Applying Asymmetrical Half-Bridge LCC Resonant Inverter to EEFL Lighting Ballast
2010
Hochschulschrift
Zugriff:
99
In this thesis, an asymmetric half-bridge LCC resonant inverter is presented, which is the kernel of the proposed lighting ballast that is used to drive the an external electronic fluorescent lamp (EEFL). Such a lighting ballast contains three power stages. The first power stage is constructed by a boost converter with power factor correction (PFC), and such a the converter is operated in the transient mode (TM) with the DC output voltage 390V. The second power stage is built up by a buck converter which uses a pulse-width-modulation (PWM) control integrated circuit (IC) to control the duty cycle such that the corresponding output voltage can be changed and hence dimming of the EEFL can be achieved. The third power stage is established by an asymmetric half-bridge LCC resonant inverter. Via LCC resonant, the power switches of this inverter are operated in zero voltage switching (ZVS) to reduce the switching loss, and at the same time, the inherent high voltage conversion characteristics make the voltage conversion gain be high than one such that the turn ratio of transformer can be reduced. In this paper, only the third stage is simulated based on IsSpice. Via the primary and secondary leakage inductances of the transformer along with one external series capacitance, the LCC resonant are simulated under open-loop control. The simulated results must guarantee to the power switches with ZVS turn-on and the high voltage conversion gain. After this, one asymmetric half-bridge LCC resonant inverter is carried out based on the designed transformer. Accordingly, the measured and simulated results are verified alternately. Furthermore, this inverter is reduced to an equivalent non-isolated circuit, and hence the corresponding transfer function can be obtained. Based on such a transfer function, the effect of resonant parameters and switching frequency on the voltage gain can be known. Finally, the inverter, together with the other two power stages, is used to drive and dim EEFL.
Titel: |
Applying Asymmetrical Half-Bridge LCC Resonant Inverter to EEFL Lighting Ballast
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Autor/in / Beteiligte Person: | Chen, Kuo-Yang ; 陳國揚 |
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Veröffentlichung: | 2010 |
Medientyp: | Hochschulschrift |
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