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Please use this identifier to cite or link to this item: http://hdl.handle.net/2031/5548

Title: An investigation into new control methods for electronic and electromagnetic ballasts
Other Titles: Xin dian zi ji dian ci zhen liu qi kong zhi fang fa zhi yan jiu
新電子及電磁鎭流器控制方法之研究
Authors: Lee, Leung Ming (李亮明)
Department: Department of Electronic Engineering
Degree: Doctor of Philosophy
Issue Date: 2008
Publisher: City University of Hong Kong
Subjects: Ballasts (Electricity)
Electronic controllers.
Power electronics.
Notes: CityU Call Number: TK7881.2 .L53 2008
271 leaves : ill. 30 cm.
Thesis (Ph.D.)--City University of Hong Kong, 2008.
Includes bibliographical references (leaves 185-191)
Type: thesis
Abstract: Large infrastructures such as underground railway systems and airports use a wide range of lighting devices with different power ratings for indoor lighting, predominantly fluorescent lamps. Fluorescent lamps use ballasts to provide ignition voltage and to regulate the lamp current. Ballast ensures the lamp continues to operate despite cycling through zero voltage of the mains supply twice. With all these functions, ballasts are essential for the operation of standard fluorescent lamps. For the existing T8 and T12 tubular fluorescent lamps, they are generally classified into nine major lamp types. However, with recent availability of new energy efficient T5 tubular fluorescent lamps, the number of major lamps types has doubled to 18. Electronic ballasts are generally designed for specific lamp types and lamp rated powers, any mismatch of ballast and lamp power ratings will often lead to damage of lamp or ballast. To date, there is no lamp power detection technique or electronic ballast design that can detect the lamp power and operate different lamps at the appropriate power levels, although some ballast products can be used for narrow range of tubular fluorescent lamps with similar power ratings. The sudden increase in the lamp types creates more inconveniences to both ballast manufacturers and consumers. Universal Electronic Ballast: In the first part of this thesis, the characteristics, including lamp voltage, lamp current and values of hot filament resistance of lamp of all existing tubular fluorescent lamps are reviewed and analysed. In the research, it was found that the value of the hot filament resistance of lamps can be used to identify the main groups of lamps. If the lamp voltage is detected, most types of lamps can be differentiated. For some types of lamps, lamp voltages are so close that the lamp current must be used for lamp identification. Such analysis can be used to develop a systematic approach to differentiate the major tubular fluorescent lamps according to their hot filament resistance of lamp, lamp voltage and lamp current. Large infrastructures such as underground railway systems and airports use a wide range of lighting devices with different power ratings for indoor lighting, predominantly fluorescent lamps. Fluorescent lamps use ballasts to provide ignition voltage and to regulate the lamp current. Ballast ensures the lamp continues to operate despite cycling through zero voltage of the mains supply twice. With all these functions, ballasts are essential for the operation of standard fluorescent lamps. For the existing T8 and T12 tubular fluorescent lamps, they are generally classified into nine major lamp types. However, with recent availability of new energy efficient T5 tubular fluorescent lamps, the number of major lamps types has doubled to 18. Electronic ballasts are generally designed for specific lamp types and lamp rated powers, any mismatch of ballast and lamp power ratings will often lead to damage of lamp or ballast. To date, there is no lamp power detection technique or electronic ballast design that can detect the lamp power and operate different lamps at the appropriate power levels, although some ballast products can be used for narrow range of tubular fluorescent lamps with similar power ratings. The sudden increase in the lamp types creates more inconveniences to both ballast manufacturers and consumers. Universal Electronic Ballast: In the first part of this thesis, the characteristics, including lamp voltage, lamp current and values of hot filament resistance of lamp of all existing tubular fluorescent lamps are reviewed and analysed. In the research, it was found that the value of the hot filament resistance of lamps can be used to identify the main groups of lamps. If the lamp voltage is detected, most types of lamps can be differentiated. For some types of lamps, lamp voltages are so close that the lamp current must be used for lamp identification. Such analysis can be used to develop a systematic approach to differentiate the major tubular fluorescent lamps according to their hot filament resistance of lamp, lamp voltage and lamp current. The analysis of the lamp voltage and lamp current indicates that these two lamp characteristics are nonlinear in real time. Therefore, one cannot use traditional linear control methodologies, such as PI or PID controller to differentiate and operate them optimally. Alternatively, fuzzy logic control is proposed for the lamp detection based on the three critical reference data, the hot filament resistance of lamp, lamp voltage and lamp current. In the Fuzzy logic design, the fuzzy rules and their arrays are established first and comply to the manufacturers’ requirements. According to the manufacturers’ technical data, the input membership functions for three reference input data can be determined and so are their consequent membership functions of the lamps. The defuzzification method adopted in the fuzzy logic design is an algorithm called “Center-average”, which is confirmed as an efficient and effective algorithm for lamps detections. Through the careful design of the relevant member functions, the new universal electronic ballast can provide the optimum output power for the tubular fluorescent lamps. In order to have a computationally efficient fuzzy logic controller in universal electronic ballast, a programming technique “Table Look-up” is adopted to implement the fuzzy logic control and to reduce the program running time. For the simulation-based evaluations of the voltage-mode filament-heating series resonant circuit in the universal electronic ballast, a new mathematical model has been developed to dramatically reduce the system development time for the hardware and software design, especially in the lamp data tables design in the fuzzy logic controller. From the various evaluated results, it is found that the combined approach of the new lamp detection technique and the fuzzy logic implementation provides accurate, reliable and highly stable performance in the lamp detection process and optimal lamp power operation. Consequently, problems arising from the mismatch of ballast and lamp power ratings can be eliminated. In this thesis, this new concept has been proven applicable to a wide range of tubular fluorescent lamps and can be easily incorporated into existing electronic ballast control. During our research, the high running voltage of some high lamp voltage T5 lamps, such as T5HE-35W, caused some adverse effects that cannot be minimized by the high non-reclosed voltage glow-switch starter. Defect of non-stop flickering still takes place in the said T5 lamps. In order to eliminate the extra voltage to the starter, the second approach for high-power lamps (>25W) is to use a semiconductor device, called “Varistor”, in the electromagnetic ballast circuit. This device can absorb a great deal of energy spikes and can limit the voltage. With this special characteristic, the high running lamp voltage across the starter can be further reduced. In addition, for the high ignition voltage, the step-up transformer is proposed to be used to increase the mains voltage to such voltage level that the high lamp voltage T5 lamps can be ignited. By adding these two said devices and a high non-reclosed voltage glow-switch starter, the electromagnetic ballasts can be used with T5 lamps. A new mathematical model has also been developed for the electromagnetic ballast circuit design so that one can determine the inductance value of the choke in the electromagnetic ballast. As a result, the system development time can be reduced dramatically. By the experimental results, these systematic approaches have been confirmed.
Online Catalog Link: http://lib.cityu.edu.hk/record=b2340806
Appears in Collections:EE - Doctor of Philosophy

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