Split Winding Repeater for Wireless Power Through Lossy Metals
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Solution Overview
Problem
Wireless transfer of electrical power through lossy materials like stainless steel, copper, and aluminum is hindered due to the skin effect, which prevents electromagnetic waves from penetrating through the thickness of these metals, posing challenges in recharging medical device batteries in sterile environments without contaminating them.
Innovation Solution
A wireless electrical energy repeater circuit comprising a first inductive winding portion connected in series with a second winding portion, with at least one capacitor to resonate at a specific frequency, allowing energy to pass through lossy materials by acting as a uniform resonator and using intermediate ferrite substrates to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless electromagnetic energy transfer is used to power medical devices through sterile barriers, then physical contact is reduced and contamination risk is minimized, but lossy materials like metals block the electromagnetic waves due to the skin effect
Solution Approach 1:
The wireless power transfer system is segmented into multiple resonant circuits distributed across the sterile barrier. Each segment acts as an independent resonant unit that can be tuned to the operating frequency, allowing the electromagnetic energy to be transferred through the barrier by hopping between segments rather than penetrating the entire barrier at once. This segmentation overcomes the skin effect limitation by creating multiple transmission paths through the lossy material.
Solution Approach 2:
Ferrite materials are introduced as intermediary substances between the electromagnetic waves and the metal barrier. These ferrite intermediaries have magnetic properties that allow them to guide and transmit the electromagnetic energy while being less affected by the skin effect. The ferrite acts as a mediator that converts the blocked electromagnetic interaction into a transmissible form through the metal barrier.
2Power
If traditional electrical power cables are used to connect devices to power outlets, then reliable power delivery is achieved, but device movement is restricted and cord entanglement occurs
Solution Approach 1:
The mechanical power delivery system (electrical cables and connectors) is replaced with a wireless electromagnetic field-based power transfer system. The resonant inductive coupling mechanism transfers power through magnetic fields without requiring physical contact or cable connections. This substitution eliminates the mechanical constraints of cables while maintaining reliable power delivery through resonant energy transfer between transmitter and receiver coils.
3Duration of action of moving object
If batteries are removed from sterile devices for recharging, then power source can be replenished, but sterile field is breached and contamination risk increases
Solution Approach 1:
The battery-powered device is equipped with a wireless power receiver that enables it to recharge itself while remaining in the sterile field. The resonant inductive coupling system allows the device to receive power wirelessly from an external transmitter without requiring battery removal or physical connection to non-sterile power sources. This self-service capability maintains the sterile barrier integrity while extending operational duration.
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
Enables efficient and contamination-minimized wireless power transfer through metals by resonating at a frequency that allows energy to exit the circuit on the opposite side, effectively powering medical devices and recharging batteries without physical contact, thus reducing infection risks.
Implementation Method 1
electrical energy is transferred wirelessly between two resonators that are tuned to resonate at about the same frequency
Implementation Method 2
two resonators that are tuned to resonate at about the same frequency
Implementation Method 3
an oscillating magnetic field 16 between the two is created that enables transfer of electrical energy therebetween
Implementation Method 4
penetration of the waves through some metallic materials, such as stainless steel, copper, nickel and aluminum, may be hindered by the skin effect of the metal
Data Source
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AI summary
A circuit for transferring wireless electrical energy through a lossy material is described. The circuit comprises a first inductive winding portion connected electrically in series to a second inductive winding portion and at least one capacitor. Interaction of the first or second inductive winding portions with an electromagnetic field emanating from an electrical power source causes electrical energy to be induced within the circuit. The first inductive winding portion is preferably positionable adjacent a first sidewall of a lossy material and the second inductive winding portion is preferably positionable adjacent the second and opposite sidewall of the lossy material. At least one intermediate substrate composed of a ferrite material is preferably positioned between the first and second inductive winding portions as a shield that minimizes electromagnetic field interference.