Sensor Systems Laboratory

FREED (Free-range Resonant Electrical Energy Delivery)

A tether-free Left Ventricular Assist Device (LVAD)

Summary

The Free-range Resonant Electrical Energy Delivery (FREE-D) wireless power system uses magnetically coupled resonators to efficiently transfer power across meter distances to an artificial heart, specifically a ventricular assist device (VAD) implanted in the human body. Previously, artificial heart pumps recieved power from a wire through the chest, limiting patient quality of life. In fact nearly 75% of the LVAD patient population experiences Exit Site Infection (ESI) within the first 6 months of implantation. The FREE-D system will cut down on cardiac patients' dangerous infections and improve quality of life.

The FREE-D system is based on the the Wireless Resonant Energy Link (WREL) wireless power transfer technology developed by the UW Sensor Systems Research Group. In the FREE-D system, transmit and receive resonators are tuned to resonate at a specific frequency. The resonator size and shape can be modified to accommodate application specifications, such as room size and patient body geometry. Additionally, an adaptive frequency tracking method can be implemented to achieve maximum power transfer efficiency – upwards of 70% – for nearly any angular orientation over a range of separation distances.

The transmit resonator can be placed in a wearable vest to transmit power to the implanted receive resonator encased in a biocompatible material. The resonators can accommodate variations in patient body types, and can rapidly adapt to any changes in coil orientation and misalignment. A backup battery can supply power to the LVAD in case the wireless power signal is unavailable.