Patent ID: 8612013

Claim:
A system comprising an electrically powered medical device adapted to be implanted in a patient, in which system the medical device comprises an internal energy receiver arranged to power the medical device, the system also comprising an external energy source adapted to be located externally to the patient for wireless supply of energy to said internal energy receiver, the external energy source being equipped with a primary coil from which the external energy source is arranged to transmit said energy inductively to a first secondary coil in the energy receiver, the system being arranged to determine by measurements one or more parameters related to a first coupling factor between the primary and the first secondary coil, in which system the external energy source is adapted to transmit a first amount of energy to the energy receiver for enabling the medical device to detect information related to the first coupling factor, the system is adapted to wirelessly send feedback information related to said first coupling factor to the external energy source with the external energy source being arranged to receive said feedback information from the medical device and in that the external energy source is adapted to perform a predetermined action based on said feedback information, and wherein the system is adapted to let the first secondary coil be substantially without electrical load when measuring the first coupling factor.