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. 11, 2003
Filed:
Nov. 06, 2001
Orrin B. West, Canton, MI (US);
Ballard Power Systems Corporation, Dearborn, MI (US);
Abstract
A device inserted between a grounded poly-phase external voltage source and a load providing low insertion loss for differential mode currents and high insertion loss for ground currents. The device receives voltages from the grounded poly-phase external voltage source over atone or more voltage lines. The voltages contain common mode voltages. A filter connected to each of the voltage lines reduces the ground current from the load. A summing block adds the voltages from each of the voltage lines to generate a total common mode voltage. A ground referenced controlled voltage source generates a cancellation voltage equal to the total common mode voltage in response to the generation of total common mode voltage. The total common mode voltage is injected into the filter and substantially reduces the common mode voltage on each voltage line thereby substantially reducing the ground currents associated with each common mode voltage on each voltage line.