Transcutaneous energy transfer system including alarm

A ventricular assist device comprising a transcutaneous energy transfer system that comprises:

• an internal component adapted to be disposed within a body of a patient, the internal component comprising:
• an internal coil;
• an internal power source electrically connected to the internal coil and adapted to receive power from the internal coil;
• an implantable device electrically connected to the internal power source;
• and
• internal circuitry comprising an internal transceiver adapted to send and receive signals representative of one or more parameters relating to operation of the internal component;
• and
• an external component adapted to be disposed outside the body of the patient, the external component comprising:
• an external coil;
• an external power source electrically connected to the external coil;
• and
• external circuitry electrically connected to the external power source and the external coil, wherein the external circuitry comprises an external transceiver and an external controller, wherein the external transceiver is adapted to communicate with the internal transceiver and send and receive the signals representative of the one or more parameters relating to operation of the internal component, and wherein the external controller is electrically connected to the external transceiver and adapted to:
• determine whether the internal coil is electromagnetically disconnected from the external coil;
• if the internal coil is electromagnetically disconnected from the external coil, then:
• determine a reconnection time threshold based upon at least one of a power transfer efficiency value between the internal coil and the external coil, a charge state of the internal power source, or a power consumption value of the implantable device;
• and
• output a charging alarm if a time interval when the internal coil is electromagnetically disconnected from the external coil exceeds the reconnection time threshold.

A method of outputting a charging alarm for a transcutaneous energy transfer system, the method comprising:

• determining that an internal coil of an internal component of the transcutaneous energy transfer system is electromagnetically disconnected from an external coil of an external component of the transcutaneous energy transfer system;
• determining a reconnection time threshold based upon at least one of a power transfer efficiency value between the internal coil and the external coil, a charge state of an internal power source of the internal component that is electrically connected to the internal coil, or a power consumption value of an implantable device of the internal component that is electrically connected to the internal power source;
• and
• outputting the charging alarm based on a time interval when the internal coil is disconnected from the external coil exceeding the reconnection time threshold.