Feedback control of TET system with variable coupling coefficients for a novel artificial anal sphincter

Area of Science:

• Biomedical Engineering
• Electrical Engineering
• Medical Devices

Background:

• Severe fecal incontinence presents a significant clinical challenge.
• Existing treatments may be invasive or lack consistent efficacy.
• Advancements in implantable devices require reliable wireless power solutions.

Purpose of the Study:

• To develop and validate a stable wireless power system for an intelligent artificial anal sphincter system (AASS).
• To address power delivery challenges in transcutaneous energy transfer systems (TETS) under variable coupling conditions.
• To ensure consistent power supply for a medical device treating fecal incontinence.

Main Methods:

• Developed a closed-loop variable-frequency controller to stabilize output voltage in a TETS.
• Derived voltage gain characteristics for a voltage-fed series-tuned TETS.
• Utilized numerical analysis for control rules relating operating frequency and output voltage.
• Constructed and tested a prototype TET charging system with coupling variations (0.12-0.42).

Main Results:

• The TETS output voltage was maintained at a constant 7V across the tested coupling coefficient range.
• Switching frequency regulation ranged from 271.4 to 320.5 kHz.
• The controller achieved a maximum end-to-end power efficiency of 67.5% at 1W.
• Theoretical analysis was experimentally verified.

Conclusions:

• The proposed controller effectively stabilizes TETS output voltage under varying coupling conditions.
• This technology enables reliable wireless power for implantable devices like the AASS.
• The system demonstrates potential for improving the treatment of severe fecal incontinence.