• Title/Summary/Keyword: three phase

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A Study on Current and Torque Characteristics Of Three-Phase Induction Motor in Single-Phase Operation. (삼상유도전동기의 결상시 전류 및 회전력특성에 관한 연구)

  • 유춘식;노창주
    • Journal of Advanced Marine Engineering and Technology
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    • v.6 no.1
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    • pp.25-33
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    • 1982
  • The characteristics of the stator current and torque of a small three- phase squirrel cage induction motor and studied experimentally under the situation of a single-phase operation due to various causes. Through the experiments, the torque-slip and current-slip curve of single-phase circuit as well as three-phase circuit are obtained and the needed constants are determined. The stator current and torque are calculated by the current and torque equations derived by the unbalanced circuit theory. The numerical values obtained from the above methods are compared with the experimental values under the same conditions. The results of the study are summerized as follow; 1) The values computed by the unbalanced circuit theory generally come to approach the values recorded through experiments. 2) Near the rated load, speed drop is less than 1.2 per cent of the speed of three-phase induction motor and torque reduces less than 3 per cent of it of three-phase induction motor when three-phase induction motor is run under a single-phase. On the other hand, the stator current in a single-phase circuit is more than 1.9 times of it in three-phase circuit. 3) The stalling torque in a single-phase circuit is reduced to about 41 per cent of it in three-phase circuit while the corresponding slip is moved toward the synchroneous speed and the corresponding stator current is increased.

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Ozone Generation Synergy Effects of Three-Phase Voltage Apply Type Superposed Discharge Ozonizer (3상 전압인가형 중첩방전 오존발생기의 오존생성 상승효과)

  • Lee, Byeong-Jun;Lee, Sang-Geun;Song, Hyeon-Jik;Kim, Yeong-Hun;Park, Won-Ju;Lee, Gwang-Sik
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.8
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    • pp.468-476
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    • 2000
  • Nowadays, ozone is mainly utilized for water treatment and home equipments. Although the demand for ozone is increasing, the ozone yield of silent discharge type ozonizer is low. Therefore, it is expected to improve the energy efficiency and ozone yield of an ozonizer. In this paper, a new ozone generation system is proposed. The 60[Hz] three-phase voltage is applied to three-phase superposed discharge type ozonizer(3PSDO) which has three electrodes(central, internal and external electrodes). There is no discharge pause time when three-phase voltage is applied due to 120-degree phase difference of applied voltage. The synergy effect of the three-phase superposed discharge type ozonizer is investigated by comparing with the three sort of single-phase discharge type ozonizer(1PDO). So, three-phase superposed discharge type ozonizer is able to obtain high ozone yield, and optimize discharge space, because this can increase the discharge power at low applied voltage.

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Advanced Three-Phase PFC Power Converters with Three-Phase Diode Rectifier and Four-Switch Boost Chopper

  • Nishimura Kazunori;Hirachi Katsuya;Hiraki Eiji;Ahmed Nabil A.;Lee Hyun-Woo;Nakaoka Mutsuo
    • Journal of Power Electronics
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    • v.6 no.4
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    • pp.356-365
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    • 2006
  • This paper presents an improved three-phase PFC power rectifier with a three-phase diode rectifier cascaded four-switch boost converter. Its operating principle contains the operating principle of two conventional three-phase PFC power rectifiers: one switch boost converter type and a two switch boost converter type. The operating characteristics of the four switch boost converter type three-phase PFC power rectifier are evaluated from a practical point of view, being compared with one switch boost converter type and two switch boost converter topologies.

The effect of Harmonic Distortion Reduction on Three Phase Three level Inverter Using Neutral Point Control (3상 3레벨 인버터의 중성점 제어를 이용한 고조파 왜율 저감 효과)

  • Kim, Jeong Gyu;Yang, Oh
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.3
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    • pp.90-94
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    • 2018
  • In this paper, we applied a three-level T-type inverter with the one more voltage level than two-level inverter. However, the three-level T-type inverter has a systematic problem with voltage unbalances. So neutral point control is essential. Therefore, the voltage unbalance problem of the three - phase inverter was confirmed to be controlled within 5V using the neutral point control algorithm in charge and discharge mode. In addition, total harmonic distortion was reduced in three phases (u phase, v phase, w phase) when neutral point control was performed in charging mode and also in three phases (u phase, v phase, w phase) in discharge mode. In this paper suggests a neutral point control algorithm to solve the voltage unbalance of a three-level T-type inverter, and shows the improvement of the performance of the proposed algorithm through experiment.

Analysis on Fault Current Limiting Operation of Three-Phase Transformer Type SFCL Using Double Quench (이중퀜치를 이용한 삼상변압기형 한류기의 고장전류제한 동작 분석)

  • Han, Tae-Hee;Ko, Seok-Cheol;Lim, Sung-Hun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.2
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    • pp.184-189
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    • 2022
  • In this paper, the fault current limiting operations of three-phase transformer type superconducting fault current limiter (SFCL) using double quench, which consisted of E-I iron core with three legs wound by primary and secondary windings and two superconducting modules (SCMs), were analyzed according to three-phase ground fault types. To verify the effective operation of the three-phase transformer type SFCL using double quench, the test circuit for three-phase ground faults was constructed, and the fault current tests were carried out. Through analysis on the fault current test results, the different fault current limiting characteristics of three-phase transformer type SFCL using double quench from three-phase transformer type SFCL using three SCMs were discussed.

