Patent ID: 8463394

Claim:
A method for controlling transmission of wireless energy supplied to an electrically operable medical device implanted in a mammal patient, the method comprising the steps of: transmitting wireless energy from an external energy source by means of a primary coil located outside the patient, and receiving the transmitted wireless energy inductively in an internal energy receiver by means of a secondary coil located inside the patient, to directly or indirectly supply received energy to the medical device, receiving by an electronic circuit in the external energy source feedback information sent from inside the patient, comparing the feedback information with the amount of energy transmitted by the external energy source, wherein the feedback information is related to the amount of energy being received in the internal energy receiver, analysing by an analyzer in the electronic circuit the amount of energy being transmitted, using the received feedback information related to the amount of energy received in the internal energy receiver, determining a special energy balance by comparing the amount of transmitted energy and the feedback information related to the amount of received information, thus the feedback information is related to a coupling factor between the primary coil and the secondary coil, obtaining information about the coupling factor between the coils, calibrating the system for: a) finding an optimal place for the external coil in relation to the internal coil, and b) optimizing energy transfer, comparing the amount of energy transferred with the amount of energy received, detecting an energy balance after said calibration of the special energy balance being at least one of: a difference between the total amount of energy received by the internal energy receiver and the total amount of consumed and stored energy, being directly or indirectly measured over time, and an energy reception rate in the internal energy receiver corresponding to the total rate of energy consumption and storage of the apparatus, determining the energy balance based on at least one of: a detected change in the difference in the total amount of energy received by the internal energy receiver and the total amount of consumed and stored energy, and a detected change in the difference between the energy reception rate in the internal energy receiver and the total rate of energy consumption and storage, controlling the transmission of wireless energy from the external energy source, based on the determined energy balance to optimize energy transfer, during energy transfer.