Coupling analysis of transcutaneous energy transfer coils with planar sandwich structure for a novel artificial anal sphincter

This paper presents a set of analytical expressions used to determine the coupling coefficient between primary and secondary Litz-wire planar coils used in a transcutaneous energy transfer(TET) system. A TET system has been designed to power a novel elastic scaling artificial anal sphincter system(ES-AASS) for treating severe fecal incontinence(FI), a condition that would benefit from an optimized TET. Expressions that describe the geometrical dimension dependence of self- and mutual inductances of planar coils on a ferrite substrate are provided. The effects of ferrite substrate conductivity, relative permeability, and geometrical dimensions are also considered. To verify these expressions, mutual coupling between planar coils is computed by 3D finite element analysis(FEA), and the proposed expressions show good agreement with numerical results. Different types of planar coils are fabricated with or without ferrite substrate. Measured results for each of the cases are compared with theoretical predictions and FEA solutions. The theoretical results and FEA results are in good agreement with the experimental data.

A novel artificial anal sphincter system based on transcutaneous energy transmission

For controlling anal incontinence,a new artificial anal sphincter system (AASS) with sensor feed-back based on transcutaneous energy transmission is developed.The device mainly comprises an artificialanal sphincter (AAS),a wireless power supply subsystem,and a communication subsystem.The artifi-cial anal sphincter comprises a front cuff and a sensor cuff placed around the rectum,a reservoir sited inabdominal cavity and a micropump controlling inflation and deflation of the front cuff.There are two pres-sure sensors in the artificial anal sphincter.One can measure the pressure in the front cuff to clamp therectum,the other in the sensor cuff can measure the pressure of the rectum.Wireless power supply sub-system includes a resonance transmit coil to transmit an alternating magnetic field and a secondary coil toreceive the power.Wireless communication subsystem can transmit the pressure information of the artifi-cial anal sphincter to the monitor,or send the control commands to the artificial anal sphincter.A proto-type is designed and the basic function of the artificial anal sphincter system has been tested through ex-periments.The results demonstrate that the artificial anal sphincter system can control anal incontinenceeffectively.