• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.510-516
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• 1999

In this paper, a new high-powerfactor control method for boost-type rectifier is proposed, which removes the necessity of input current sensing. This method generates a sinewave duty template only from the line voltage waveform and rectifier output, and reduces reactive power remarkably utilizing three compensation coefficients which are determined through experiments. These compensations make the input current to be in phase with the input voltage all over the load range. A prototype boost-type rectifier is designed and experimental results are presented.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1969-1972
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• 1998

Harmonic analysis is important for PWM rectifiers with high powerfactor. This paper describes the harmonic analysis of input current in high powerfactor boost-type rectifier. The magnitudes of the harmonics are obtained through the current wave from analysis and the effect of source reactance is also analyzed.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.702-704
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• 2001

This paper investigates efficiency and power factor of Switched Reluctance Motor (SRM) using Finite Element Method considered driving circuit. The efficiency and power factor are calculated in Input terminal and Output terminal respectively. When calculating power factor, apparent power is obtained by effective voltage and current because SRM is operated by switching of driving circuit. Efficiency is calculated by mechanical output and active power. Finally, the characteristics of efficiency and power factor in three proposed models are compared due to the switching pattern.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.395-397
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• 1999

This paper presents a method of improving the power factor and the waveform of A.C line currents and the out waveforms of AC to DC fully bridge converter systems which is achieved by connecting converters in series and parallel. The results of simulation show that the power factor and the source voltage and current waveforms are improved by the method of connecting converter in series, and the controlled input voltage and current waveform using a current limit controller.

• 전기의세계
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• v.27 no.5
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• pp.69-75
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• 1978

3 phase induction motor applied in the method of connecting it directly across the line needs large current when it starts. At that time, leakage magnetic pathes of interior of the motor are severely saturated and leakage reactances are decreased because of saturation. Consequently, increased current and raised powerfactor yield increase of starting torque. The author, noticing those phenomena, derived experimentally the raion of decreasing leakage reactance from the fact that when voltage applied to motor is increased under locked condition the magnitude of current and phase angle are varied, and determined tha equations of starting current and starting torque, considering the decrease of leakage reactance by the large starting current. The author calculated the characteristics of Current-Time and Speed-Time with the determined equation at specific load conditions, and compared the values obtained from above calculations with those from circle diagram's method and the practically recorded values at same load conditions. Therefore, the authos got a confidience that the results of the derived theory coincide with the practically measured values more well than circle diagram's results and circle diagram's equation should be modified in order to analize the starting status of a induction motor.