Modified Synchronous-Buck Converter for a Dimmable HID Electronic Ballast
ABSTRACT In this paper, a simple and effective way of increasing the efficiency of a three-stage low-frequency dimmable high-intensity-discharge (HID) electronic ballast is proposed. To increase the efficiency at all dimming levels, a modified synchronous-buck converter operating in a new critical conduction mode is presented. The proposed modified topology of the synchronous-buck converter operates in a soft-switching mode and therefore significantly increases the efficiency of the three-stage low-frequency HID electronic ballast at all dimming levels. Analytical and experimental results for a dimmable 400-W HID lamp are presented.
Conference Paper: A universal programmed start dimming ballast platform[Show abstract] [Hide abstract]
ABSTRACT: In this paper, a novel universal programmed start dimming ballast platform for fluorescent lamps is proposed. The proposed platform consists of an independent PWM type filament heating control circuit for filaments preheat and filament heating in dimming condition. Mathematical analysis of the proposed method is discussed in the paper. Experimental results of T8 32watt and T5 28watt lamps are presented to validate the proposed method.Industry Applications Society Annual Meeting (IAS), 2012 IEEE; 01/2012
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ABSTRACT: This paper presents the analysis, design, simulation and experimental results of a digital control strategy applied to an electronic ballast to supply a 70-W high-pressure-sodium lamp. The electronic ballast consists of a single-stage converter that integrates a buck converter to provide power factor correction and two flyback converters to supply the lamp, with low frequency square waveform, in order to avoid the acoustic resonance phenomenon occurrence. The proposed digital control strategy is composed of three control loops: voltage loop for lamp ignition and warm-up, an inner current loop for steady state, and a slow outer power loop to maintain the lamp power constant during its useful life. The lamp dynamic model is included to the ac model of the converter, so the effects of its right-half-plane zero are considered to design the digital control system. Fixed-point simulation is presented using Q base number format, where the exact variable values employed in the microcontroller code are used. Experimental results are included to demonstrate the performance of the proposed digital control strategy.IEEE Transactions on Industrial Electronics 01/2013; 60(2):608-618. · 6.50 Impact Factor
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ABSTRACT: High-intensity-discharge (HID) lamps are widely utilized in a variety of lighting circumstances that need high luminance. This paper proposes a single-stage electronic ballast for HID lamps; the ballast offers power factor correction and is acoustic resonance free. The presented HID lamp ballast integrates a discontinuous-conduction-mode (DCM)-operated bridgeless power factor correction (PFC) converter for shaping the input utility-line current with a high-frequency (36 kHz)/low-frequency (60 Hz) square-wave-driven half-bridge inverter for supplying low-frequency (60 Hz) square-wave sources to the HID lamp. The features of the proposed ballast are high power factor, low total harmonic distortion (THD) of the input current, cost effectiveness, and that it avoids acoustic resonance. The operational modes, key design guidelines, and a design example are included. A 70 W prototype HID lamp ballast circuit operating with 110 V-rms input utility-line voltage has been implemented and testified. The functionalities of the presented ballast are demonstrated by satisfactorily experimental results with a maximum efficiency of 90.8%, a maximum power factor of 0.998, and a minimum current THD of 11.13%.IEEE Transactions on Power Electronics 01/2014; 29(4):1966-1976. · 5.73 Impact Factor