• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.5
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• pp.431-439
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• 2006

This paper proposes a new commutation circuit for a PWM Cuk AC-AC converter. The proposed commutation circuit utilizes a modified Undeland snubber as a commutation aid. The snubber circuit has some good features such as reduction of voltage/current stress of the main switches and improved efficiency. The experiment results show the adaptability and feasibility of the proposed commutation circuit.

• Journal of Power Electronics
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• v.9 no.2
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• pp.232-242
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• 2009

In this paper, a matrix converter with improved low frequency output performance is proposed by achieving a one-step commutation owing to a general commutation circuit applicable to n-phase to m-phase matrix converters. The commutation circuit consists of simple resister and capacitor components, leading to a very stable, reliable and robust operation. Also, it requires no extra sensing information to achieve commutation, allowing for a one-step commutation like a conventional dead time commutation. With the dead time commutation strategy applied, the distortion caused by commutation delay is analyzed and compensated, therefore leading to better output linear behavior. In this paper, detailed commutation procedures of the R-C commutation circuit are analyzed. A selection of specific semiconductor switches and commutation circuit components is also provided. Finally, the effectiveness of the proposed commutation method is verified through a two-phase to single-phase matrix converter and the feasibility of the compensation approach is shown by an open loop space vector modulated three-phase matrix converter with a passive load.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.6
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• pp.927-935
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• 1994

Detailed analysis of the commutation circuit of the proposed wide-frequency current source inverter is given. In this inverter a spike-limit circuit and a precommutation circuit are used. The spike-limit circuit is intended to limit spike voltage which is arising during commutation time in a current source inverter, and the precommutation circuit to reuse the energy which flows from main inverter to spike-limit circuit during commutation time to aid commutation. Thus voltage stress of main thyristor is minimized. Since this inverter can be made up of thyristors for phase control, it has some advantage in high voltage and high power application.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1158-1160
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• 1992

A new dc/ac soft switched PWM convert having a dc-link commutation circuit is proposed. The commutation circuit implemented by utilizing a series resonant circuit while preparing for zero voltage switching of primary inverter. The converter provides both variable pulse width and position which is fundamentally different than converters. In this paper, the operating principles, design and control considerations analysis of a such a soft switched converter is analyzed.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.117-120
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• 1988

A new current source inverter (CSl) with dc-side commutation and load-side energy recovery circuit is proposed with analysis and explanation of the circuit operation. Proposed inverter overcomes the most drawbacks of the conventional CSI's - high device voltage stress, low operating frequency range, large commutation capacitance, etc. - by employing simultaneous recovery and commutation concept. The new CSI employs only one commutation capacitor and it can be built with considerably low cost. The commutation energies are temporarily stored into a large dc capacitor and recovered to the load side, thus the device voltage stress is low and the efficiency is high in the proposed inverter. Computer simulation results are given at the steady state, and a guideline determining the commutation circuit is given.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.8
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• pp.610-616
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• 1989

The line commutated inverter with GTO forced commutation is described in this paper. The presented circuit has one bypass GTO inserted in DC power side line commutated thyristor inverter. The extended commutation region with additional one GTO-commutation is clearly shown. Also, a new PWM pattern is presented to decrease the effects of harmonics for commutation. A criterion for designing the AC filter parameters to decrease harmonics of AC part is given. The simulation and experimental results clearly show that the proposed circuit can be adapted in the application of regeneration.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.6
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• pp.489-497
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• 2022

This work investigates the commutation characteristics of the current flowing through an electrical-contact-type switch to the semiconductor switch branch during the breaking operation of hybrid DC switchgear. A simple, reliable, low-cost natural commutation method is proposed, and the current commutation characteristics are analyzed in accordance with the conduction voltage drop of the semiconductor switch branch through experiments. A prototype 400 V/10 A class natural commutation type hybrid DC switchgear is set up. Its performance is verified, and its characteristics are analyzed.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.143-145
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• 2006

This paper proposes a snubber circuit for a PWM AC-AC Cuk converter. The proposed snubber applies a modified Undeland snubber as a commutation aid. The snubber circuit has some good features such as reduction of voltage/current stress of the main switches, improved efficiency. The experiment results show the adaptability and feasibility of the proposed snubber circuit.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.6
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• pp.588-599
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• 1992

This paper describes the variable speed drive of an induction motor by the line commutated inverter, which is operated in the forced commutation mode from start-up to operating point of load commutation. A novel forced-commutation circuit is proposed in this paper. The selection range of leading condenser to decide load commutation starting point is simulated by the sampling data of a general purpose IM and a high speed IM. The experiment to drive IM by a line commutated inverter with the proposed forced commutated circuits is performed. There was no problem in driving IM from standstill to starting point of load commutation by a line commutated inverter with forced commutation.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.731-735
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• 1993

When induction motor is driven with a load commutated inverter, the output part of the inverter must be capacitive. But, in order to be a good load commutation at the low speed range, very large capacitor or force commutated circuit must be used regarding the capacity of motor. This paper proposed the force commutated circuit for driving the motor in case of the installation of capacitor which can be capable of load commutation at the rating speed. The force commutated circuit is operated by the LC resonant circuit, auxiliary source and SCR, and also composed of the commutation circuit which control the interval of the inverse voltage across the inverter.