• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1054-1056
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• 2003

The slotless Permanent-Magnet Linear Synchronous Motors (PMLSM) have been developed for factory automation, transportation applications, wafer steppers, conveyance system, and so on. The current analysis and design are treated in air-cored PMLSM. This paper presents a design and analysis solutions for the general class of iron-cored Permanent magnet Linear Synchronous motor (PMLSM). In our design and analysis, rotor consisting of permanent magnets and slot less iron-cored coil stator are treated in a uniform way via vector potiential. For one such motor structure we give analytical formulas for its magnetic field, opitimal permanent magnet and winding coil thickness, trust force. We also provide comparisons of three types in Halbach, vertical, and horizontal magnet array.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.41-43
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• 2009

This paper deals with determination of parameters of permanent magnet linear synchronous machine(PMLSM) for high thrust and improvement of speed performance. To satisfy these characteristics, PMLSM with double-sided PM mover and slotless ring-winding stator is presented. And using multilaver method, this paper analyzes the electromagnetic field phenomena and estimates parameters such as back-EMF and thrust constant. These parameters are used to derive DC link voltage of voltage source inverter with space vector pulse width modulation(SVPWM) using a digital signal processor and encoder pulse signal. The DC link voltage is one of the most important factor for accurate design. It enables to determinate dynamic operating range of system. Hence, performance evaluation is performed through dynamic modeling. Finally, in this paper, dynamic characteristics according to DC link voltage are presented as experiment result.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.27-32
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• 2017

In this paper, slot less type high-speed and compact motor was designed. it was selected through change of stator coil distribution for the optimal performance of the motor. In this paper, designed motor was expected to be very vulnerable to heat dissipation in a compact motor. Therefore, to ensure reliability in the design result, winding and permanent magnet damage caused by the losses of motor was analyzed by thermal analysis and demagnetization analysis. Using the result, whether motor burnout was confirmed by motor performance degradation and insulation breakdown.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.63-65
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• 2004

The recent advancement in the power electronic technique has increased the use of induction motor fed by inverter using high-frequency switching devices. Also the tendency is toward larger size and higher voltage. Therefore, The IGBT (Insulated-Gate Bipolar Transistor) that is high switching frequency element has been using increase. But, The switching surge voltage was occurred by high switching frequency of inverter has appeared a voltage doubling in the motor input terminal due to mismatching of cable characteristic impedance and motor characteristic impedance. Actually, The Switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. The short during rise time of switching surge and cable length is increased, the maximum transient voltage seen at the motor terminals increases. In this paper, Analyzed switching surge transient voltage of power cable pulling is used EMTP(Electromagnetic Transient Program) at the induction motor terminal and in cable.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.807-811
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• 2011

When the high voltage motor fails in power plants, there will be an occurrence where the generator's output would be reduced or the generators would trip. Despite of these effects, the causes of deterioration of the high voltage motor is very seldom investigated. In this paper, the collected data which tested in the field over 10 years have been treated statistically, and analyzed to correlate the insulation deterioration of high voltage motor and installation environment, number of start/stop, and service life. Moreover, the proper period of insulation test is developed to map out maintenance strategy and reduce maintenance costs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.141-149
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• 2007

This paper introduce to improve the reliability of the expected service life and the insulation condition evaluation of the high voltage induction motors by assessing, comparing and analyzing the correlation between the dielectric properties of the off-line insulation diagnostic test and dielectric strength on the insulation breakdown test. The insulation diagnostic tests include insulation resistance, polarization index(P.I.), dissipation factor($tan{\delta}$), maximum partial discharges($Q_{max}$) and AC breakdown test. This study evaluated the correlation between insulation diagnostic test and AC breakdown test for stator winding of high voltage induction motor. On the basis of these test results, we expect that this study can be used for effectively assessing the results of insulation diagnostic tests for similar class induction motors in service at industrial field.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1542-1547
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• 2012

Asynchronous phenomenon occurs on the synchronous generators under power system when a generator's amplitude of electromagnetic force, phase angle, frequency and waveform etc become different from those of other synchronous generators which can follow instantly varying speed of turbine. Because the amplitude of electromagnetic force, phase frequency and waveform differ from those of other generators with which are to be put into parallel operation due to the change of excitation condition for load sharing and the sharing load change, if reactive current in the internal circuit circulates among generators, the efficiency varies and the stator winding of generators are overheated by resistance loss. When calculation method of protection settings and logic for protection of generator asynchronization will be recommended, a distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome asynchronizing protection, this paper describes an improved backup protection coordination scheme using a new logic that will be suggested.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.125-130
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• 2007

Single-phase is used widely power of field of appliance because can use commercialized power directly without power transform. Specially, because condenser nu-drive style single-phase induction motor efficiency is excellent, and most suitable in embodiment as economical. It is established true that method by crossing self-discipline and method by revolving magnetic field are interpretation of net single-phase induction motor, but method to calculate electric motor inside proper move in existent theory or method is some complex. That arbor in the law of circuit constant that combine equivalent circuit law with numerical analysis law according to development of the latest computer or microprocessor is suggested and does the calculation processing fast and correct. In this paper, measurement wishes to present method that calculate after calculate digital measurement that measures correctly and measures impossible the first and the second leakage reactance and no-load test locked-rotor test, DC test and resistance measurement of stator winding in circuit parameter calculation program that is had for MatLab program individually in single-phase power.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.58-65
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• 2015

This paper deals with the generating characteristic analysis of permanent magnet linear generator (PMLG) with double-sided Halbach magnet array mover and three phases concentrated stator windings by using analytical method. On the basis of a magnetic vector potential and Maxwell's equations, governing equations are obtained, and magnetization modeling for Halbach magnet array is performed analytically by using the Fourier series. And then, we obtain electrical parameters such as back-EMF constant, resistance, and coil inductance based on magnetic field calculations. Finally, analytical results for generating performance are confirmed by comparing with finite element analysis results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.82-93
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• 2006

In this paper, filters are designed to reduce transients overvoltage in inverter fed high-voltage large-capacity induction motor drive system. Design issues for a LCR filter at the inverter output terminals to reduce the dv/dt of the inverter output pulse and a RC filter at the induction motor input terminals to match the characteristic impedance between cable and induction motor are examined in detail. These filters are modeled to be suitable to high-voltage large-capacity induction motor. The performance of the filter is evaluated through simulation using EMTP(ElectroMagnetic Transients Program). We presented filters that used high voltage large-capacity induction Motor on the basis of this. Effect of the filter is analyzed for variation of the cable length. Characteristics of filters are analyzed to reduce harmonic in voltage waveform of induction motor input terminal. The switching surge voltage became the major cause to occur the insulation failure by serious voltage stress in the stator winding of induction motor. Filter for to mitigate transients overvoltage presents a required component in drive system of high-voltage large-capacity induction motor. Also, proposed filters are proved through simulation using EMTP.