• 전기학회논문지P
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• 제54권3호
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• pp.134-140
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• 2005

Most of the loads in industrial power distribution systems are usually balanced and connected to three power systems. However, in the user power distribution systems, partial loads are single & three phase and unbalanced, generating voltage unbalance by the impedance mismatching. Voltage unbalance has detrimental effects on three-phase induction motors, including over heating, line-current unbalance, derating, torque pulsation, low efficiency, etc. This paper presents a scheme on operation states of a three-phase induction motor under the unbalanced voltages with harmonics components. Three-phase voltages applied to the stator winding of the studied induction motor are controlled by respectively adjusting not only fundamental but also harmonics components. Harmonic components at the voltage unbalanced factor(VUF) of the three-phase source voltages can then be examined the different values of VUF on machine's operation characteristics.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권6호
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• pp.372-379
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• 2004

Most of the loads in industrial power distribution systems are balanced and connected to three power systems. However, in the user power distribution systems, most of the loads are single ＆ three phase and unbalanced, generating voltage unbalance. Rotating machines operating on an unbalanced voltage will draw a highly unbalanced current. As a result, the three-phase currents may differ considerably, thus resulting in an increased temperature rise in the machine. This paper presents a scheme on steady states of a three-phase induction motor under unbalanced voltages. The three-phase voltages applied to the stator winding of the studied induction motor are controlled by respectively adjusting the magnitude and phase angle of each phase. The voltage unbalanced factor(VUF) of the three-phase source voltages can then be varied to examine the different values of VUF on machine's operation characteristics.

• 전기의세계
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• 제21권3호
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• pp.7-18
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• 1972

An analysis is made for the performance of twin stator single-phase induction machine having any movable asymmetrical angle of stator windings, with any symmetrical or asymmetrical magnetizing reactance and winding turn-ratio between two stators, provided that asymmetrical common squirrel cage rotor is utilized. This mechanism is a new type, which has the advantage of mading only not the performance prediction in applications as a single-phase electromagnetic driving mechanism but also the analysis prediction of single-phase induction motor with not in quadrature axis. The basis of the analyses are lead by Kron's primitive machine matrix and Morrill's double-revolving field concept. All the performances can be calculated from the test values and design details of the asymmetrical magnetizing reactance twin stator single-phase induction machine and verified by test. And its validity is still demonstrated to the pure twin stator single-phase induction machine.

• 전력전자학회논문지
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• 제7권4호
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• pp.322-331
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• 2002

본 논문은 단상 반파 PWM 정류기와 3상 2-leg 인버터를 결합한 단상-삼상 컨버터 회로에서 전원전압의 센서를 제거하여 3상 유도전동기를 저가형으로 구동하는 방법을 제안하고자 한다. 전원전압의 센서를 제거하기 위해 전원 전류의 실측치와 제어기 내의 모델전류가 일치하도록 관측기를 구성하여 전원전압을 추정한다. 본 논문에서 제안한 기법을 사용할 경우 스위칭 소자와 센서 수를 줄이면서 직류전압 일정제어, 입력전류의 정현제어 및 단위 역률 제어가 가능하고 VVVF 교류전압을 얻을 수 있다는 장점이 있다. 3[Hp]의 3상 유도전동기의 V/f 구동에 적용한 실험결과로 제시된 알고리즘의 타당성을 검증한다.

• Journal of Advanced Marine Engineering and Technology
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• 제17권3호
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• pp.70-79
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• 1993

The application of A.C. motor to servo system is rapidly increased according to the recent advance of power electronics and digital control techniques. The induction motor which has a simple structure and needs less maintenance is used in the industrial field for the variable speed and position control recently. In this paper, the current characteristic of the full-bridge resonant inverter is studied by comparing with the computer simulation and the laboratory experiment when the ratio of forced frequency to the natural frequency and the ratio of conduction time to the period at the given frequency is changed. And then, the full-bridge resonant inverter is applied to the speed control of single phase induction motor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권6호
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• pp.262-270
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• 2003

In this paper, the characteristics of single-phase line-start permanent magnet synchronous motor driven by constant voltage are analyzed on d-q axis vector diagram and compared with that of current controlled motor. The coupled method of symmetrical coordinates and d-q axis voltage equation are applied to the analysis method like the analysis of single-phase induction motor. From the result of the analysis, it is seen that motors driven by constant voltage source have effects on not only the amplitude of current and torque but also current and current phase angle, so overall characteristics such as power factor and load angle are affected by circuit parameters. For precise analysis and design of single-phase line-start synchronous motor, its characteristics should be analyzed on d-q axis vector plan in consideration of the variation of circuit parameters.

• 한국조명전기설비학회지:조명전기설비
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• 제9권5호
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• pp.41-50
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• 1995

Single-phase induction motors are widely used in many light duty applications, especially in home and office. many applications which use these motors require adjustable speed control continuously. In general, the speed control of single-phase induction motor is accomplished at a few discrete speeds by using tapped-windings, pole switching or gear. These techniques are inefficient and complicated. In this paper, Torque controller which adjusts a generating torque using phase difference between main winding voltage and auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage is proposed. The analysis includes the determination of the relationship between the auxiliary winding voltage phase angle and torque. Simulation results of the torque-speed characteristics using the controlled auxiliary winding supply are shown and discussed. and the drive is tested experimentally to verify the results of the theory by using a dynamometer.

• 전기학회논문지P
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• 제53권3호
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• pp.110-115
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• 2004

Most of the loads in industrial power distribution systems are balanced and connected to three power systems. However, in the user power distribution systems, most of the loads are single & three phase and unbalanced, generating voltage unbalance. This paper presents a scheme on operation states of a three-phase induction motor under unbalanced voltages. The three-phase voltages applied to the stator winding of the studied induction motor are controlled by respectively adjusting the magnitude and phase angle of each phase. The voltage unbalanced factor(VUF) of the three-phase source voltages can then be varied to examine the different values of VUF on machine's operation characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.3-5
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• 1998

This paper presents a speed control method for the capacitor run single-phase induction motor. The equivalent circuit of a capacitor motor is analyzed using the forward and the backward components, and simple circuit equations are obtained. Simulations for the speed control are performed by adjusting the voltage magnitude of the auxiliary winding.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.76-79
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• 1996

The most common for starting a single phase induction motor is to install a starting condenser and a centrifugal switch in series with the auxiliary winding. Though this method is simple, life of single phase induction motor is short because of malfunction of a starting condenser and a centrifugal switch and efficiency improvement has limitation. In this paper, the starting characteristics of SPIM is improved by sequence voltage control strategy of auxiliary winding in removing a starting condenser and a centrifugal switch. Finally, the excellent starting performance of SPIM is shown through simulation and experimental results.