Method to improve Current Wave Forms and Power Factor in the Continuous Dimmer Circuit for High-Pressure Mercury Discharge Lamps

Abstract

Concerning the continuous dimmer circuit with a TRIAC for a high pressure mercury discharge lamp, the authors propose an new operating circuit through which current is nearly sinusoidal and runs with power factor close to 100%. We connect the by-pass circuit to the tap at the point of near the power source side. The self-inductance employed here is larger than the one for conventional ballast. It is shown that the operating circuit, of which the input current is sinusoidal with power factor of 100%, is realized, by adjusting the circuit constant, self-inductance L, self-inductance of choke coil of by-pass circuit Lb and capacitance Cb to appropriate values for each firing angle of TRIAC.