Dynamics Analysis of Fluorescent Lamp and Electronic Ballast System

• Main Authors: Yu-Rong Chen, 陳昱榮
• Other Authors: Jong-Lick Lin
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/98959989873012526772

碩士 === 國立成功大學 === 工程科學系碩博士班 === 94 === <big><pre>　　The stability of the fluorescent lamp and ballast system is<br>investigated in this thesis. Fluorescent lamps are gas discharge<br>lamps. Based on its v-i characteristic curve derived by experimental<br>results, it reveals that the dynamics of the lamp is a negative<br>incremental impedance at high frequencies. The small-signal model of<br>the lamp is obtained by using the modified Francis first-order<br>differential equation described the behavior of the lamp.<br>Interestingly, the mathematical model is non-minimum phase with a<br>right-half plane zero. As a result, the lamp is regarded as a<br>current controlled device. A current source is thereby applied to<br>the lamp to stabilize the overall system. 　　The electronic ballast is composed of power transistors and<br>resonant circuit. Three resonant circuits under investigation are LC<br>series resonant circuit, LC parallel resonant circuit, and LCC<br>series and parallel resonant circuit. The phasor transformation is<br>applied to derive the small-signal model of the resonant circuits.<br>First, the circuit is transformed from the time domain into the<br>phasor domain. Then according to the equivalent phasor-domain<br>circuit, the transfer function is derived by the exact method and<br>approximate method presented in this thesis. Notably, the transfer<br>function of the equivalent phasor-domain circuit of the resonant<br>circuit can be simplified to be first-order lowpass filter on the<br>basis of the approximate method. 　　According to the small-signal model of the lamp and the first-<br>order lowpass filter of the resonant circuit, the stability of<br>system can be analyzed by Routh-Hurwitz criterion. Three systems for<br>stability investigation are resistive ballast for dc operation,<br>traditional inductive ballast for utility power of 60 Hz, and<br>electronic ballast for a square wave power source of 50 kHz<br>generated from the inverter. The theoretical analysis is validated<br>by experimental results. 　　For a practical engineer, the theoretical analysis and<br>experimental results in this thesis are helpful to gain insights of<br>the electronic ballast design.</pre></big>