High frequency electronic ballast with reactive power compensation
A lamp ballast circuit which provides a magnetizing inductance to a lamp ballast circuit transformer. A DC voltage and current supply source energize a pair of transistors which provide an AC voltage and current. The transformer includes a primary winding that receives the AC voltage and current. At least one lamp is coupled to the transformer secondary winding via a capacitor. The circuit has an optimal magnetizing inductance such that the transformer input voltage and current are substantially in phase with each other, thereby substantially reducing or eliminating the reactive power transferred through the output transformer. In a preferred embodiment, the magnetizing inductance, L102, is given as:L&khgr;=[1&#8722;(&ohgr;sC1R1)2]/n2&ohgr;s2C1,wherein &ohgr;s is an operating frequency, C1 is the capacitance of the capacitor, R1 is the resistance of the at least one lamp, and n is the secondary-to-primary side turns ratio of the transformer.
Koninklijke Philips Electronics N.V.
H H
H05B H02M
inventional inventional
Chin Gert W.
Chang Bruning