• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.8
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• pp.509-513
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• 2000

This paper deals with the parallel operation of space vector PWM for large capacity inverter system. To enlarge the capacity of inverter system and to reduce the current ripples on inverter output side, two or more inverters are operated in parallel. In this paper, a new parallel operation strategy which minimizes the harmonic distortion of the output stage is described. The proposed method is developed on the basis of the space-vector PWM in order to increase the linearly controllable voltage range. With the help of the proposed voltage synthesis method, the total harmonic distortion of the output stage can be greatly reduced in compared with that of conventional method with sinusoidal PWM or that of the single inverter operation case. The experimental results with reduced scale test show the feasibility of the proposed voltage synthesis method.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.99-106
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• 2003

This paper presents a novel multilevel PWM inverter employing series-connected transformers in order to improve the waveshape of output voltage and to reduce its harmonics. The proposed 11-level inverter consists of three full-bridge inverter modules and their corresponding transformers. Among their inverter modules, one is used as PWM operation and the others as level generation. From a suitable selection of turns ratio of transformer, continuous output voltage levels were generated appearing an integral ratio to input DC source. Because of their series connection of transformers, output filter inductor is not necessary. The operational principles and analysis are explained, and it is compared with a conventional multilevel PWM inverter. The validity of the proposed system Is verified through the experimental results using a prototype.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.7
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• pp.551-556
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• 2003

The present study concerns an experiment on the heating characteristics of a system air-conditioner (A/C) using PWM method or inverter method at low temperature con-ditions. The compressors used are digital scroll type and BLDC inverter type. Under the low outside temperature condition, -5$^{\circ}C$, -1$0^{\circ}C$, -15$^{\circ}C$, heating capacities and COPs are mea-sured by the psychometric calorimeter using air enthalpy method. Also, outlet air temperatures at heating operation mode are measured at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$. Experimental results show that COPs of the system A/C using a PWM method are more effective than those of the inverter method at heating operation mode. Although the heater is on, COPs of PWM method are similar to those of BLDC inverter method. Moreover, the heating capacities of PWM method at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$ are larger about 10~20% and outlet air tempe-rature at -15$^{\circ}C$ is larger about 10%, compared to the inverter method.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.63-68
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• 2002

In a utility interactive photovoltaic generation system, a PWM inverter is used for the connection between the photovoltaic arrays and the utility. The do current becomes pulsated when the conventional inverter system operates in the continuous current mode and dc current pulsation causes the distortion of the ac current waveform. To reduce pulsation of dc input current, This paper presents a Buck-Boost PWM power inverter and its application for residential photovoltaic system. The PWM power inverter is realized by combining two sets of a high frequency Buck-Boost chopper and by making it operate in the discontinuous conduction mode. In this paper, we show the Buck-Boost PWM power inverter circuit, its equivalent circuit and basic differential equations and the power flow characteristics are clarified when the proposed Inverter is interconnected with the utility lines. In conclusion, the proposed inverter system provides a sinusoidal ac current for domestic loads and the utility line with unity power factor

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.261-266
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• 2015

This paper presents a newly proposed prototype of voltage-fed half-bridge partial resonant zero voltage switching PWM inverter operating at a constant frequency variable power regulation scheme, which is more suitable and acceptable for induction heated(IH) cooking appliances. This application-specific high frequency inverter circuit topology using a new generation specially-designed IGBTs can operate under a principle of a fixed frequency ZVS-PWM strategy. The operating principle of a new partial resonant inverter circuit is described on the basis of its computer-aided simulation analysis, its including steady-state operating characteristics.

• Journal of Power Electronics
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• v.11 no.1
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• pp.74-81
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• 2011

The cutoff frequency of the output LC filters of PWM inverters limits the control bandwidth of the converter system while it attenuates voltage ripples that are caused by inverter switching activities. For a selected cutoff frequency of an output LC filter, an infinite number of L-C combinations is possible. This paper analyses the characteristics of output LC filters for PWM inverters terms of the L-C combinations. Practical circuit conditions such as no-loads, full resistive-loads, and inductive-load conditions are considered in the analysis. This paper proposes a LC filter design method for PWM inverters considering both the voltage ynamics and he inverter stack size. An experimental PWM inverter system based on the proposed output LC lter design uideline is built and tested.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.311-314
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• 1995

PWM(Pulse-Width Modulation) is frequently used as control method for inverter. In control of active silencer studied presently, PWM control method can be applied. This paper presents its possibility. As operating source of loudspeaker, inverter is used instead of audio amplifier and PWM controller controls the inverter to make canceling sound. This paper presents that active silencer of inverter-type using the PWM control method makes the canceling sound to acoustic noise and cancels the acoustic noise.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.58-62
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• 2017

This paper presents a novel prototype of the resonant AC link snubber circuit for the three-phase sinwave soft-switching PWM inverter. In principle, its operating principle is described, and the performance evaluations of the specific instantaneous space voltage modulated three-phase sinewave soft switching PWM inverter incorporating a resonant AC link snubber is illustrated, and evaluated, introducing the specific space voltage vector modulation implementation. It is conferred that the validity of three-phase soft-switching inverter treated here in setup experiment.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.688-691
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• 1999

Recently, it is increased to adopt inverter system to household electrical appliances, especially in ai conditioner and refrigerator. Inverter system is adopted for improving the efficiency. But Inverter system makes acoustic noise caused by switching frequency. In household electrical appliace, it is important to reduce acoustic noise. And in some cases it is possible to magnify the acoustic noise caused by switching, by system which may have different transfer characteristic. In this paper, random PWM method was adopted in inverter refrigerator using 8 bit microprocesso. We found useful PWM frequency and adoptation method.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.527-530
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• 1989

In order to reduce harmonic contents in the inverter output, various PWM ( pulse with modulation ) techniques have been utilized. This paper suggests a single phase inverter with 4-level output and its PWM control scheme. The proposed 4-level output inverter shows better performence than the 3-level output one in respects of the current error and the switching frequency.