Electronic System Group Huang-Jen Chiu, Associate Professor

Electronic System GroupHuang-Jen Chiu, Associate ProfessorPh.D., National Taiwan University of Science and TechnologyField of study: Power Electronic, EMC, Circuit DesignKey words: Power Conversion, Switching Power Supply, PFCURL: http://homepage.ntust.edu.tw/HJCHIU/Email: hjchiu@mail.ntust.edu.twPhone: 886-2-273764191. The Subject and Aims of ResearchResearch interests include switching power supply design, power filteringtechniques, electronic ballast, power factor correction, EMC issues, battery chargingtechniques and DSP control applications.2. Related Recent Research Topics• Bidirectional DC/DC Converter for Fuel Cell Electric Vehicle Driving SystemIn recent years, growing concerns about environmental issues have demandedmore energy efficient nonpolluting vehicles. The rapid advances in fuel celltechnology and power electronics have enabled the significant developments in fuelcell powered electric vehicle. The fuel cells have numerous advantages such as highdensity current output ability, clean electricity generation and high efficiencyoperation. However, the fuel cell characteristics are different from that of thetraditional chemical-powered battery. We proposed a high efficiency bidirectionalisolated DC/DC converter for fuel cell electric vehicle driving systems. The newconverter has the advantages of high efficiency, simple circuit and low cost.• Single-Stage High-Frequency HID Lamp Electronic BallastBecause of the excellent luminous efficacy, color rendition and lifetimecharacteristics, High Intensity Discharge (HID) lamps have been used in variouscommercial applications such as automotive headlights, street lighting, and LCDprojectors, etc. We proposed a single-stage high-frequency electronic ballast fordriving HID lamps. High power factor and high efficiency can be simultaneouslyachieved. Compare with the conventional two-stage electronic ballast, the single-stageballast presents a simple configuration and high power density due to the componentcount reduction. A new frequency-modulation circuit is used to eliminate the acousticresonance problem in HID lamps under high frequency operation. The new methodhas the merits of simple circuit and low cost, thus it is suitable for commercialapplications.• Rapid Charger for Lead-Acid Batteries with Energy RecoveryThe lead-acid battery is widely used in various applications such as automotivepower system, uninterruptible power system (UPS), and telecom power supply, etc.However, poor battery energy density characteristics, charging time and lifetimeencumber commercial applications. The main aim of rapid charging is to shorten thecharge time and prolong the battery lifetime. We proposed a novel single-stage rapidcharger with energy recovery. While providing the high charging efficiency andprolonging battery lifetime, the proposed charger exhibits high power factor,simplicity and lower cost than the conventional consumption-load charger.• High Performance Driver Circuit for High-Luminance LEDRapid advances in material and manufacturing technologies have enabledsignificant developments in high-luminance LEDs for lighting applications. LEDlamps have numerous advantages, such as up to 100,000 hours of operative life, a

wide range of operation temperature, and the simplicity of a driver circuit: work withlow and safe voltages and no ignition circuit required like fluorescent lamps. Weimplemented an improved single-stage Flyback PFC converter for drivinghigh-luminance LED lamps. The lamp current can be largely reduced with theproposed constant current control scheme. High power factor and high efficiency canbe achieved under a wide range of the input voltage and lamp voltage variations.3. Selected Publications and ProjectsPublications:• H. J. Chiu and L. W. Lin, “Current Imbalance Elimination for a Three-PhaseThree-Switch PFC Converter,” IEEE Trans. on Power Electronics, vol. 23, no. 2,pp. 1020-1022, Mar. 2008. (SCI)• H. J. Chiu, H. M. Huang, H. T. Yang, and S. J. Cheng, “An ImprovedSingle-Stage Flyback PFC Converter for High-Luminance Lighting LEDLamps,” International Journal of Circuit Theory and Applications, vol.36, pp.205-210, Mar. 2008. (SCI)• H. J. Chiu, T. H. Song, S. J. Cheng, C. H. Li, and Y. K. Lo, “A Single-StageHigh-Frequency HID Lamp Electronic Ballast”, IEEE Trans. on IndustrialElectronics, vol. 55, no. 2, pp. 674-683, Feb. 2008. (SCI)• H. J. Chiu, T. F. Pan, C. J. Yao, and Y. K. Lo “Automatic EMI Measurement andFilter Design System for Telecom Power Supplies”, IEEE Trans. onInstrumentation and Measurement, vol. 56, no. 6, pp. 2254-2261, Dec. 2007.(SCI)• H. J. Chiu and S. J. Cheng “LED Backlight Driving System for Large-scale ofLCD Panels”, IEEE Trans. on Industrial Electronics, vol. 54, no. 5, pp.2751-2760, Oct. 2007. (SCI)• H. J. Chiu and S. J. Cheng, “Single-Stage Voltage Source Charge PumpElectronic Ballast with Switched-Capacitor Dimmer for Multiple FluorescentLamps,” IEEE Trans. on Industrial Electronics, vol. 54, no. 5, pp. 2915-2918,Oct. 2007. (SCI)• C. H. Lin, Y. Lu, H. J. Chiu, and C. L. Ou, “Eliminating the Temperature Effectof Piezoelectric Transformer in Backlight Electronic Ballast by Applying theDigital Phase-Locked Loop Technique”, IEEE Trans. on Industrial Electronics,vol. 54, no. 2, pp. 1024-1031, Apr. 2007. (SCI)• Y. K. Lo, J. M. Wang, H. J. Chiu, and C. H. Chang, “Dual Mode ControlMultiphase DC/DC Converter,” IET Proc.-Electric Power Applications, vol. 1,no. 2, pp. 229-238, March 2007. (SCI)Projects:• High-Frequency Electronic Ballast of Xenon Lamps for Automotive Headlight,Architectural Lighting and LCD Projection Systems (1/3) , NSC96-2628-E-011-115-MY3。