A Portable Transmitter for Wirelessly Powering a Ventricular Assist Device Using the Free-Range Resonant Electrical Energy Delivery (FREE-D) System

Wireless power technology offers an exciting opportunity to eliminate the wired connections that power electronic devices. In the context of implanted medical devices, wireless power, together with wireless data communication, can eliminate transcutaneous (skin-penetrating) cables altogether. Ventricular assist devices (VADs) are implanted heart pumps that currently rely on transcutaneous cables for transport of power and data; however, these transcutaneous cables are a leading source of infection and re-hospitalization that negate the intended benefits of VAD implants. By eliminating the transcutaneous driveline, wireless power can eliminate the leading cause of VAD complications. Nearly one million Americans have heart problems that lead to hospitalization, and 80,000 of them experience heart failure. Integrating wireless power technology into VADs will enable VAD therapy to become a more viable option for heart failure patients than heart transplants. The Free-range Resonant Electrical Delivery (FREE-D) system uses magnetically coupled resonators to efficiently transfer power across meter distances to a VAD implanted in the human body. For use inside the patient’s home, several strategically placed transmit resonators will be situated around the household so that the implanted receiver is within an all-encompassing space where it can constantly receive power as the patient moves around. Naturally, each transmit resonator will be directly connected to an electrical outlet [1-4]. To eliminate the constraints of staying inside the home to be in range of the transmitters, a battery-powered transmitter can power the portable FREE-D system, which enables full patient mobility outside the household. An overview of both the in-home FREE-D system and the portable FREE-D system are presented in this chapter. Also, an adaptive frequency tuning method is integrated with the battery-powered inverter to allow for maximum power transfer efficiency over a range of separation distances and angular orientations between the transmit and receive resonators. Measured results show the continuous operation of a VentrAssist centrifugal pump VAD [5] using the portable FREE-D system with a coil-to-coil wireless power transfer efficiency around 90%.