Concentric Primary Coils for Implantable Device Charging
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Solution Overview
Problem
The challenge lies in achieving precise alignment between the external antenna's primary coil and the implantable medical device's secondary coil for efficient transcutaneous energy transfer, as the center of the bulge created by the device may not correspond to the coil's center, leading to suboptimal charging efficiency.
Innovation Solution
A plurality of concentric primary coils are used in the external power source, with selection circuitry determining which coil provides the most efficient energy transfer to the secondary coil, allowing for a wider charging area and greater alignment flexibility, even if the primary coil is not perfectly aligned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a single primary coil is used in the external power source, then the device structure is simple, but the charging area is limited and alignment precision is difficult to achieve
Solution Approach 1:
The single primary coil is divided into multiple concentric primary coils with different diameters. Each coil can be independently activated based on the alignment requirements and charging efficiency needs, allowing the system to cover a wider charging area while maintaining manageable structural complexity through modular design
Solution Approach 2:
Multiple primary coils are arranged in a concentric nested configuration where smaller coils are positioned inside larger coils. This nesting approach maximizes the charging area coverage while minimizing the overall device footprint and structural complexity, as all coils share the same center point and can be integrated into a compact external power source housing
2Loss of energy
If the external antenna is precisely aligned with the secondary coil, then energy transfer efficiency is maximized, but the user experience is degraded due to difficulty in locating and securing the exact position
Solution Approach 1:
The system dynamically selects which primary coil to activate based on real-time coupling conditions and alignment status. Rather than requiring fixed precise alignment, the system can adaptively switch between different concentric coils to maintain optimal energy transfer efficiency even when the external antenna position varies within the expanded charging area
Solution Approach 2:
The system changes operational parameters by selecting different primary coils with varying diameters and inductance characteristics. This allows the energy transfer efficiency to be maintained across a range of positions by adjusting which coil is active, thereby decoupling the strict alignment requirement from the user positioning task
3Adaptability or versatility
If multiple concentric primary coils are used, then the charging area is expanded and alignment flexibility is improved, but the device complexity increases
Solution Approach 1:
The control system automatically determines which primary coil to activate based on coupling measurements and alignment detection, without requiring manual user intervention or complex external calibration. The system self-adjusts by selecting the appropriate coil configuration to achieve optimal energy transfer, thereby managing the increased device complexity through autonomous operation
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 ensures more efficient energy transfer and increased comfort for the user by allowing the system to automatically select the most efficient primary coil, enhancing the likelihood of successful charging despite potential misalignment.
Implementation Method 1
an internal power source, such as a battery, can be used for direct electrical power to the implanted medical device. When the battery has expended, or nearly expended, its capacity, the battery can be recharged transcutaneously, via inductive coupling from an external power source
Implementation Method 2
the battery can be recharged transcutaneously, via inductive coupling from an external power source temporarily positioned on the surface of the skin
Data Source
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AI summary
An external antenna with a plurality of concentric primary coils recharges an implantable medical device with a secondary coil when the primary coils are placed in proximity of the secondary coil. Selection circuitry determines which of the plurality of concentric primary coils has the most efficient coupling with the secondary coil and drive circuitry drives the selected primary coil with an oscillating current. During a recharge session, selection circuitry periodically checks at least some of the primary coils to determine whether the primary coil with the most efficient connection has changed. An antenna housing may hold the primary coils in a rigid planar relationship with each other or the primary coils may shift with respect to each other, forming a cup-shape around a bulge in the skin created by the implantable medical device.