HID Lamps Fed With Square Waveforms: Dimming and Frequency Effects on Stability, Current Crest Factor, and Power Factor

In this paper, the dimming and frequency effects on stability, current crest factor (CCF), and power factor (PF) of high-intensity discharge lamps fed with square waveforms are experimentally evaluated. For this evaluation, the lamp was stabilized using resistances. The resistances were varied in function of the impedance of the lamp. The effects of dimming and frequency variation were observed for two types of lamps of different nominal powers. The results indicate the ranges in which the lamp is stable and the frontier values in which the lamp becomes unstable. The CCF and PF remain close to unity, and no acoustic resonances were observed during the applied tests.