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:
Oct. 07, 2014
Filed:
Oct. 15, 2013
Sma Solar Technology Ag, Niestetal, DE;
SMA Solar Technology AG, Niestetal, DE;
Abstract
When determining a fault current portion Iin a differential current i(t) measured by an inverter, an AC voltage u(t) applied to an AC output of the inverter is measured and a periodic reference function y(t) of alternating sign is generated as a function of the measured AC voltage u(t) in order to determine an AC fault current portion Iin the differential current i(t). The differential current i(t) is multiplied by the periodic reference function y(t), and the product of the differential current i(t) and the reference function (y(t)) is averaged over an integral number of periods of the reference function y(t). The reference function y(t), at least for one operating state of the inverter, is generated with a predefined phase offset with respect to the measured AC voltage u(t) and/or with a frequency which is an integer multiple of the frequency of the measured AC voltage u(t).