• Title/Summary/Keyword: Motor-generator

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Analysis for the Operating Characteristics when the Induction Motor is Used as a Generator (유도전동기를 발전기로 사용시 동작 특성 해석)

  • Kim, Jong-Gyeum
    • New & Renewable Energy
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    • v.10 no.2
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    • pp.5-11
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    • 2014
  • Squirrel cage induction motor is the main driving system of industrial field and familiar with its use in a large variety of applications. The structure and operating characteristics of induction generator is almost identical to induction motor, but the induction generator part is used restrictively from hydropower power and wind power development etc. Recently induction generator is commonly used for micro & small hydro power applications due to its simplicity, reliability, low cost and robustness. Input and output of induction motor has turned against at the induction generator operation. Rotation speed of induction generator is small faster than synchronous speed of induction motor. As output of induction machines increases with the increasement of speed, so loss is same. Actually, generator efficiency is lower than motor at this condition. If induction generator is connected with mechanical load such as increaser, total efficiency is decreased. Consequently the quality in compliance with an induction motor parameter applying like that in the generator is a possibility of having the error of some. In this paper, we analyzed that input, output, torque and efficiency of induction machine is different from each other above and below synchronous speed.

Design of a Small-Scale Motor-Generator System for a Large Wind Turbine (대형 풍력발전기용 소형 모터-발전기 시스템 설계)

  • Lim, Chae Wook
    • The KSFM Journal of Fluid Machinery
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    • v.20 no.1
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    • pp.48-52
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    • 2017
  • Small-scale motor-generator sets have been used in laboratories for verification of real large wind turbines whose rated power are more than 1 MW. In this paper, a result of designing a small-scale motor-generator system, which is composed of motor, gear box, flywheel, and generator, is presented in the aspect of speed response. Design objective is to make a small-scale motor-generator system have the same time constant and optimal tip speed ratio region as a real MW wind turbine. A small-scale 3.5 kW motor-generator system for emulating response of a 2 MW wind turbine is considered and designed.

Characteristics Analysis for Motor or Generator Operating of Induction Machine with Deep or Double Cage Rotor (심구 또는 이중 농형 회전자를 가진 유도기의 전동 또는 발전 운전시 특성 해석)

  • Kim, Jong-Gyeum
    • New & Renewable Energy
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    • v.10 no.4
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    • pp.3-8
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    • 2014
  • Both of induction generator and synchronous generator is available in the hydroelectric power plant. If the output of the power station is large, the synchronous generator is mainly used but when its output is low, the induction generator is often used. If the output capacity is small, there is a case in which induction motor is used as a generator. Torque at rated operation and start of the induction motor is different depending on the shape of the rotor. Small and medium-sized squirrel-cage induction motor is used primarily double cage rotor or deep bar. In this study, we attempt to interpret characteristics for double cage rotor or deep bar that occur when operating in the induction generator based on the parameters that have been designed and manufactured as an induction motor.

Study on Emergency Generator Capacity Selection(PG3) in the Chemical Plant (화학 플랜트에서의 비상발전기 용량선정 방안(PG3)에 관한 연구)

  • Lee, Seung-Jae;Jo, Man-Young;Kim, Se-Yong;Kim, Eun-Tae;Kang, Byoung-Wook;Park, Han-Min;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.12
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    • pp.55-60
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    • 2015
  • PG and RG methods are widely known method for calculating the capacity of the emergency generator in construction electrical installation. PG and RG methods are mainly used as a saving a life, fire protection, fire fighting in construction. Because no long distance between the emergency generator and electric motor feeder, the relatively small motor power in construction electrical installation, the capacity of generator in PG and RG methods are little problem of voltage and reactive power of generator. However in many cases the application of the PG and RG method is difficult in the Chemical Plant because it is long distance between the generator and the motor Feeder and motor capacity is very large. Motor starting power factor is about 0.2 lagging power factor and motor starting current is about 6times during motor staring. Also Most of the staring current component is a reactive power component. therefore, it is many cases that lack of reactive power and excess of allowable voltage drop limit and After selection of emergency diesel generator, problems happen during motor starting. Therefore, to be selection of effective emergency generator, active generator power, reactive power and the required reactive power during large motor starting should be considered in chemical plant. It is also required of the verification process through simulation because hand calculation is very difficult considering study cases.

Characteristics Analysis of Induction Generator with a Change in Rotor Speed (회전속도 변화에 따른 유도발전기의 특성 해석)

  • Kim, Jong-Gyeum;Park, Young-Jeen;Kim, Il-Jung;Kim, Young-Kuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2225-2229
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    • 2011
  • Squirrel cage induction motor is the main driving system of industrial field and familiar with its use in a large variety of applications. However, many engineer are unfamiliar with the induction generator, even though no difference exists between both machines except for the mode of operation. But an induction generator is commonly used for micro & small hydro power applications due to its simplicity, reliability, low cost and robustness. Input and output of induction motor has turned against at the induction generator operation. Rotation speed of induction generator is small faster than induction motor. As output of induction machines increases with the increasement of speed, so loss is same. Actually, generator efficiency is lower than motor at this condition. If induction generator is connected with mechanical load, total efficiency is decreased. In this paper, we analyzed that input, output, torque and efficiency is different from each other above and below synchronous speed.

