Real-time Alignment Sensing for Optimized Inductive Charging of Medical Implants

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Implantable Devices

Background:

• Inductive wireless power transfer (WPT) is crucial for medical implants but suffers from energy inefficiencies.
• Misalignment between external and internal coils significantly reduces WPT efficiency and can cause tissue heating.
• Existing alignment solutions require implant communication, increasing hardware and power demands.

Purpose of the Study:

• To develop a real-time alignment sensor for inductive WPT systems.
• To enable implant location and orientation detection without communication from the implant.
• To optimize WPT alignment and improve energy efficiency for medical implants.

Main Methods:

• Developed an external-side alignment sensor for inductive WPT.
• Measured external magnetic field strength across various implant positions.
• Analyzed magnetic field measurements for dependence on implant proximity and orientation.

Main Results:

• External magnetic field strength measurements showed clear dependence on implant proximity.
• Detected implant-dependent minima in monitor coil measurements.
• Demonstrated preliminary evidence of real-time lateral orientation detection via primary-side field sensing.

Conclusions:

• Primary-side field sensing can detect implant lateral orientation in real-time during WPT.
• This method optimizes alignment without requiring additional circuitry within the implant.
• The technology can reduce implant power load and simplify user alignment procedures.