• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.739-740
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• 2006

According to the rapid growth of high speed and precise industry, the application of synchronous motor has been increased. In the application fields, the large synchronous motor is not a self-starting motor. The rotor is heavy and, from a dead stop, it is impossible to bring the rotor into magnetic lock with the rotating magnetic field for this reason, all synchronous motor have some kinds of starting device. A simple starter is another motor which brings the rotor up to approximately 96 percent of it synchronous speed. The starting motor is disconnected and the rotor locks in step with the rotating field. The more commony used starting method is to have the rotor to include a squirrel cage indution winding. This indution winding brings the rotor almost to synchronous speed as an induction motor. So, this paper describes excessive condition interpretation of a exciter circuit to prevent starting failure of large synchronous motor. the large synchronous motor needs safety of it in accordance with operating frequent start and stop. the operating Problem point of synchronous motor appears potential element damage of Exciter circuit because synchronous motor is caused synchronous separation. hence we eliminate it and improve starting toque.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.129-136
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• 2009

A motor cylinder is widely used as an apparatus for transportation of a small scale load. It is, however, difficult for only one motor cylinder to transfer a large scale load such as a weir. The large scale load is transferred by two motor cylinders which are mounted on right and left of load itself. In this case, the displacement difference generated between two motor cylinders, namely, the synchronous error has a bad influence on the transportation. In this study, a synchronous control system is designed to restrain synchronous error caused by skew disturbance. The control system is composed of two disturbance observers and one synchronous controller. Each disturbance observer is designed to restrain the skew disturbance. And the synchronous controller is designed to achieve stable and accurate synchronization. Finally, the simulation results show that the designed control system is effective for the skew disturbance which lead to synchronous error.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.57-61
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• 2008

A 1MW class HTS(High-Temperature Superconducting) synchronous motor has been developed. This motor was aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field windings of the developed motor is cooled by way of Neon thermosiphon mechanism and the stator coil is cooled by water through hollow copper conductor. This paper describes performance test results of our motor, which was conducted at steady state in generator mode and motor mode.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.411-419
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• 2008

SFC(Static Frequence Converter)system has come to be used as start up drive system for large synchronous motor in many industry applications. Many papers have been presented the control algorithm for pumped storage power generation using SFC system but they did not included about start up algorithm of SFC system for gas turbine. This paper presents the field weakening control algorithm for a large synchronous motor using output signal of anti-windup in PI current regulator and the results of experiment show that the proposed algorithm is proper and effective.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.450-457
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• 1998

Abstract - Linear Synchronous Motor has a large airgap comparing with rotary-type motor and especially, Permanent Magnet Linear Synchronous Motor(PM-LSM) which uses permanent magnet as a magnetic field, has a very large effective magnet airgap owing to permanent magnet structure. Accordingly, in case of 2-D analysis of the motor, the analysis error becomes large because leakage flux by which normal direction of the analysis region can not be considered, In this paper, the characteristic of PM-LSM for Maglev vehicle is analyzed exactly by 3-D Finite Element Method(3-D FEM). As the result, the effect of lateral-direction airgap magnetic flux density distribution on the analysis precision has been investigated and the motor characteristics according to primary motor parameter have been also made clear quantitatively. The accuracy of 3-D FEM has been confirmed by comparing the calculated results with the experimental results.

• Journal of Magnetics
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• v.21 no.3
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• pp.405-412
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• 2016

In general, surface mounted PM synchronous motors (SPMSMs) are mainly adopted as a driving motor for high-speed applications, because they have high efficiency and high power density. However, the SPMSMs have some weak points such as the increase of magnetic reluctance and additional losses as a consequence of using a non-magnetic sleeve. Especially, the magneto-motive force (MMF) in the air-gap of the SPMSMs is weakened due to the magnetically increased resistance. For that reason, a large amount of PM is consumed to meet the required MMF. Nevertheless, it cannot help using the sleeve in order to maintain the mechanical integrity of a rotor assembly in high-speed rotation. Thus, in this paper, a multi-layer interior PM synchronous motor (IPMSM) not using the sleeve is presented and designed as an alternative of a SPMSM. Both motors are evaluated by test results based on a variety of characteristics required for an air blower system of a fuel cell electric vehicle.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.367-370
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• 1997

Linear motors can drive a linear motion without intermediate gears, screws or crank shafts. Linear motors can successfully replace ball lead screw in machine tools because they have a high velocity, acceleration and good positioning accuracy. On the other hand, linear motors emit large amounts of heat and have low efficiency. In this paper, the thermal behavior of a synchronous linear motor with high velocity and force is analyzed. To improve the thermal characteristics of the linear motor, structure of linear motor and cooler is changed. Some effects of an integrated cooler, an U-cooler and a thermal symmetrical cooler are presented.

• Progress in Superconductivity and Cryogenics
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• v.11 no.2
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• pp.33-36
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• 2009

A 1 MW class HTS (High-Temperature Superconducting) synchronous motor has been developed. This motor is aimed to be utilized for industrial application such as large motors operating in large plants. The HTS field coil of the developed motor is cooled by way of neon thermo siphonmechanism and the stator (armature) coil is cooled by water through hollow copper conductor. This paper also describes evaluation of some electrical parameters from performance test results of our motor, which was conducted at steady state in generator mode and motor mode. Open and short circuit tests were conducted in generator mode while a 1.1 MW rated induction machine was rotating the HTS machine. Electrical parameters such as mutual inductance and synchronous inductance are deduced from these tests. Load test was done upto rating torque during motor mode and efficiency was measured at each load torque.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.84-89
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• 2005

This paper presents a control algorithm for a large salient-pole synchronous motor fed by a Load Commutated Inverter (LCI). Many papers have been presented in the past few years on the justification, design, and application of variable-speed drive. The focus of this paper is on high torque operation and the estimation of initial rotor position. The results of simulation indicate that it is possible to produce the maximum torque and estimate the initial rotor position.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.316-318
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• 2000

In this paper. we have simulated the transient stability of power system with motor loads. In study of power system stability, modelling of motors is required for the system with large concentrations of motors. Therefore the dynamics attributable to motors are usually the most significant aspects of dynamics characteristics of system loads. A synchronous motor is modelled as a dynamic load. We investigate the effect of synchronous motors of Kwang Yang network with three phase fault.