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A Study on the Voltage Drop of Induction Generator along the Rotor Shape (회전자 형상에 따른 유도발전기 전압강하에 대한 연구)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.2
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    • pp.62-66
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    • 2015
  • Induction generator is easy to durability and maintenance than the synchronous generator. So, recently Induction generator has been widely applied to small-scale hydroelectric power plant. When the rotor is operating faster than synchronous speed, induction machine can generate electric power. Induction generator has a large inrush currents, such as the starting current of the induction motor. Induction motor has been designed a variety of rotor shape in order to reduce starting current. Since the occurrence of high inrush current cause a voltage drop to the system, it will need to reduce possible. Because the starting current of the squirrel-cage induction motor varies in accordance with the rotor shape, it is necessary to analyze the magnitude of inrush current in order to apply to the generator. In this study, we analyzed the inrush current and the voltage drop caused in accordance with the rotor shape of 1500kw induction generator.

Characteristics for Current and Power of Induction Motor by Load Variation (부하변동에 따른 유도전동기 전류와 전력 특성)

  • Kim, Jong-Gyeum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.8
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    • pp.82-87
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    • 2011
  • Induction motor is most widely used as the driving power in the industrial site. Induction motor current is composed of two parts, magnetizing current and load current. Load current uses energy what is doing the work. Load current varies with load variance but magnetizing current is constant, regardless of load variation. Magnetizing current needs for establishing the rotating magnetic field of induction motor and lags behind the voltage. Generally capacitor is used for power-factor compensation of inductive load. Self-excitation occurs when the capacitive reactive current from the capacitor is greater than the magnetizing current of the induction motor. When this occurs, excessive voltages can result on the terminals of the motor. This excessive voltage can cause insulation degradation and ultimately result in motor insulation failure. In this paper, we analyzed that how the magnetizing current and condenser current is operating at the allowable limit by the load variation. Condenser current is below allowable limit of magnetizing current but magnetizing current is above allowable limit at the lower load operation condition.

Steady-State Current Characteristics for Squirrel Cage Induction Motor according to Design Variables of Rotor Bars using Time Difference Finite Element Analysis

  • Kim, Young Sun
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.104-108
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    • 2017
  • Induction motors have wide applicability in many fields, both in industrial sectors and households, for their advantages of a high efficiency and robust structure. The introduction of power-source-containing harmonics into the induction motor winding lowers its efficiency and increases its temperature, greatly affecting its operation characteristics. In this study, we performed an electromagnetic field analysis using the time-difference finite-element method with the purpose of analyzing the steady-state current characteristics of an induction motor. Additionally, we calculated the steady-state current with a method combining an electromagnetic field equation and a circuit equation. In the electromagnetic field analysis, the nonlinearity was taken into account using the Newton-Raphson method, and a backward time-difference method was employed for the time derivative term. Then, we compared the steady-state current of the induction motor obtained by calculation with the experimentally measured values, thus validating the proposed algorithm. Furthermore, we analyzed the impacts of the shape and material of the rotor conductor bar of the induction motor on the steady-state current of the main winding.

Compensation of the rotor time constant of induction motor using current error feedback (전류오차 궤환을 이용한 유도전동기 회전자 시정수 보상)

  • 김승민;이무영;권우현
    • 제어로봇시스템학회:학술대회논문집
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    • pp.195-198
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    • 1997
  • This paper proposes the effective compensation method of the rotor time constant of induction motor. An indirect vector control method is highly dependent on the motor parameters. To solve the problem of performance degradation due to parameter variation in an indirect vector control of induction motor, we compensate the rotor time constant by current error feedback. The proposed method is a simple on-line rotor time constant compensation method using the information from terminal voltages and currents. As the current error, difference between current command and estimated current, approaches to zero, the value of rotor time constant in an indirect vector controller follows the real value of induction motor. This scheme is valid transient region as well as steady state region regardless of low or high speed. This method is verified by computer simulation. For this, we constructed the simulation model of induction motor, indirect vector controller and current regulated PWM (CRPWM) voltage source inverter (VSI) using SIMULINK in MATLAB.

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A Research on Self-excitation and Power Factor Compensation of Induction Motor (유도전동기의 자기여자 및 역률보상에 대한 연구)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.4
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    • pp.236-240
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    • 2014
  • Induction motor requires a rotating magnetic for rotation. Current required to generate the rotating magnetic field is magnetizing current. This magnetizing current is associated with the reactive power. This reactive power must be supplied from source side. Therefore, the power factor of the induction motor is low. So, the capacitor is installed on the motor terminals to compensate for the low power factor. Power supply company has recommended to maintain a high power factor to the customer. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. So it is necessary to calculate the optimal capacity capacitor current does not exceed the magnetizing current. In this study, we first compute the no-load current and the reactive power of the induction motor and then calculates the limit of the maximum power factor without causing self-excitation.

