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:
Mar. 11, 1997
Filed:
Jul. 31, 1995
Gerald L Smith, Torrance, CA (US);
MAGL Power Inc., Torrance, CA (US);
Abstract
A device for detecting the occurrence of a dc current fault in the dc feed bus of a solid state power inverter bridge. The device uses a standard, available dc shunt which is connected in the dc feed bus and which produces an ac component in its output as well as dc as a result of the PWM action of the inverter bridge. An isolation transformer and an absolute value detector process the shunt output signal and present the resulting dc signal to a digital comparator after being summed with a voltage trip level. The comparator will output a low signal indicating a fault current if the instantaneous dc component connected from the isolation transformer is higher than the comparator input trip level. The fault detection action of the invention sensor is virtually instantaneous and can be used to shut down the solid state switches in the bridge and protect them from possible damage.