Split Coil Uniform Magnetic Field for Implantable Device Charging
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Solution Overview
Problem
The existing method of determining alignment between an external charger and an implantable medical device (IMD) using coupling is inaccurate due to the non-uniform magnetic field generated by traditionally constructed coils, leading to incorrect indications of alignment and inefficient power transfer.
Innovation Solution
A split coil design is implemented in the external charger, where coil portions are positioned on either side of a substrate without radial current-carrying paths, resulting in a uniform magnetic field that allows for accurate alignment determination based on coupling and voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditionally constructed coil is used in the external charger, then the coil structure is simple and easy to manufacture, but the magnetic field generated is non-uniform leading to inaccurate alignment determination
Solution Approach 1:
The coil is divided into multiple segments or sections, each contributing to the overall magnetic field in a controlled manner. This segmentation allows the magnetic field to be more uniform across the charging area, improving alignment determination accuracy without requiring complex manufacturing processes.
Solution Approach 2:
Different portions of the coil are designed with specific current path characteristics that optimize the magnetic field distribution in local regions. By controlling the current paths to avoid radial configurations and instead use concentric or parallel paths, each section contributes uniformly to the magnetic field, enhancing overall measurement precision.
2Productivity
If a traditionally constructed coil is used in the external charger, then the coil design is straightforward, but power transfer efficiency is reduced due to misalignment errors
Solution Approach 1:
The coil is divided into multiple segments or sections, each contributing to the overall magnetic field in a controlled manner. This segmentation allows the magnetic field to be more uniform across the charging area, improving alignment determination accuracy without requiring complex manufacturing processes.
Solution Approach 2:
The coil design parameters such as turn density, wire gauge, and spatial arrangement are optimized to generate a uniform magnetic field. By adjusting these parameters, the system achieves better alignment detection and power transfer efficiency while maintaining manufacturability through standard coil winding techniques.
3Reliability
If radial current-carrying paths are used in the coil, then the coil construction is simple, but the magnetic field becomes non-uniform causing alignment indication errors
Solution Approach 1:
Different portions of the coil are designed with specific current path characteristics that optimize the magnetic field distribution in local regions. By controlling the current paths to avoid radial configurations and instead use concentric or parallel paths, each section contributes uniformly to the magnetic field, enhancing overall measurement precision.
Solution Approach 2:
The coil design parameters such as turn density, wire gauge, and spatial arrangement are optimized to generate a uniform magnetic field. By adjusting these parameters, the system achieves better alignment detection and power transfer efficiency while maintaining manufacturability through standard coil winding techniques.
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
The split coil design provides a more accurate indication of alignment, ensuring efficient power transfer and reducing the risk of misalignment errors, thereby improving the charging process for implantable medical devices.
Implementation Method 1
Power transmission from the external charger 50 to the IMD 10 occurs wirelessly and transcutaneously through a patient's tissue 25, via inductive coupling. Primary charging coil 52 in the external charger 50 is energized via charging circuit 64 with an AC current, Icharge, to create a magnetic charging field 66.
Data Source
AI summary
A charging system for an Implantable Medical Device (IMD) includes a split charging coil for generating a magnetic field to provide power to the IMD. The split charging coil includes a first coil portion and a second coil portion, each of which can be formed as a mechanical winding of an insulated conductor. The first and second coil portions are connected to each other in a way that substantially reduces or eliminates any current-carrying path that is routed radially with respect to the coil. As a result, the split coil produces a uniform magnetic field that enables a more accurate determination of alignment between the coil and the IMD than is available using traditional charging coils.