A Study on the Uninterruptible Power Supply on the Open Phase of Three-phase Motor (3상 전동기 결상시 무정전 전원공급장치에 대한 연구)

  • Shin, Hyr-Young;Choi, Hong-Kyoo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.9
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    • pp.1317-1320
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    • 2014
  • In case of using three-phase induction motor in three-phase power system, if he deficiency happens in phase among three-phase, the motor will drive in an open phase state. As to the motor, the continuing operation is possible then, but the phenomenon that the power supply stops happening by the result of the overload electricity order on the healthy phase of two phases with a damage and activating the circuit breaker. Consequently, in order to overcome this problem in treatise accordingly. I propose an uninterruptible power supply which is able to prevent that the over current on the health phase through the restoration that in case happening open phase on the power line when driving the motor. Also, it is possible to supply power consecutively without interruption of electric power and we proved the performance and reliability through an experiment.

Single Phase to 3 Phase Conversion Using Cyclo-Converter (Cycloconverter를 이용한 단상-3상 변환에 관한 연구)

  • 박민호;전상대
    • 전기의세계
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    • v.28 no.3
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    • pp.51-56
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    • 1979
  • The purpose of this paper is to study the conversion of single phase to three phase. In the proceeding of phase conversion, it is very convinence to convert two-phase from single phase using cycloconverter before and then two to three phase by scott connection transformer. There are also systematized zero-crossing, mono vibrator and ring counter circuit for the gate trigger circuits of cycloconverter. The wave forms of three phase by experimental results are analyzed and discussed the relation of phase difference among them.

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Generalized Circulating Current Control Method in Parallel Three-Phase Boost Converters (병렬 삼상 부스트 컨버터에서 일반화된 순환전류 제어 방법)

  • Lim, Chang-Soon;Lee, Kui-Jun;Kim, Rae-Young;Hyun, Dong-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.16 no.3
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    • pp.250-257
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    • 2011
  • This paper analyzes characteristic of the three-phase coupled inductor connected to ac source to effectively mitigate the high-frequency circulating current generated in parallel three-phase boost converters. The three-phase coupled inductor analysis presented in this paper uses the three-phase coupled inductor structure and voltage equations. Based on this analysis, the three-phase coupled inductor is added to the conventional low-frequency averaged model. As a result, the novel averaged model which can reduce the low and high-frequency circulating current simultaneously is developed. Using the zero-sequence component of the novel averaged model, each total inductance to the circulating current of the three-phase coupled inductor and line inductor can be obtained. Simulation and experiment results verify the usefulness of three-phase coupled inductor in parallel three-phase boost converters.

Modeling and Analysis of Three Phase PWM Converter (3상 PWM 컨버터의 모델링 및 해석)

  • 조국춘;박채운;최종묵
    • Proceedings of the KSR Conference
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    • 1999.05a
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    • pp.328-335
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    • 1999
  • Three phase full bridge rectifier has been used to obtain dc voltage from three phase ac voltage source. The rectifier system has drawbacks that power factor is low and power flow is unidirectional. Therefore, when dc voltage increases due to regeneration of power the dynamic resister for dissipation of regeneration power must be installed. But three phase PWM converter can be controlled to operate with unity power factor and bidirectional power flow. Therefore when the PWM converter is used as do supply system, the dissipating resistor is not necessary. On this thesis, in order to design a controller having good performance, the hee phase PWM converter is completely modeled by using circuit DQ-transformation and thus a general and simple instructive equivalent circuit is obtained; the inductor set becomes a second order gyrator-coupled system and three phase inverter becomes a transformer as well. Under given phase angle(${\alpha}$) and modulation index(MI) of the three phase inverter, the dc and ac characteristics are obtained by analysis of the transformed equivalent circuit The validity of the equivalent circuit is confirmed through PSPICE simulation. And based on the dc and ac characteristics a controller with unity power factor is proposed.

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Novel Converter Topology for a Three Phase to Three Phase PWM Rectifier/Inverter System (비용절감형 컨버터 구조를 갖는 3상-3상 PWM 정류기/인버터 시스템)

  • Kim, Gi-Taek;Park, Tae-Yeol;Lee, Hae-Chun
    • Journal of Industrial Technology
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    • v.18
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    • pp.323-328
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    • 1998
  • A current controlled VSI-PWM rectifier and inverter with capacitor dc link is regarded as one of the most promising structures for three-phase to three-phase to three-phase power conversion. This type of converter normally requires twelve switches for a rectifier and inverter composed of self turn-off switch such as a bi-polar transistor or IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase converter for ac motor drives is proposed. The proposed converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using generalized modulation theory and experimental results for steady state and dynamic behavior are presented to verify the developed model.

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