Tracking and Dynamic Tuning of a Wireless Powered Endoscopic Capsule

Area of Science:

• Medical Devices
• Wireless Power Transfer
• Biomedical Engineering

Background:

• Endoscopy capsules require reliable power for internal electronic devices.
• Inductive wireless power transfer (WPT) offers a potential solution for powering such miniaturized systems.
• Maintaining stable power delivery during capsule movement and misalignment is a significant challenge.

Purpose of the Study:

• To present an inductive wireless power transfer system for powering endoscopy capsules.
• To address challenges of misalignment and maintain consistent power delivery.
• To optimize power transfer and prevent overheating within the capsule.

Main Methods:

• A receiver with three coils in quadrature was designed for the capsule.
• The system tracks magnetic coupling coefficient variations to compensate for misalignment.
• Control is achieved by adjusting capacitance in the matching network and voltage source frequency.
• Power is limited by adjusting the voltage source magnitude to prevent overheating.

Main Results:

• Consistent power delivery of 100-130 mW was achieved at the load.
• Effective power transfer was demonstrated even at low magnetic coupling coefficients (k ranging from 1.7 × 10-3 to 3.5 × 10-3).
• The system successfully compensated for capsule translations and revolutions within the transmitter coil (380 mm diameter).

Conclusions:

• The proposed WPT system reliably powers endoscopy capsules.
• The tracking control mechanism ensures stable power delivery despite positional variations.
• This technology enables robust power solutions for in-vivo capsule-based medical devices.