive force(MMF) by armature winding must be increased linearly. Secondly, identical magnitude of output force should be produced as direction of MMF. In this paper, axis-symmetric finite element analysis is used for magnetic field analysis. In order to optimize magnetic suspension, response surface methodology combined with experimental design is applied to investigate the characteristics and optimize the magnetic suspension for vibration -free table.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.232-234
• /
• 1994

In this paper. to estimate starting torque of synchronous motor by simple test, we propose a new method which is the combination of commercial tests and single phase AC applied test of synchronous motor. A driving characteristic was examined when field winding is supplied a de and chopper current. The starting characteristics are assumed and agreed with actual data.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.153-155
• /
• 1994

Electric machines such as motors which have moving parts are desgined for producing mechanical force or torque. The accurate calculation of electromagnetic force and torque is important in the design these machines, Electromagnetic force calculation method using the results of Finite Element Method(FEM) has been presented variously in 2-D problems. Typically the Maxwell's Stress Tensor method and the method of virtual work are used. In the problems including current source, magnetic vector potentials(MVP) have mostly been used as an unknown variables for field analysis by numerical method; e, g. FEM. This paper, thus, introduces both methods using MVP in 3-D case. To verify the usefulness of presented methods, a solenoid model is chosen and analyzed by 3-D and axisymmetrical FEM. In each case, the calculated force are tabulated for several mesh schemes.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.11
• /
• pp.1657-1662
• /
• 2017

Rotor bar faults in induction machines, which are a part of main distribution of power system, can even stop the entire system by causing contact between a stator and a rotor. There are two methods of diagnosing rotor bar faults in induction motors, online and offline tests, and existing diagnosis methods have many limitations which can lead to misdiagnosis. This paper proposes a potable rotor bar faults diagnosis system based on single phase rotation test, one of offline test methods, which detects rotor bar faults through impedance interpretation by exciting AC current in a stator winding. The test was conducted on a motor of 0.4kW in the laboratory and a motor of 1500kW in industry field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.493-494
• /
• 2008

During the last years hollow core insulators started their success story in the field of high voltage engineering for electrical apparatus, substituting porcelain insulators. The termination, also named top and bottom fittings are used for the connection to the rest of the electrical apparatus. The top and bottom flange are attached to the composite to transmit mechanical load and also ensure the gas tightness. They are bonded by epoxy glue with a glass transition temperature of about $130^{\circ}C$-$150^{\circ}C$ the glass reinforced epoxy tube of filament winding. This paper describes the results of a study on the bonded joints of fiber reinforced epoxy tube and cast aluminum. This suggests that surface roughness and glue types play an important role in evaluating of gas sealing capability on the flange and fiber reinforced epoxy tube in the composite hollow bushing.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.879-881
• /
• 2000

This paper treats the electromagnet type linear synchronous motor with induction operation. The proposed motor consists of the primary winding energized by variable frequency supplies and the secondary having an additional solid-conductor besides the field finding. The conductor is useful for not only the self-starting but also the damping effect In the synchronous drive. From the investigation by the experiment and the finite element analysis coupled with both electric circuit and motion equation we verify that the proposed motor is effective for practical use.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.04a
• /
• pp.9-12
• /
• 2004

Presented is a preliminary design concept of the carbon-glass hybrid composite rebars for the application in the construction field. A glass fiber rod with indentation is used for the core of the rebar. Carbon fibers are placed over the glass core by pultrusion. To increase the mechanical locking force and bonding surface, carbon filament windings are added in the hoop direction over the carbon face. Finite element analysis and test were conducted to evaluate the effective stiffness and strength of the rods. The results show that the effective axial stiffness of the rebar with indentation are about $50\%$ of the straight rebar.

• Journal of Magnetics
• /
• v.21 no.2
• /
• pp.249-254
• /
• 2016

Recently, electric vehicles have got significant attention because it is more eco-friendly and efficient than internal combustion engine vehicles. Instead of an internal combustion engine, the electric vehicle has a motor for propulsion. The permanent magnet synchronous motor which has permanent magnet instead of field winding in the rotor has especially higher efficiency and power density than other types of motor. When the irreversible demagnetization is occurred, drivers are exposed to high risk of accident by the fault operation of motor. Therefore, the irreversible demagnetization of permanent magnet should be detected to reduce the risk of accident. In this study, the demagnetization diagnosis method based on the result of locked rotor test is proposed. Based on short measurement time, the proposed diagnosis method aims to detect the demagnetization fault when an electric vehicle is at a complete standstill. The proposed method is verified through the finite element analysis.