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Cheng H.-L.,I - Shou University | Cheng C.-A.,I - Shou University | Chang Y.-N.,Formosa University | Tsai K.-M.,I - Shou University
IET Power Electronics | Year: 2013

This paper proposes a high-power-factor electronic ballast for metal-halide (MH) lamps. In the proposed circuit, two buck-boost converters and a buck converter are integrated with a full-bridge inverter by sharing the four active switches of the full-bridge inverter. Two active switches are switched at high frequencies, while the other two are switched at lower frequencies. The buck converter is used to step down the DC-link voltage of the full-bridge inverter and filter out the high-frequency components to drive lamps with a low-frequency square-wave (LFSW) current. The buck-boost converters are operated at discontinuous-conduction mode to perform the function of power-factor correction (PFC) to ensure almost unity power factor at the input line. By tactful arrangement of diodes, the DC-link capacitors are discharged in parallel; this helps to operate the high-frequency active switches at a high duty ratio, achieving a small peak value of the PFC-converter current and correspondingly smaller conduction losses. Detailed operation modes and the design equations are provided. A prototype electronic ballast for a 70 W MH lamp is built and tested. Experimental measurements have proven that the proposed electronic ballast has the advantages of high-power factor and being free of acoustic resonance. By integrating the active switches of the converters and the inverter, the proposed electronic ballast is advantageous in terms of cost-effectiveness and high energy-conversion efficiency. © The Institution of Engineering and Technology 2013.


Cheng H.-L.,I - Shou University | Hsieh Y.-C.,Dong - A University | Chang Y.-N.,Formosa University | Tsai K.-M.,I - Shou University
2010 IEEE International Conference on Sustainable Energy Technologies, ICSET 2010 | Year: 2010

This paper proposes a high power-factor electronic ballast for metal halide lamps. In the proposed circuit, two buck-boost converters and a buck converter are integrated with a full-bridge inverter of which the four active switches are shared. Two active switches are switched at high frequency, while the others are switched at low frequency. The buck converter is used to step down the dc-link voltage of the fullbridge inverter and filter out the high-frequency voltage components to drive lamps with a low-frequency square-wave (LFSW) voltage. The buck-boost converters are operated at discontinuous-conduction mode (DCM) to perform the function of power-factor-correction (PFC) to ensure nearly a unity power factor at the input line. By tactful arrangement of diodes, the dc-link capacitors are charged in series and discharged in parallel. It helps to operate the high-frequency active switches at a high duty ratio to have a small peak value of the inductor current of the PFC converters, and then smaller conduction losses. Detail operation modes and the design equations are provided. A prototype electronic ballast for a 70 W metal halide lamp is built and tested. Experimental measurements have proven that the proposed ballast has the advantages of high power factor, and free of acoustic resonance. By integrating the active switches of the converters and the inverter, the product cost of the proposed electronic ballast can be effectively reduced. ©2010 IEEE.


Hwang S.-J.,Formosa University | Tsai C.-T.,National formosa University | Liu W.-L.,National formosa University
Advanced Materials Research | Year: 2012

Alumina nanostrips were prepared on aluminum plate surface by anodizing in oxalic acid and etching in phosphonic acid sequentially. The alumina nanostrips were characterzed by scanning and transmission electron microscopes for the morphologies structuzes,and crystal structures, by an energy dispersive x-ray spectroscope for the chemical composition, and by a photoluminescence measurement system for the photoluminescence. The results show that the alumina nanostrips are amorphous, have a chemical composition of Al 2O 3-x, and can emit a blue light about 440nm in photoluminescence.


Chang Y.-T.,Kao Yuan University | Huang J.-F.,National Cheng Kung University | Yen C.-T.,Formosa University | Cheng H.-C.,Formosa University | Hsu K.-c.,National Cheng Kung University
Optical Fiber Technology | Year: 2010

This paper exploits the inherent cyclic and periodic free-spectral-range (FSR) properties of arrayed-waveguide grating (AWG) routers to construct a two-dimensional (2D) time-spreading and wavelength-group-hopping embedded M-sequence code for optical multiple-access networks. In the proposed codecs (encoder/decoder), a fine arrayed-waveguide grating (AWG) is used to generate an M-sequence code pattern, which is then spread in the wavelength domain by multiple coarse AWGs. The signals produced at the output ports of the coarse AWGs are then spread in the time domain using optical delay lines. The 2D code is evaluated in terms of its correlation, bit-error-rate (BER) and cardinality characteristics. It is shown that the TS/GH embedded M-sequence code yields a significant improvement in both the BER and cardinality performance of the optical multiple-access networks compared to that obtained using conventional prime-hop code (PHC), modified prime-hop code (MPHC), Barker and Walsh-based bipolar-bipolar sequence. © 2010 Elsevier Inc. All rights reserved.


Hsieh W.-H.,Formosa University | Chen T.-I.,Formosa University
Science China Technological Sciences | Year: 2010

A bionic jellyfish is a robot that can mimic the swimming of a real jellyfish. In practical application, the volume and the capacity of its carrying power are limited, hence its power consumption is a crucial factor for continuous swimming. The purpose of this paper is to propose an approach for the resonance analysis of bionic jellyfishes in order to investigate their energy efficiency in swimming. First, a suitable rigid-body bionic jellyfish was chosen from the previous study, and then its design approach was presented, Then, it was transformed into a compliant design, by the proposed method, in order to mimic the motion of a real jellyfish. Furthermore, its solid model was drawn, and the approach of modal analysis by using ANSYS software was addressed. After that, two terms, specific energy and energy ratio, were defined in order to evaluate its energy efficiency. Finally, a design example was given for illustration, and its motion simulations with and without resonance input were conducted by using ADAMS software. Additionally, their specific energies and energy ratios were found. The simulation results showed that the required input energy would be significantly reduced if a bionic jellyfish swims at its resonance frequency. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg.

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