A novel single stage single switch PFC converter with constant power control for ballast for medium HID lamps

A novel single stage single switch PFC (S/sup 4/-PFC) AC/DC converter is presented in this paper. A direct-energy-forward method and a constant power control strategy are employed to achieve low THD and proper output characteristics over a wide range of load (10%-full load) and input mains voltage (170 V-260 V) simultaneously with a low DC bus voltage well below 450 V. It is suitable for electronic ballasts for medium power HID lamps.