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:
Sep. 26, 1978
Filed:
Mar. 25, 1977
Donald Monroe Demarest, Wallingford, PA (US);
Edgar Frank Chandler, Media, PA (US);
General Electric Company, Philadelphia, PA (US);
Abstract
A thermal protection system is provided for a solid state valve that includes at least one representative thyristor having a junction and a heat sink system. The protection system comprises a thermal analog model whose electrical network dynamic electrical operating characteristics are electrically analogous to the thermal characteristics of the solid state valve for any given value of instantaneous load current supplied through the valve, which thermal characteristics include the heat transfer to cooling fluid capability characteristics of said representative thyristor including its heat sink system. A first electrical signal is derived which is representative of the value of the D.C. load current through said valve. A D.C. current to watts generation simulation network responsive to the first electric signal is provided for deriving an output electrical signal representative of the instantaneous value of the watts being dissipated within the junction of said representative thyristor for a given value of load current flowing through said junction. The watts-being-generated signal is applied to said thermal analog model and an output electric signal is derived from said thermal analog model which is representative of the temperature of said thyristor junction. The thermal analog model comprises an RC ladder network having the signal from the simulation network applied to one of its terminals. To another terminal of the ladder network is applied an electric signal representative of the instantaneous temperature value of the cooling fluid flowing over said solid state valve means and said heat sink system.