The Study Of Acoustic Resonance Phenomenon For Low Frequency Square Wave Power Supply HID Lamps

High Intense Discharge lamps are often abbreviated to HID Lamps. MH lamps used acoustic resonance research are one kind of HID lamps in this paper. HID lamps is the third generation green energy-saving light sources with high-efficient, long life, good rendering index. Since HID lamps have negative impedance characteristics, it can not be directly added to the electricity grid. So, it needs ballast as the interface which restrains current between HID lamps and grid. HID lamps working in high frequency could induce the size and weight of electronic ballast, but they occur acoustic resonance phenomenon easily. When acoustic resonances appear, it cause perturbations in the HID lamp's discharge arc, yielding to light flickering, lamp electrical equivalent parameters variations and, in the worst case, arc extinction or lamp breaking. At present, acoustic resonance of HID lamps become an principal obstacle to developing HID lamps. Therefore, the research for acoustic resonance has great significance to China's lighting Project. In this paper, some research work has been made to acoustic resonance phenomenon as follows:1 The mechanism of HID lamp is studied. HID lamp works in arc discharge status in steady state. Acoustic resonance is due to the formation of the gas pressure wave created by standing wave. Plasma theory is introduced to explain the formative process of acoustic resonance. Meanwhile, the HID lamp models are studied at high or low frequency operation.2 According to electrical and physical characteristics when acoustic resonance occurs, several methods for detecting acoustic resonance are summarized previously. A detection method is designed for 4kW electronic power system. Experimental results confirm this method to be a valuable tool. It verifies the correctness and effectiveness of detection circuit.3 By analyzing the causes of acoustic resonance, all sorts methods of acoustic resonance suppression are introduced whether energy perspective or frequency perspective. Considering experiment condition, a suppression circuit used to eliminate acoustic resonance is designed for 4kW electronic power system. This circuit employs frequency modulation technology, and then it is tested in 4kW electronic ballast platform. The results show that the frequency modulation can effectively suppress acoustic resonance of HID lamp.Finally, fluorescent electronic ballast is studied in the thesis. It is introduced that a typical half-bridge topology of fluorescent electronic ballast. The principle of operation is analyzed, laying emphasis on the timing sequence diagram in steady state. Besides, the resonance tank is analyzed under starting and steady state. Through experiment and simulation to 70w fluorescent, the correctness of the analysis is verified.This paper is greatly supported by National Nature Science Foundation of China, Project Name:The stability of high frequency resonant transformation system for HID lamps.(No.60672009).