Research And Design On The150W Metal Halide Lamps Digital Electronic Ballast

In the lighting territory, the high intensity discharge lamp is widely used as the energy-saving lighting source. Especially, the metal halide lamp is priority choice in the green lighting project for its high light efficiency, nice coloration, energy-saving and long lifetime. Comparing to the inductive ballast, the electronic ballast is more meaningful in energy conservation, lighting quality improvement and green lighting advancement.After study of the MHL features and the technology of the electronic ballast, the requirements for the ballast are proposed in the dissertation. During the hardware design process, a three-stage topology structure is proposed to meet its demand. That is, the first stage is PFC circuit based on the Boost topology, the second stage is power control circuit based on the Buck topology, and the third stage is full bridge inverter generating the low frequency square wave. By the theoretical analysis and simulation research on the hardware circuit, the proposed design in the dissertation simplify the circuit and easy the control strategy. Also, the parameter of the electronic ballast is shown in the dissertation.For the control of the MHL, as the digital control features the less BOM and more flexible control compared to the analogue control, the MC56F8013from freescale is adopted as the DSP IC to achieve safe ignition, smooth power increase and constant power control. According to the features of the MHL, the method of using the PFC output voltage and the average input current of Buck to achieve the constant power control is adopted in the dissertation. By digital control, the MH lamp is ignited safely and reliably. Then the MH lamp’s power increase smoothly during the transition process, and also, the protection in the proposed design will response to the abnormal situation, if it occurs.At last, the test results of the150W electronic ballast prototype are shown in the dissertation and it’s clear that the proposed design meet the demand of the requirement given before, and the lighting effect is good without flicking.