Title:
ELECTRONIC BALLAST WITH CLOSED LOOP CONTROL USING COMPOSITE CURRENT AND VOLTAGE FEEDBACK AND METHOD THEREOF
Document Type and Number:
WIPO Patent Application WO2007050047
Kind Code:
A8
Abstract:
An electronic control system especially for non-linear loads, such as high pressure sodium (BPS) lamps, includes an active power factor correction circuit (APFC). The system provides a power factor correction of above .95; total harmonic distortion (THD) below 5%; lamp crest factor (LCF) close to unity; efficient power consumption and reliable open circuit voltage (OCV) under all power line conditions. A ballast would include integrated circuits (ICs) (16) and a four-arm transistor (11-14) bridge (15) which is directly driven by integrated circuits (16). The bridge (15) generates reversal of polarity to the load. An approximate average current feedback is derived from a load current. A resistor divider in parallel with the load provides voltage feedback. The average current feedback and voltage feedback are added together to provide an approximation of power consumed by the load, without the complex circuitry required for a true power feedback of current multiplied by voltage. That composite feedback signal is transmitted to the integrated circuit (IC) (16) which compares it with an internal reference voltage and which adjusts the IC output to minimize the error.
Inventors:
POWERS CHARLES JR (CN)
FELDSTEIN ROBERT S (US)
FELDSTEIN ROBERT S (US)
Application Number:
PCT/US2005/029752
Publication Date:
June 07, 2007
Filing Date:
August 16, 2005
Export Citation:
Assignee:
ARGENT ELECTRIC (US)
POWERS CHARLES JR (CN)
FELDSTEIN ROBERT S (US)
POWERS CHARLES JR (CN)
FELDSTEIN ROBERT S (US)
International Classes:
G05F1/00; H05B37/02; H05B39/04; H05B41/36
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