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. 30, 1999
Filed:
May. 05, 1997
Jeffery E Emmerich, Madison, WI (US);
Superconductivity, Inc., Middleton, WI (US);
Abstract
A method of delivering an optimized power level from a backup energy system to a load connected to a primary energy supply via a DC link and an inverter is provided. The method has the steps of: sensing a voltage of the DC link connected to the load; connecting a converter between the backup energy supply and the DC link; evaluating a rate of change of the voltage of the DC link; determining an estimate of the average load current using the rate of change of the DC link voltage; and controlling the converter using the average load current to switch the optimized power output from the backup energy supply to the load. In an embodiment, the step of determining an estimate of the average load current using the rate of change of the DC link voltage is performed in accordance with a formula I.sub.load =C.sub.DC link (dV.sub.DC link /dt). Also, the step of evaluating a rate of change of the DC link voltage is performed by representing a plurality of DC link voltage samples taken over time as points in an x-y coordinate system connected by a best fit line such that the slope of the line represents the rate of change of the voltage of the DC link. Further, the step of evaluating the rate of change of the DC link voltage may be implemented using a first plurality of serially connected sample and hold amplifiers having a second plurality of difference amplifiers selectively connected to the first plurality of sample and hold amplifiers and an operational amplifier summer connected to sum outputs of the difference amplifiers to produce an output. The output is used to control the converter for an optimized power level output switchover.