A Study on the Starter Control of the Turbo Generator (터보 제너레이터의 시동기 제어에 관한 연구)

  • 박승엽;노민식
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.3
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    • pp.286-293
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    • 2004
  • This paper presents the result of a study on the starter control for a turbo generator. Because a starter in gear box type turbo-generator system is composed of gearbox and brush DC motor, it should be replaced with High Speed Generator(HSG)) in HSG type Turbo-generator. There-ore, it is necessary to design a new starting algorithm and starter. In gearbox type system, brush DC motor is rotated to the designed speed using low voltage-high current battery power. After brush DC motor speed is increased to several times by gearbox, gas turbine engine can be rotated to designed starting speed. If we implement a starter with High Speed Generator(HSG), it is necessary to drive high-speed generator to high-speed motor. High-speed generator with permanent magnet on rotor has a low leakage inductance fur driving high-speed rotation, and it is necessary high DC link voltage for inverter when High-speed generator is driven to high speed. This paper presents result of development of the boost converter for converting high voltage DC from low battery voltage and design of the inverter for controlling a high frequency current to be injected to motor winding. Also, we show performance of the designed starter by driving the turbo generator.

Analysis of D-C Shunt Motor Characteristics, driving D-C Series Generator (직통직권 발전기에 의한 직통분권 전동기의 특성해석)

  • 이승원;한송엽
    • 전기의세계
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    • v.16 no.1
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    • pp.7-13
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    • 1967
  • There are many kinds of motors operating by rated voltage which is constant. In this paper, the characteristics of separately excited direct current motor is analyzed when its terminal voltage is varied as its load current. As for this source, direct current generator of a series field is used, and it is driven at constant speed by a primemover. The induced voltage of the generator is propotional to its load current but it saturates as its load current is large. The charateristics of motor is studied by analog computer because of the nonlinearity of generator. The results are as follows: (1) The load current and the rotor speed of motor increase as the load of motor increases. But the speed of rotor decreases for the influence of the saturation of the iron of generator field when its load current is large. (2) Decreasing the inertia of motor and increasing the inductance of the armature circuit improve the stability of motor and the region of stable state. (3) By changing the field current of the motor, the speed and the direction of rotor can be controlled in wide range.

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Development of Central Monitoring System for Insulation Diagnosis of High-Voltage Generator/Motor Stator Windings (고압 회전기 고정자 권선의 절연진단을 위한 중앙 집중 감시 시스템 개발)

  • Shin, Byoung-Chol;Yoon, Dae-Hee;Hwang, Don-Ha;Kim, Yong-Joo;Ju, Young-Ho;Kim, Jeong-Woo
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1906-1908
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    • 2000
  • The central monitoring system with on-line diagnosis of high-voltage generator/motor stator insulation is developed. The system is capable of remote diagnosis and monitoring partial discharges of high-voltage generator/motor stator insulation. GOMS(Generator On-line Monitoring System) with maximum of 9 input channels can measure and analyze the status of high-voltage motor stator insulation by on-line. The measured and analysis data are brought to the central monitoring system via modem to build database. The central monitoring system can diagnose and monitor the insulation status of several high-voltage generator/motor at any time. The insulation status of those machines can be enhanced by the database on partial discharges.

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Structural Analysis considering Electromagnetic Force on Motor/Generator for Flywheel Energy Storage System (전자기력을 고려한 플라이휠 에너지 저장시스템용 전동발전기 구조해석)

  • Ko, W.S.;Ryu, D.W.;Oh, S.D.;Seong, Tae-Hyeon;Han, Sang-Cheol;Han, Yeong-Hui
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.485-490
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    • 2004
  • Flywheel Energy Storage System(FESS) consists of a high speed flywheel with an integral motor/generator suspended on non contact bearings and in an evacuated housing. Permanent magnet machines as the FESS motor/generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper, the structural design method of rotor retainer for a high speed motor/generator are presented.

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Analysis and Design of high-efficiency Permanent Magnet Synchronous Motor/Generator for Renewable Energy Application (신재생 에너지 적용을 위한 고효율 영구자석 동기 전동/발전기의 해석 및 설계)

  • You, Dae-Joon;Kim, Il-Jung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.5
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    • pp.955-964
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    • 2011
  • In renewable energy system such as flywheel energy storage system, wind power and solar power, the motor/generator is the important key for offering the electric energy to the electric loads. For example, the heavy and large flywheel is rotated by electromagnetic torque of pemanent magnet synchronous motor (PMSM) and, in case of a breakdown of electric current, the PMSM used as generator supplies electric energy for the various electric utilities using mechanical rotation energy of the flywheel. Thus, design of a motor/generator should be performed in effort to reduce cogging torque and electromagnetic loss for high efficiency. In our paper, a slotless permanent magnet synchronous motor/generator (SPMSM/G) with output power 15kW at the rotor speed 18000rpm is designed from electromagnetic analysis and dynamic performance analysis. In analytical approach, design parameters such as back electro-motive force (back EMF), inductance and electromagnetic torque are derived from analytical method which is one of the electromagnetic analysis method. And using the design parameters, this paper deal with system design considering the driving characteristics and electric load in required power. Finally, the analytical results are verified by the experiment and finite element method (FEM).