Power flow control of TET system for a novel artificial anal sphincter system

This paper presents an adaptive transcutaneous energy transfer system (TETS) integrated with a novel elastic scaling artificial anal sphincter system (ES-AASS) for treating severe faecal incontinence (FI). The ES-AASS is based on a novel executive mechanism that uses a spring scalable structure to clamp the rectum. To deliver the correct amount of power (i.e. to match the load demand under variable coupling conditions or different operation stages of the implanted device) for internal battery charging and ensure safety for the human body, theoretical analysis was conducted as a control rule with respect to the relationship between the phase of driver signals and output voltage. An easy regulating procedure to stabilize output voltage with a phase shift controller is also presented. To validate the phase control rules, a prototype of the TETS was constructed and its performance was validated across the whole coupling coefficient range (0.09 ∼ 0.29) as well as load resistance (50 ∼ 120 Ω). The results show that the output voltage of the secondary side can be maintained at a constant 7 V with a phase regulation range of 78.7-178.2° and the proposed controller has reached a maximal end-to-end power efficiency of 74.2% at 1 W.