• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.364-371
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• 2007

This paper deals with filter design for utility-interactive voltage-sourced PWM inverters built by single-phase half-bridge topology. By analyzing the relation between utility voltage and the ac output voltage of single-phase half-bridge inverters, the instantaneous voltage applied on the filter inductor is deduced qualitatively and quantitatively. Moreover, switching ripple current through the filter inductor is calculated from the filter inductor voltage. Based on the above mentioned analysis, filter design method is proposed by evaluating the percentage of the switching ripple current against the rated fundamental current. Proposed filter design method is verified by simulation and experiment.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.161-167
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• 1999

3-input neuron-MOSFET inverters and 3-bit D/A converters using enhancement type device have been designed and fabricated by using standard 2-poly CMOS process. The voltage transfer curve and the noise margin of neuron-MOSFET inverters have been measured and characterized as the same method in normal CMOS inverters. From the theoretical calculation of the effects of coupling ratio on the voltage transfer curve and noise margin, we set up the design guideline for the gate oxide thickness and input gate layout in neuron-MOSFET inverters. BT using one of input gates as a control gate, we can design and fabricate the neuron-MOSFET D/A converter without offset voltage.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.1
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• pp.53-60
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• 2001

In many applications of power electronics, high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. And the resonant inverters have to control the output frequency for the reliable operation under the variable load conditions. In this paper, a new switching scheme is proposed as a PWM control of resonant inverters. With the proposed method, it can be obtained that optimum resonant frequency and unity output displacement factor under the variable resonant frequency adaptively. The detail algorithm or the proposed PWM switching scheme and its output characteristics are discussed. And the veridity of the proposed method is confirmed with the experimental results.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.500-504
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• 1997

Current source inverter drives of auto sequentially commutated type are very popular in high power applications, because of simple power circuit configuration with four quadrant operation. But the six-step current output create harmonic problems and the input power factor of such a drive is not always good. In this respect pulse width modulated drives using gate turn off thyristors ( GTO ) are finding application, especially in traction drives. However the switching and snubber loses of a GTO do not permit the inverter switching frequency go beyond a few hundred hertz.This will again introduce low frequency harmonic problems. Multi level inverters of the 3-level and 5-level can be considered as an alternative to overcome the low switching frequency harmonic problem of the 2-level GTO inverters. But with multi level inverters the complexity of the power circuit increases. In this paper a combination of multi level ( 2-level and 3-level ) inverters and multi phase induction motor ( 3-phase and 6-phase) configurations are presented for high power VSI drives for traction applications with reduced inverter switching frequency requirements coupled with reduced voltage rating for the power switch.

• Journal of Power Electronics
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• v.11 no.6
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• pp.837-845
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• 2011

This paper proposes phase current reconstruction techniques for two-phase two-leg and two-phase four-leg inverters using a single current sensor. In the proposed methods, one phase current is sampled simultaneously with a particular branch current by using only one current sensor, and then current reconstruction algorithms are applied to extract the information on two phase currents from the sensor output. The sampled current information is periodically updated at the peak and the valley of the triangular carrier waveform in each switching cycle of pulse-width modulation (PWM). The voltage vector spaces where the phase currents can be reconstructed are evaluated. Compared to the existing method using two individual current sensors in two phases, the proposed schemes can save implementation cost since it is possible to remove one current sensor. In addition, the proposed methods are free from gain discrepancy issues between two current sensors. Simulations and experiments show excellent current reconstruction performance of the proposed methods.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.4
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• pp.346-353
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• 2007

This paper deals with filter design for utility-interactive voltage-sourced PWM inverters built by single-phase full-bridge topology By analyzing the relation between utility voltage and the ac output voltage of single-phase half-bridge inverters, the instantaneous voltage applied on the filter inductor is deduced qualitatively and quantitatively. Moreover, switching ripple current through the filter inductor is calculated from the filter inductor voltage. Based on the above mentioned analysis, filter design method is proposed by evaluating the percentage of the switching ripple current against the rated fundamental current. Proposed filter design method is verified by simulation and experiment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.139-144
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• 2023

In order to obtain the maximum characteristics of motors such as torque and efficiency, all motors basically use universal inverters designed for each motor's characteristics. However, if you look at the recent research results, you can see cases of SRM(Switched Reluctance Motor) driving studies using 6-switch inverters, which are BLDC(Brushless DC Motor) universal inverters, and research cases of driving 3-phase BLDC motors using 4-switch inverters. Therefore, it is possible to search for research methods by approaching various methods of driving and control that can drive each motor apart from the existing universal inverter. In line with this research trend, in this paper, a C-dump type converter, which is an SRM drive converter, was applied as a drive driver for a BLDC motor, and its characteristics and possibilities were studied.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.487-488
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• 2016

In this paper, a new active circuit for common-mode voltage (CMV) cancellation in three-level NPC (neutral-point clamped) inverters is proposed, which can avoid the saturation of the common-mode transformer (CMT). The proposed circuit utilizes an additional three-level leg to produce the compensating CMV of the NPC inverters, which eliminates the CMV of the inverter through the CMT.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.355-359
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• 2000

This paper deal with the harmonic reduction technique in three-phase square-wave inverter system formed by single-phase inverter. To reduce the harmonics six single-phase inverters are used for forming multi-phase inverter and zig-zag connected output transformer for eliminating the harmonic 6(2k-1)$\pm$1 orders. And an ac filter is furnished at output side. Computer simulations show that the THD of the output voltage can be reduced immensely.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.17-20
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• 2000

Usually, in many applications, high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. In this paper, a new switching scheme is proposed as a PWM control method. With the proposed method, it can be obtained that unity output displacement factor under the variable resonant frequency. The detail algorithm of the proposed PWM switching scheme and its charicteristics are discussed. And the validity of the proposed method is confirmed with the experimental results.