• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.73-73
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• 2011

In fact, asynchronous motors are used widely. Asynchronous motors which have large power (compared to the source supplies) is needed to start them in various methods. The theory of application reduced voltage to motor's stator or variable resistor fed rotor for the purpose of altering the motor's torque and power consumption characteristics is an idea that has existed for many years. These concepts have flourished mainly due to the need to limit torque and limited generator/power distribution capabilities. However, how can know exactly the time of switching steps with different types of motors as well as load characteristics is very difficult. This paper focuses on the design and development mathematical models of motor[1][2], load, ACB, asynchronous machine and then is implemented in SIMULINK in order to calculate this time, special on ships where power generation station is limited. The simulation results are both compared and discussed in detail so that it can apply to conclude the most suitable and applicable starting time for new system with various motors and load.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.232-234
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• 1999

A 30kVA superconducting generator (S.G.) has been designed, developed and successfully tested in KERI before the end of last year. The design is based on 2-dimensional electromagnetic field analysis of cylindrical coordinate. The field winding of rotor has been wound with superconducting wire of Nb-Ti alloy and tested after assembled with other rotor components. The stator has air-gap type armature windings which allow higher terminal voltage and more sinusoidal voltage waveform than conventional iron cored machines. Steady-state open & short-circuit test and lamp load test have been conducted also. The results of tests are given in this paper and compared with design quantities. Moreover the cooling scheme and characteristics of test system is included.

• Proceedings of the KIEE Conference
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• summer
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• pp.1118-1120
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• 2004

For the first time in Korea, a 100hp high Tc superconducting(HTS) motor has been designed, developed and successfully tested recently. The design was based on 2-dimensional electromagnetic field analysis of cylindrical coordinate. The field winding of rotor was wound with Bi-2223 tapes and tested after assembled with other rotor components. The stator had air-gap type armature windings which allow higher terminal voltage and more sinusoidal voltage waveform than conventional iron cored machines. Steady state open & short-circuit test and resistive load test were conducted also in generator mode. The fabrication and test results of this machine were discussed in this paper.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.559-568
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• 2014

Induction motors are critical components in industrial processes since their failure usually lead to an unexpected interruption at the industrial plant. The studies of induction motor behavior during abnormal conditions and the possibility to diagnose different types of faults have been a challenging topic for many electrical machine researchers. In this regard, an efficient and new method to detect the induction motor-fault may be the application of the Time Synchronous Averaging (TSA) to the stator current Park's Vector. The aim of this paper is to present a methodology by which defects in a three-phase wound rotor induction motor can be diagnosed. By exploiting the cyclostationarity characteristics of electrical signals, the TSA method is applied to the stator current Park's Vector, allowing the monitoring of the induction motor operation. Simulation and experimental results are presented in order to show the effectiveness of the proposed method. The obtained results are largely satisfactory, indicating a promising industrial application of the hybrid Park's Vector-TSA approach.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.96-101
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• 2023

In this work, an energy harvester (EH) on the rotating shaft has been proposed for a wireless sensor system (WSS) applications. The EH was designed and implemented to the shaft with a diameter of 20 cm to continuously power a wireless sensor system (WSS). The rotor has coils wound in pairs on seven U-shaped cores attached to the shaft. The stator consists of eight pairs of magnets attached to eight I-cores and they are fixed to an outer fixture. The generated power of the EH was investigated as function of the air gap between the rotor and stator, the number of turn of coils, and shaft speed. The fabricated EH produced power up to 2.87 W at 300 rpm and the 3 mm air gap.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.509-514
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• 2004

This paper introduces the modified slip energy recovery system in order to improve its power factor and to reduce harmonics of line current waveforms. Twelve pulse line commutated converter with the chopper type IGBT is applied where the chopper is applied across the DC terminal and the chopped DC is fed to the converter operating as an inverter and then passed through the wye-wye and delta-wye transformer circuit. This scheme leads to be able to adjust the speed of the motor by the duty cycle of the chopper operating in PWM mode. The fuzzy logic controller is also introduced to the modified slip energy recovery system for keeping the motor speed to be constant when the load varies. The experimental results in testing the 0.22 kW wound rotor induction motor from no-load condition to rated condition show the effectiveness of the proposed control scheme.

• Journal of Energy Engineering
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• v.9 no.4
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• pp.342-347
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• 2000

최근 산업계에서 급증하는 전력수요와 부하의 다양화는 전원의 안정도에 악영항을 미치고 있다. 이는 전압강하는 역률 저하 유/무효 전력의 변동을 초래하고 타부하에 영향을 미치게 되므로 이를 효과적으로 보상할 수 있는 종합적인 보상 시스템이 필요하다. 본 논문에서는 이러한 전력보상 시스템중의 하나로서 플라이휠을 장착한 권선형 유도기의 2차 여자방식을 제시한다. 본 시스템은 전동기 2차 여자방식을 이용함으로서 기존의 정지형 보상기에 비하여 인버터의 용량을 기존의 것보다 수배 감소시킬 수 있는 장점이 있으며 히스테리시스 전류제어기를 사용하여 직접 전류제어기를 사용하여 직접전류 제어방식을 이용하므로 기존의 시스템과 비교하여 PI제어기의 게인선정의 어려움을 극복하고 제어 알고리즘을 간략화 할 수 있는 특징을 가지고 있다. 또한 전력을 보상하기 위한 에너지 저장요소로 플라이휠의 관성에너지를 사용함으로서 기존의 배터리 방식의 무정전 전원공급장치를 대신하는 효과를 보인다. 설계된 시스템과 제어방식은 시뮬레시션을 통하여 입증하였다.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.55-59
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• 1991

This paper deals with the control stratege for the constant voltage, constant frequency(CVCF) generation of doubly-fed induction generator. As an induction machine is a nonlinear and multivariable machine, so, the control system is needed a very sophiticated control processes to meet a CVCF condition. In this paper, control system is constructed and tested using the suggested exitation equation. The test results show that the suggested equation and control system are very useful strategy for the CVCF control of induction generator.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.146-149
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• 1999

A 30kVA superconducting generator has been designed, developed and successfully tested recently. The design is based on 2-dimensional electromagnetic field analysis. The rotor has been wound with superconducting wire of Nb-Ti alloy. The stator has the air-gap type armature windings. Open-circuit test, short-circuit test and lamp load test have been conducted. The details of design program, design, machinebuilding, test results and conclusions are given in this paper.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.366-367
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• 2013

러시아를 포함한 동유럽 국가에서는 아직까지 상용전원으로 권선형 동기전동기를 구동시키는 산업현장이 많이 있으며, 최근 에너지 절감을 위해 대용량 고전압 권선형 동기전동기 구동용 H-브릿지 멀티레벨 인버터에 대한 수요가 증가하고 있다. 권선형 동기전동기의 일반 V/F 운전 시에 전동기 회전자의 속도가 완벽히 동기화되지 않아 저속영역에서 난조가 발생하여 출력토크가 진동하는 현상으로 운전에 어려움이 있으며, 저속 영역에서의 낮은 토크 출력으로 인하여 다양한 부하에 적용이 힘든 단점을 가지고 있다. 본 논문에서는 H-브릿지 멀티레벨 인버터의 권선형 동기전동기 구동 시 헌팅 억제 알고리즘을 추가하고 속도 지령에 보상함으로써 저속 영역의 속도/토크 헌팅 현상을 저감하는 센서리스 제어 방법을 제안하였다.