Research on dimming control method of electronic ballast for the automotive HID headlight

It is the purpose of this paper to explore the problem of dimming the HID lamp used in the automotive headlight system. To investigate the relationship between the lamp power and control parameters, a power-dependent HID lamp model is established in this paper. The two methods, dynamic duty-ratio control and dynamic bus voltage control, are analyze and applied in the system. The dynamic bus voltage control which can be realized according to the structure of controller is stressed in this paper. The simulation results and experimental results give the difference between the different dimming control methods.