• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.558-560
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• 2004

Studies on the controlled switching method have been done to prevent the power system surges which cause the insulation deterioration and electro magnetic compatibility (EMC) problems during closing and opening of a circuit breaker. The controlled switching method controls the closing and tripping time in coincidence with the voltage or current to suppress switching surge. It is used to switch condenser bank, no load transformer, and shunt reactor. In this study, basic concept of the controlled switching is introduced, and also the test is performed to find parameters of the controlled switching in a 24kV vacuum circuit. And then, the control device hardware using TMS320C31 DSP has been designed and manufactured. It has been found that the application of IT technology to a circuit breaker is very effective to depress the switching surge.

• Journal of IKEEE
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• v.20 no.4
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• pp.373-377
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• 2016

This paper presents a low power boost converter using offset controlled Zero Current Sensor (ZCS) control for thermoelectric energy harvesting.[1] [5] Offset controlled ZCS uses adjustable pre-offset that is controled by 6bit code each connected gate of NMOS for switching. Offset controlled ZCS demonstrates an efficiency that is higher than using analog comparator ZCS and that is smaller area than using delay line ZCS. Experimentally, the offset controlled ZCS system consumes 10 times less power than analog comparator ZCS based system at similar performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5A
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• pp.452-456
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• 2010

SIR based beam switching in distributed controlled cellular systems is proposed to reduce intercell interference. Compared with Random beam switching that beam switching pattern is randomly selected and cannot avoid beam collision between neighboring cell, SIR based beam switching update its switching pattern based on SIR report from mobile. Neighboring cells independently update their switching patterns and the updated patterns converge to the patterns that minimize beam collision. We shows SIR base beam switching has 20% gain compared with random beam switching in two neighboring cell model.

• Proceedings of the KIEE Conference
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• summer
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• pp.563-565
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• 2004

It is expected to reduce stresses to components of high voltage circuit breaker and transferred switching surge from power system by applying controlled switching technique to high voltage system. This technique has at ready been applied in advanced countries. In this paper, basic principle of controlled switching technique is set up and a device to realize this technique is under developing. Controlled switching device will be improved by applying a method minimizing errors of operating time and by adopting compensation function relative to changes of ambient/operating condition.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.63-69
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• 1998

A new current controlled PWM technique with NPC structure is proposed in this paper. A current controlled PWM technique with neutral-point-clamped pulse-width modulation inverter composed of main switching devices which operates as switch for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential is described. The proposed current controller has a first and second current band. The switching pattern will be made by the first current band. According to the second current band, the output state of the switching pattern is changed into positive and negative state. This inverter output contains less harmonic content and lower switching frequency than that of conventional current controlled PWM technique at the same current limit. Two inverters are compared analytically and the performance is investigated by the computer simulation.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2148-2150
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• 1998

This paper proposes a constant frequency controlled zero voltage switching method that can reduce switching losses caused by emf on inductance in DC motor. The zero voltage switching method is used more than a zero current switching method because of reducing switching losses by capacitance of depletion region of MOSFET. To simplify the controller circuit, we propose constant frequency controlled zero voltage switching method in the paper. The control method is more stable than a variable frequency control method because it can optimize bandwidth of a closed-loop and reactances. Therefore, we construct a constant frequency controlled zero voltage switching converter and improve zero switching losses in high switching frequency. In the process, we can control low-losses in full range on variable voltage and load. We simulate the proposed converter with P-SPICE and compare results obtained through the experiment.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.237-239
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• 1994

The MOS-controlled thyristor(MCT) is a new power semi-conductor device that combines four layers thyristor structure presenting regenerative action and MOS-gate providing controlled turn-on and turn-off. The MCT has very fast switching speed owing to voltage controlled MOS-gate, and very low on-state voltage drop resulting from regenerative action of four layers thyristor structure. In addition, because of a higher dv/dt rating and di/dt rating, gate drive circuit and snubber circuit can be simpler comparing to other power switching devices. So recently much interest and endeavor is being applied to develop the performance and ratings of the MCT. This paper describes the switching characteristic of the MCT for its practical applications and presents a model for PSPICE circuit simulation. The model for PSPICE circuit simulation is compared to the experimental result using MCTV75P60F1 made by Harris co..

• Journal of Power Electronics
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• v.16 no.2
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• pp.498-511
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• 2016

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

• ETRI Journal
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• v.44 no.2
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• pp.274-285
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• 2022

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue-based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.3
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• pp.127-133
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• 2004

This paper presents a prototype of three-phase current source zero voltage soft-switching PWM controlled PFC rectifier with Single Active Auxiliary Resonant Commutated Snubber (ARCS) circuit topology. The proposed three-phase PFC rectifier with sinewave current shaping and unity power factor scheme can operate under a condition of Zero Voltage Soft Switching (ZVS) in the main three phase rectifier circuit and zero current soft switching (ZCS) in auxiliary snubber circuits. The operating principle and steady-state performances of the proposed three-phase current source soft-switching PWM controlled PFC rectifier controlled by the DSP control implementation are evaluated and discussed on the basis of the experimental results of this active rectifier setup.