The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 08, 2011
Filed:
Mar. 13, 2008
Klaus Seidler, Uetersen, DE;
Joerg Engelhardt, Hamburg, DE;
Klaus Seidler, Uetersen, DE;
Joerg Engelhardt, Hamburg, DE;
ESW GmbH, Wedel, DE;
Abstract
The invention relates to a method and to an arrangement for harmonic-wave suppression in AC voltage-operated PTC heaters, especially in frequency-stable and frequency-variable alternating-voltage networks in aerospace applications. The problem of harmonic-wave suppression for AC voltage-operated PTC heaters, in which the harmonic waves are suppressed by superimposing a correction current, which permits a simple and economical generation of the harmonic-wave suppression signal, is solved according to the invention by generating a correction current in a correction current circuit arranged parallel to the PTC heater using an ohmic resistor (). The correction current is generated and additively superimposed exclusively for suppressing the third harmonic of the heating current of the PTC heater.