Speed control induction motor (속도제어형 유도전동기)

  • 오상세;박창엽
    • 전기의세계
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    • v.17 no.1
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    • pp.6-10
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    • 1968
  • To control of the speed of induction Motor, a variable frequency power supply is needed. But this New type induction Motor Constitute stator and Rotor with New principle, its speed can be easily and widely Controlled by changing phase of the stator, and start at low current than rating without starter. Also, its no load current is same as shart current, and speed increase in proportion to current. On this points this induction Motor for speed control is different from induction Motor using Now.

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Soft Start-up Characteristics Analysis of Squirrel Cage Induction Generator (농형 유도 발전기의 소프트 기동 특성 해석)

  • Kim, Jong-Gyeum;Park, Young-Jeen
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.1
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    • pp.103-107
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    • 2016
  • In general, the voltage stability of induction generator is lower than synchronous generator. Induction generator has a number of advantages over the synchronous generator on the side of price and maintenance. So Induction generator has been applied to the small hydroelectric power of low output. Induction generator usually generates a high current during grid connection. The high current that occurs during grid connection can cause a voltage drop in the system. In order to increase the supply of the induction generator, it is necessary to propose a method of reducing high current. This paper proposes some method of the soft start to reduce voltage drop caused by the large starting current. soft-start method has high voltage drop effect than direct start method, control of firing angle can be increased the voltage drop effect.

Novel Electromagnetic Induction Eddy Current DPH based Continuous Pipeline Fluid Heating using Soft Switching PWM High Frequency Inverter

  • Nam, Jing-Rak
    • Journal of information and communication convergence engineering
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    • v.6 no.3
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    • pp.305-309
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    • 2008
  • This paper presents an innovative prototype of a new conceptual electromagnetic induction eddy current based fluid heating appliance using voltage-fed quasi resonant zero voltage soft switching PWM high-frequency inverter using IGBTs, which can operate at a constant frequency variable power regulation scheme. The promising simple high efficient low noise inverter type electromagnetic induction eddy current based pipeline fluid heating appliance is proposed for saturated steam generator, superheated steam generator, hot water and hot air producer, metal catalyst heating for exhaust gas cleaning in engine. Under these technological backgrounds, a novel electromagnetic induction eddy current Dual Packs Heater(DPH) based pipeline fluid heating incorporates thin metal layer type package for continuous fluid heating appliances applying two types of voltage-fed quasi load resonant ZVS-PWM high frequency inverter. The unique features of a novel electromagnetic induction eddy current DPH based continuous pipeline fluid heating appliance is illustrated on the basis of simulation and discussed for the steady state operating characteristics and experimental results.

Starting Characterization of Induction Motor using Reactor Tap Change (리액터 탭 절환에 의한 유도전동기의 기동 특성)

  • Kim, Jong-Gyeum
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.1
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    • pp.24-28
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    • 2014
  • An induction motor is most widely used to obtain driving force in the industrial field. The induction motor is generated a high current at starting. A starting current is often more than five times of rated current. A high starting current can cause problems such as voltage drop in the power system. In order to solve these problems, a reactor starting method has been widely applied in a large motor capacity. There are differences in the operating characteristics of induction motor corresponding the switching time of reactor tap. In this study, I analyzed that current, torque, power of induction motor are different from changing time and tap setting values of reactor tap.

Current Control of Induction Motor using Neural Networks (신경 회로망을 이용한 유도 전동기의 전류제어)

  • Park, Young-Soo;Seo, Ho-Joon;Kim, Seong-Hwan;Seo, Sam-Jun;Kim, Dong-Slk;Park, Gwi-Tae
    • Proceedings of the KIEE Conference
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    • pp.66-68
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    • 1997
  • In this paper, our interest is the identification and control of nonlinear dynamic plant, induction motor, by using neural networks. We usually use vector control in the induction motor such as in the DC motor. When we go over the inputs of voltage source invertor, we can find that torque current and flux current couple each other in the induction motor. Before putting control inputs in the system, we should remove the coupling terms which we already know from them. But we should consider that cross coupling terms have time-varying variables. In this paper, we identified the parameter of induction motor by using neural networks and designed the controller with identified parameters. Through this procedure we obtained compensated inputs which are decoupled each other. Using induction motor currents control, we can make the d axis current hold constant value and control the q axis current at the same time.

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