Power Control Strategy of Electronic Ballast for HID Lamps

This paper proposed a power control strategy of the general three-stage electronic ballast (Eballast) for HID lamps. This control strategy utilizes the dc input current as the power level signal. Since the input of the DC/DC stage is constant, the control of the input current ensures the control of the lamp power. This approach is more feasible for digital controlled Eballast. As it only needs one ADC and eliminates power calculation procedure, this strategy decreases the cost and make the use of low-end MCU possible. The simulation and experiments based on the prototype of digital controlled Eballast for 250W MH lamps validated the proposed control strategy