Inductive Power Link for Implantable Devices
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Solution Overview
Problem
Implantable medical devices with conductive casings, such as titanium, face challenges in power transfer due to shielding and heat generation, leading to inefficiencies and potential damage from eddy currents, especially when using inductive links at higher frequencies.
Innovation Solution
The implementation of inductively coupled elements with magnetically permeable cores, where one element is inside the conductive casing and the other is external, operating at lower frequencies to minimize losses and allow efficient power transfer across the conductive casing, reducing heat generation and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inductive links operate at higher frequencies to improve power transfer speed, then power transfer efficiency improves, but heat generation and eddy current losses increase
Solution Approach 1:
The patent changes the operating frequency parameter to a lower range (e.g., 50-500 Hz) to reduce eddy current losses and heat generation in the conductive casing, while compensating for the reduced power transfer speed through other means such as increased coil turns or optimized magnetic coupling
2Adaptability or versatility
If implanted coils are positioned inside the conductive casing to achieve totally implanted devices, then aesthetic advantages and practical benefits are achieved, but the conductive casing shields and absorbs incoming power
Solution Approach 1:
The patent introduces magnetic shielding materials or flux guide structures as intermediaries between the external power source and the implanted coil, allowing the conductive casing to be positioned between the coils while still permitting effective magnetic coupling through controlled flux paths
3Loss of energy
If conventional inductive links are used with conductive casings, then power transfer is achieved, but feedthroughs are required which compromise the sealed structure
Solution Approach 1:
The patent extracts the power transfer function from the mechanical structure by using entirely inductive coupling, eliminating the need for physical feedthroughs that would compromise the hermetic seal of the implantable device casing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances power transfer efficiency, reduces battery size and charging time, minimizes heat generation, and eliminates the need for feedthroughs, while maintaining a fully sealed and biocompatible system, suitable for various implantable devices like cochlear implants and pacemakers.
Implementation Method 1
first and second inductively coupled elements each comprising an inductive coil disposed about a magnetically permeable core; wherein the first element is disposed in the casing, and the second element is disposed external to the casing, and wherein the first and second elements provide transfer of power across the at least partially conductive casing
Implementation Method 2
each comprising an inductive coil disposed about a magnetically permeable core
Data Source
AI summary
A power transfer system for an implanted device, such as an implanted medical device. The implanted device and a power transfer device each include a coil with a magnetically permeable core, so that operatively the coils are magnetically coupled, so as to improve the efficiency of power transfer. The coil resides in an electrically conductive implant case.