Method and apparatus for supplying energy to a medical device

An apparatus configured to control wireless energy supplied to an electrically operable medical device adapted to be implanted in a mammal patient, comprising:

• an external energy source adapted to be located outside the mammal patient and comprising an external control unit adapted to be located outside the mammal patient, the external energy source being adapted to inductively transmit the wireless energy,
• an internal energy receiver located inside the patient and comprising an internal control unit, the internal energy receiver being adapted to inductively receive the wireless energy, the internal energy receiver being configured to directly or indirectly supply energy, received from the wireless energy, to the electrically operable medical device, and
• at least one stabilizing unit adapted to stabilize the energy received by the internal energy receiver before it is supplied to the electrically operable medical device,
• a control unit comprising one of the internal control unit and the external control unit,
• wherein the electrically operable medical device is adapted to transfer control information to the control unit,
• wherein the control information is related to an energy rate adapted to operate the medical device, said control information being adapted to be used to control the wireless received energy, and
• wherein the electrically operable medical device is adapted to consume or store or to consume and store, the wireless received energy after it has been stabilized in the at least one stabilizing unit of the apparatus,
• wherein the apparatus is configured to:
• firstly inductively transmit the wireless energy with a determined energy rate and secondly inductively transmit the wireless energy based on an energy balance, adapted to be determined by detecting a direction and rate of change in a current amount of accumulated energy in the at least one stabilizing unit, derived from at least one measured electrical parameter related to the accumulated energy in the stabilizing unit,
• wherein the apparatus is adapted to repeatedly measure, at certain intervals during ongoing energy transfer, an electric parameter for deriving the direction and rate of change in a current amount of accumulated energy in the stabilizing unit, and
• wherein the control information is related to the direction and rate of change in the current amount of accumulated energy in the at least one energy stabilizing unit.