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. 13, 1979
Filed:
Jun. 30, 1978
John Rosa, Penn Hills, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
Disclosed is a force commutated static switch composed of inverse parallel connected thyristors. A bilateral commutation circuit is connected across the thyristors. The commutation circuit includes a switched capacitor which, during a current commutation interval, provides the dual functions of contributing to the current commutation operation and of acting as a current source for one of the thyristors. The capacitor discharge current interacts with the intrinsic resistance of the thyristor to provide a relatively low forward voltage drop which is a reverse voltage drop for the other thyristor. The low reverse voltage is known as soft biasing voltage. This voltage is utilized in conjunction with the most recently turned off thyristor to prevent reconduction thereof during the critical recovery time of the thyristor. The commutation circuit cooperates with its control circuit to provide an abort capability for its current limiting operation. Furthermore, the commutating circuit cooperates with its control circuit to eliminate repeated current reversals of the capacitor's discharge current.