Three programmed rapid-start control schemes for the electronic ballasts with a half-bridge series-resonant inverter are proposed to improve the starting performance of the rapid-start fluorescent lamps. Included are: (1) programmed rapid-start control scheme with an ac switch, (2) programmed rapid-start control scheme with inductively coupled filament-heating circuit, and (3) programmed frequency control scheme with a series-resonant energy-tank.
The first control scheme is simply to add a solid-state ac switch onto the series-resonant electronic ballast to provide programmed rapid-start for the rapid-start fluorescent lamp. The ac switch is turned on to have a zero voltage across the lamp to eliminate the glow current during the preheating interval. By adjusting the operation frequency and the duty-ratio, the electronic ballast produces first an adequate resonant current for preheating the cathode filaments, then a sufficiently high lamp voltage for ignition, and finally a stable lamp arc of the required lamp power.
The second control scheme is accomplished by adding two auxiliary windings on the inductor of the power-factor-correction (PFC) circuit for the filament-heating circuits. During the preheating period, the PFC circuit is activated to provide the filament heating while the inverter remains idle to keep the lamp voltage at zero and hence to eliminate the glow current. After the filaments have been heated to the appropriate temperature, the inverter is initiated to ignite the lamp and then operate it at the required power.
The third control scheme is realized by programming the operation frequency of the electronic ballast with an additional series-resonant energy-tank on the load resonant network. During the preheating interval, the electronic ballast is programmed to operate at the resonance frequency of the series-resonant energy-tank to reduce the lamp voltage and hence to eliminate the glow discharge. With carefully designed circuit parameters, the electronic ballast is able to provide an adequate current for preheating. After the emission temperature has been reached, the operation frequency is adjusted to generate a high lamp voltage for ignition, and then is located at the steady-state frequency driving the lamp with the desired power and filament current.
In this dissertation, the mode operations of the proposed ballast circuits are analyzed in accordance with the conducting conditions of the power switches. The equivalent resistance model of fluorescent lamp is implemented to calculate the performances of the ballast-lamp circuit at steady-state. The design equations are derived and the computer analyses are performed with the fundamental approximation on the equivalent circuit models of fluorescent lamps. In addition, in order to accurately predict the operating characteristic of the preheating circuit, a mathematical model is developed to interpret the variations of the filament resistance during preheating. Finally, the laboratory electronic ballasts with the proposed control schemes are built and tested. Satisfactory performances are obtained from the experimental results.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0705104-200040 |
| Date | 05 July 2004 |
| Creators | Chen, Wei-Ming |
| Contributors | Jiann-Fun Chen, Chin-Sien Moo, Li-Ling Lee, Yong-Nong Chang, Tsorng-Juu Liang, Jia-You Lee, Faa-Jeng Lin, Chih-Chiang Hua |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0705104-200040 |
| Rights | unrestricted, Copyright information available at source archive |
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