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:
Jan. 11, 2011
Filed:
Feb. 06, 2009
Michael Craig Stevens, Cambridge, GB;
Alexander Charles Knill, Cambridge, GB;
John Robert Dunton, Suffolk, GB;
Michael Craig Stevens, Cambridge, GB;
Alexander Charles Knill, Cambridge, GB;
John Robert Dunton, Suffolk, GB;
Access Business Group International LLC, Ada, MI (US);
Abstract
An inductive power transfer system comprises a primary unit, having a primary coiland an electrical drive unitwhich applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device, separable from the primary unit and having a secondary coilwhich couples with the field when the secondary device is in proximity to the primary unit. A control unitcauses a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unittakes one or more measures of such energy decay during the measurement period. In dependence upon said one or more energy decay measures, the control unit controls the electrical drive unit so as to restrict or stop inductive power transfer from the primary unit.