A comparative study on dimming control methods for electronicballasts

摘要

This paper presents a comparative study on the performancencharacteristics between the variable switching frequency and variable DCnlink voltage control schemes for the dimming operation of electronicnballasts using a half-bridge series-resonant parallel-loaded inverter.nAttributes under investigations include (1) average input current of theninverter; (2) dimming characteristics; (3) variations of the filamentnpower and starting voltage throughout the dimming range; (4) dead timenboundaries for ensuring zero-voltage-switching in the inverter. Annapproximated fundamental-frequency model that includes thencharacteristics of the nonlinear lamp resistance and filament resistancenis used. Theoretical predictions are favorably verified with thenexperimental measurements in two 36 W Ballast-lamp systems