• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.516-522
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• 2009

The dimmable magnetic ballast which applies the variable inductor needs a switching process for the dimming process, and it consists of mechanical relays because of costs and reliabilities. However, it is hard to operate with correct timing in mechanical relay, so relays reduce their own life time in inductive applications. Moreover this creates a destructive problem at the switching process. The life time reduction of relays means the life time reduction of the ballast. Thus, in this paper, we described the problem at the witching process in the dimmable magnetic ballast with a variable inductor, which consists of relays and the soft AC switching method in order to solve the problems. As result, we achieved the improvement of the life time and reliability of the ballast.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.166-171
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• 2008

This paper presents high efficiency control system of automotive 35W electronic ballast for high intensity discharge(HID) lamp using switching flyback converter with variable frequency. Considering performance, size and efficiency of ballast, the flyback converter is designed with planar transformer in converter stage. HID lamp demands a highly efficient ballast and very complex control circuitry that can control complex transient state for applying to automotive. The proposed electronic ballast system is composed of a flyback converter using planar transformer, a full bridge inverter, and a step up igniter. In this system, switching frequency of flyback converter is controlled by varying input voltage of HID ballast and the price and the size of HID ballast using planar transformer can be reduced. The performance and efficiency of the posed system are verified through various the experiment results.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.589-593
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• 2001

This paper presents a high frequency modulation electronic ballast for the metal halide lamp. As the proposed ballast operates in high frequency ranges (20kHz - 100kHz) and it can start up the lamp using the LC resonant circuit without external igniter, the proposed ballast is very compact. The proposed ballast is controlled with the modulated frequency in the range of 20kHz to 100kHz, and it has variable modulating frequencies between 200Hz and 2kHz in order to avoid the acoustic resonance phenomenon. In this paper, a new realtime acoustic resonance detection method is described and the experimental results with the proto-type ballast of 150W metal halide lamp with the dimming function are discussed.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1029-1037
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• 2008

As for track maintenance, Seoul Metro executes track bed improvement project from obsolete ballast track bed to concrete track bed in order to achieve maintenance free and to extend its LCC(Life Cycle Costing). When it comes to obsolete ballast track bed withdrawal task, now it is done solely relying on man power and ballast inhalation vehicle. In this paper, I suggested ballast cleaning system with lighter equipment to change manpower withdrawal tasks to mechanized ones. It is expected to improve work efficiency and economic benefits by applying track excavator having variable wheels and container etc, which is able to keep on the site.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.85-88
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• 2000

This paper was development a discharge lamp ballast in order to wave improvement of high power factor and high efficiency. The discharge lamp ballast consists of a power factor correction circuit and a correction circuit on switching frequency of inverter. Instead of passive power factor circuit, active power factor circuit is adopted. Because it has the advantage of size, weight, total harmonic distortion, out DC voltage regulation, and power factor. The power factor circuit with MG34262 is controlled by variable frequency discontinuous mode. Results experiments, discharge lamp ballast is showed to have excellent for the proposed electronic ballast's operation and characteristics.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.1
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• pp.70-79
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• 2003

In this paper, T5 28-watt fluorescent lamp ballast using a piezoelectric transformer is fabricated and its characteristic is investigated. Developed electronic ballast is composed of basic circuits and blocks, such as rectifier part, active power factor corrector part, frequency oscillation part using microcontroller and feedback control, piezoelectric transformer and resonant half bridge inverters. The fabricated ballast uses to variable frequency methode in external so exciting that the frequency of piezoelectric transformer could be generated by voltage control oscillator using microcontroller(AT90S4433). The current of fluorescent lamp is detected by feedback control circuit. The signal of inverter output is received using Piezoelectric transformer, and then its output transmitted to fluorescent lamp. Traditional electromagnetic ballasts operated at 50-60Hz have been suffered from noticeable flicker, high loss, large crest factor and heavy weight. A new electronic ballast is operated at high frequency about 75kHz, and then Input power factor, distortion of total harmonic and lamp current crest factor are measured about 0.9!35, 12H and 1.5, respectively Accordingly, the traditional ballast is by fabricated electronic ballast using piezoelectric transformer and voltage control oscillator because of its lighter weight, high efficiency, economic merit and saving energy.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.487-489
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• 2004

As the electrodes are not needed, the electrodeless lamps using the induction discharge have a long lifetime and are robust against the variable output condition of a ballast. This paper proposed a dimmable resonant inverter for the electrodeless lamps. The proposed resonant inverter formed a half bridge inverter adopted FWM to control the average output power of the inverter and the illumination of a lamp. In this paper, the proposed dimming algorithm was described and the prototype experimental setup for 100W electrodeless lamps was carried out to verify the validity of the proposed dimming method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.131-133
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• 2007

In a design of DC ballast for fluorescent lamp, pre-stage of DC-DC converter is required to keep the constant output lumen performance regardless of variable DC input voltage. In this paper, flyback topology is used for optimum performance of 32W lamp, and various important design points for successful operation over the whole operating range are described.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.690-699
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• 2011

A numerical model analysis was performed to analyze the stability of the mooring lines of an automatic submersible fish cage system in waves and currents. The fish cage system consisted of a 12-angled rigid frame, net cage, cover net, 12 upper floats, 12 tanks(for fixed and variable ballast), mooring lines, anchors, and a control station. Simulations were performed with the cage at the surface of the water and at a depth of 20 m. A Morison equation type model was used for simulations of the system in two configurations. The force parameters described both regular and random waves, with and without currents, and their values were input to the model. Mooring tension calculations were conducted on the mooring lines, grid lines and lower bridle lines of the cage. The stability of the mooring lines was checked under both static and dynamic conditions.

• Journal of Drive and Control
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• v.14 no.3
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• pp.18-24
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• 2017

The purpose of this paper is to develop a new submersible fish cage operated by a pneumatic system for offshore aquaculture. Although some researchers have investigated modeling and control of fish cages, such cages consist of variable ballast tanks that with closed cylinders and thus present a maintenance issue. In solving the issue the new submersible fish cage investigated consists of bottom-opening cylinders. Accordingly, we designed a mathematical model of the concept and applied Sliding Mode Control for nonlinear angle control. Some experiments conducted under assumed conditions indicate that the angle of the system converges to zero under all conditions and the control has the stability to balance the fish cage.