New specification for the PFC controller in HID lamps electronic ballast

The ballast system and the lamp are subjected to the utility disturbances. In this way, HID lamps are very sensitive to voltage supply fluctuations that produce an effect on the human visual perception by changing the light emission, known as flicker. New design considerations and a control strategy for a two-stage ballast system, power factor correction (PFC) and inverter stage, for high intensity discharge (HID) lamps are presented along with a novel voltage fluctuation detection consistent with the maximum human light flickering perception. A correct actuation over the voltage loop of the PFC stage reduces the lamp sensitivity to flicker. In this case, a novel digital control technique for the PFC stage is used. It requires neither current sensor nor high speed analog-to-digital converter, which are two traditional bottlenecks for the implementation of digital controllers in such application.