Abstract
This paper presents an experimental study on the behavior of a fluorescent lamp. The modelings of the fluorescent lamp before and after firing are proposed. The fluorescent lamp characterizes its behavior as an impedance especially in the high frequency. It can be modeled as a series combination of resistance and capacitance after firing. Both two elements are function of the lamp current, the operating frequency, and the lamp voltage. A half-bridge series-resonant parallel-loaded inverter (HB-SRI) is proposed for measuring the characteristic of the fluorescent lamp. Interestingly, the resonant frequency of the HB-SRI is dependent on the mentioned three variables. A design example of the HB-SRI inverter is presented for dimming a 40-Watt fluorescent lamp. The dimmer strategy to dim the fluorescent lamp is realized by varying the operation frequency or the power factor correction (PFC) output voltage. Three dimming sections are examined, and the proposed ballast provides a power factor up 0.997, lower temperature rise of below 27°C, near 8 watts of power saving, and 10% increase of luminous efficacy.
