• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.107-118
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• 1995

The characteristics of the current waveforms and 3$\Phi$ power waveforms of the variable speed 3$\Phi$ AC motor system driven by the single-pulse PWM investigated in this paper. The system is composed of a digital bridge inverter and low pass LC filter. It is confirmed that current waveforms and 3$\Phi$ power waveforms can be improved by utilizing the high order low pass LC filter than that of lower order through computer simulation. Also, we propose the low pass LC filter revised from the conventional LC filter.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.553-555
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• 1996

This paper concerns with a method to improve the current and power waveforms of the variable speed $3{\Phi}$ AC motor system driven by the single-pulse PWM, and the current waveforms and $3{\Phi}$ power waveforms are analyzed by FFT under various running conditions. By the performance analysis through the experiments, the following results have been obtained. AC source of pseudo sine waveform can be obtained from the modulated alternating square voltage by means of the well designed LC filter. It is confirmed that current waveforms and $3{\Phi}$ power waveforms can be improved by utilizing the high order low pass LC filter than that of lower order. Especially, current waveforms and $3{\Phi}$ power waveforms tan be much improved at low frequency domain. $3{\Phi}$ power waveforms have a smatter ripple and bigger power by utilizing the high order low pass LC filter than that of lower order. Also, the running condition of $3{\Phi}$ AC motor is good at low frequency domain.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.4
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• pp.79-91
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• 1995

Recently, the AC motor which has a simple structure and needs less maintenance has become to be used frequently as a servomotor for position control in the automatic control field. This paper concerns with a method to improve the current and power waveforms of an AC motor, and the current waveforms and 3$\phi$ power waveforms are analyzed by FFT under verious running conditions. The system is composed of a digital bridge inverter, low pass LC filter, and 3$\phi$ AC motor. Through the computer simulations and experiments, it is confirmed that current waveforms and $\phi$ power waveforms con by improved by utilizing the high order low pass LC filter than that of lower order.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.568-572
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• 1994

This paper presents equipment for charging and discharging with high power factor aid high efficiency. This equipment is consisted of $3{\phi}$SPWM AC/DC converter for improving input current waveform and input power factor, and bidirectional DC/DC converter for electric isolation in the DC link Part. Therefore, Input power factor and the total efficiency in the proposed system can be increased more than in the conventional phase-controlled thyristor Charging - Discharging System.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.371-375
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• 1995

This paper presents equipment for charging and discharging with high power factor and high efficiency. This equipment is consisted of $3{\phi}$ SPWM AC/DC converter for improving input current waveform and input power factor, and bidirectional DC/DC converter for electric isolation in the DC link Part. Therefore, Input power factor and the total efficiency in the proposed system can be increased more than in the conventional phase-controlled thyristor charging-discharging System.