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:
Nov. 10, 2009
Filed:
Feb. 08, 2008
Regine Mallwitz, Kassel, DE;
Regine Mallwitz, Kassel, DE;
SMA Technologie AG, Niestetal, DE;
Abstract
In a circuit apparatus for transformerless conversion of an electric direct voltage of a two-pole direct voltage source () connected to ground having a first voltage pole (+) and a second voltage pole (−) into an alternating voltage, hazardous capacitive leakage currents are avoided by connecting the direct voltage source () to ground and the DC-AC converter () is operated at a controlled intermediate circuit voltage, a DC-DC converter stage () being connected between the direct voltage source () and the DC-AC converter (), said DC-DC converter stage providing at its output a +/− voltage that is symmetrical with respect to the grounding point, two series-connected capacitors () having the same polarity and being connected to ground at their connecting point (V) and controlled are charged by two buck-boost choppers () connected one behind the other.