• Journal of Power Electronics
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• v.10 no.5
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• pp.451-460
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• 2010

This paper presents a new kind of digital control metal halide lamp electronic ballast. A zero-voltage-switch quasi-square-wave (ZVS-QSW) dual Buck converter is adopted here. In this paper, a digital control method is proposed to achieve ZVS for the converter. This ZVS can be realized during the whole working condition. Single-cycle-peak-current control is proposed to solve the problem of excessive inductor current during a low-frequency reversal transient. Power loop control is also realized and its consistency for different lamps is good. An AVR special microcontroller for a HID ballast is used to raise the control performance, and the low-frequency square-wave control method is adopted to avoid acoustic resonance. A 70W prototype was built in the laboratory. Experimental results show that the electronic ballast works reliably. Furthermore, the efficiency of the ballast can be higher than 92%.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.43-49
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• 2000

In this paper, a new control method is presented to reduce acoustic resonance phenomena of metal halide lamps with electronic ballasts. A behavior of frequency controlled resonant inverter is analyzed and the transfer function is obtained. An integrator as a current controller for ballast is employed. By using both a disturbance of the lamp power and spread spectrum effects for reducing acoustic resonance, an amplitude modulation is done by using the current controller with 200[Hz] sinusoidal wave. Arc stabilities of MH 250[W] lamps are studied with changing the modulation index. Experiments with two MH 250[W] lamps, made by different manufacturers, showed the validity of the proposed method.

• Korean Journal of Optics and Photonics
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• v.25 no.6
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• pp.315-325
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• 2014

A combination of MHL and LED fish-luring light is used in this study. Its yield, characteristics, and irradiance distribution are evaluated and analyzed. To obtain an irradiance distribution similar to that of an MHL, we suggest the optimal arrangement of MHL and LED.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.737-740
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• 2001

This paper proposes a new ballast that is ignited by internal LC resonance of buck converter. In order to cancel the steady state current ripple, the proposed ballast utilizes the coupled inductor filter which minimizes the size and weight of the ballast. The operation mode of the proposed ballast is analyzed and the performance of the new ballast is verified by the experimental results from a HOW prototype ballast for metal halide discharge (MHD) lamp.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1981-1987
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• 2008

This paper proposed one of various acoustic resonance reduction technique for three kinds of ceramic lamps (CDM-150, HCI-150, CMH-150). To reduce the acoustic resonance in the HID lamps, the researched results showed that the frequency modulated signal with the triangle waveform is very effective in order to drive th LCC type half-bridge inverter for HID lamp. Experimental results proved that the acoustic resonance could be rejected, if the adequate switching frequency band is selected and the driving signal frequency is modulated with a triangle waveform.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.12
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• pp.25-32
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• 2010

Compared to general lighting method, the lighting system that uses optic fiber can provide only the visible light of good quality to subject by eliminating ultraviolet ray and infrared ray. Thanks to this merit, it is possible to prevent the hard phenomenon of subject caused by ultraviolet ray and infrared ray and to provide the agreeable light environment. This study developed indoors illumination system of high color rendering on the basis of plastic optic fiber with excellent optical property and processing to substitute halogen lamp which has been used for excellent color rendering in spite of low efficiency and short life. Producing pilot product of the designed illumination system and evaluating the property of electric and optical property, ultraviolet ray radiation quantity and temperature property, this study verified the excellence of suggested lighting system of plastic optic fiber.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.109-113
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• 2001

A high-efficiency electronic ballast for HID lamps is presented. The ballast consists of a PFC and a resonant inverter. To reduce losses of ballast,7C link voltage is determined by taking into account the peak voltage of lamp and a filter-inductor at Bridge diode is employed in order to remove harmonics from PFC. The flux density B$_{m}$ is kept 0.2[T] on all of inductors. A small inductor is connected in series with an electrolytic capacitor of PFC to be operated no high-frequency components. The acoustic resonance is eliminated using the spread spectrum technique. Electronic ballast for 250W metal-halide lamp is implemented and the experimental results show that 97% efficiency, no acoustic resonance and low conducted EMI level.l.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1538-1543
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• 2009

The electric ballast for ceramic metal halide lamp needs a protection circuit to prevent from over voltage and over current in the case that the lamp or the electric ballast are in faults. In this paper, cost-effective and high performance protection circuit is proposed for the electric ballast. The proposed protection circuit is adapted to the electric ballast with $LC_SC_P$ resonance type half bridge inverter. The experimental results demonstrate that the proposed circuit can protect effectively under open and short fault conditions.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.580-583
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• 2001

A high ignition voltage is required for the metal halide (MHD) lamp. In this paper, the ballast ignited by internal LC resonance of buck converter with minimum size is proposed. For minimizing the ignition current for device safety, the characteristic impedance is maximized. But this results In a large steady state ripple, which may cause the accoustic resonance. The steady state ripple cancellation network using the coupled inductor is proposed.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.400-407
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• 2013

This study was performed to analyze the effect of light quality of discharge lamp on growth and phytochemicals contents of lettuce (Lactuca sativa L. cv. Jeokchima) grown under metal halide (MH) lamp, high-pressure sodium (HPS) lamp, and xenon (XE) lamp in a plant factory. Cool-white fluorescent (FL) lamp was used as the control. Photoperiod, air temperature, relative humidity, $CO_2$ concentration, and photosynthetic photon flux (PPF) in a plant factory were 16/8 h (day/night), $22/18^{\circ}C$, 70%, 400 ${\mu}mol{\cdot}mol^{-1}$, and 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. MH lamp had the greatest fraction of blue light (400-500 nm) of 23.0%. However, HPS lamp had the lowest fraction of 4.7% for blue light and the greatest fraction of 38.0% for red light (600-700 nm). At 11 and 21 days after transplanting, leaf length, leaf width, leaf area, shoot fresh weight, and shoot dry weight of lettuce as affected by the light quality of the discharge lamp were significantly different. The leaf area of lettuce grown under HPS, MH, and XE lamp increased by 45.7%, 16.3%, and 9.5%, respectively, as compared to the control. These results were similar for shoot fresh weight. Growth characteristics of lettuce grown under HPS lamp increased since HPS lamp had more fraction of red light. However, growth of lettuce grown under MH and XE lamp decreased since they had more fraction of blue light. As compared to the control, the ascorbic acid in lettuce leaves grown under discharge lamp decreased. The greatest anthocyanins accumulation of 0.70 mg/100 g was found at MH treatment. Anthocyanins content in lettuce leaves grown under XL and HPS lamp were 79.3% and 8.6%, respectively, compared with the control. Growth and phytochemicals contents of lettuce were highly affected by the different spectral distribution of the discharge lamp. These results indicate that the combination of discharge lamp or LED lamp for enhancing the light quality of discharge lamps is required to increase the growth and phytochemicals accumulation of lettuce in controlled environment such as plant factory.