Sense Coil Phase Angle Detection for Implantable Charger Alignment
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Solution Overview
Problem
Existing wireless external chargers for implantable medical devices face inefficiencies in power transmission due to poor alignment between the charger and the implant, leading to reduced coupling and longer charging times, which can result in increased power expenditure and potential patient safety risks.
Innovation Solution
The use of a sense coil in conjunction with control circuitry to determine the phase angle between the induced signal and the drive signal, allowing for precise alignment and centering of the charging coil with respect to the implantable medical device, thereby optimizing coupling and reducing misalignment indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless power transmission is used to charge the implantable medical device, then charging convenience is improved, but alignment precision deteriorates leading to reduced coupling efficiency
Solution Approach 1:
The system uses a sense coil to detect the position of the implantable device during wireless charging and provides feedback to control circuitry. This feedback mechanism enables real-time monitoring and adjustment of alignment, resolving the contradiction by maintaining charging convenience while improving alignment precision through active detection and correction.
Solution Approach 2:
The patent replaces mechanical alignment systems with electromagnetic field-based detection using a sense coil. This substitution allows for non-contact, wireless position detection that works seamlessly with the wireless power transmission system, maintaining ease of operation while achieving precise alignment through electromagnetic sensing rather than mechanical means.
2Productivity
If alignment detection is added to the wireless charger, then coupling efficiency is improved, but device complexity increases
Solution Approach 1:
The sense coil serves multiple functions: it detects the position of the implantable device for alignment purposes and also contributes to the overall wireless power transmission system. This multi-functionality approach improves charging efficiency through better alignment while minimizing the increase in device complexity by reusing existing electromagnetic components for dual purposes.
Solution Approach 2:
The sense coil acts as an intermediary element that provides position information without requiring complex imaging or multiple sensor arrays. This simple intermediary approach enables alignment detection and improved coupling efficiency while adding minimal complexity to the wireless charging system.
3Measurement precision
If phase angle detection is used to determine position, then alignment accuracy is improved, but power consumption increases
Solution Approach 1:
The system uses the electromagnetic field already present during wireless power transmission to perform position detection via phase angle measurement of the sense coil signal. This self-service approach allows the charging system to simultaneously provide power and position information without requiring separate power sources or additional energy-intensive detection systems, thus improving position detection accuracy while minimizing additional power consumption.
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 solution enhances charging efficiency by ensuring higher coupling between the charging coil and the implantable medical device, reducing charging time and power consumption, and improving patient safety by minimizing the risk of overheating or injury.
Implementation Method 1
a sense coil, wherein the sense coil is configured to be induced by the magnetic field with an induced signal affected by a position of the charging coil with respect to the IMD
Implementation Method 2
a charging coil configured when energized by a drive signal to produce a magnetic field to wirelessly provide energy to the IMD
Data Source
Figure 1A~1C
Figure 2~3
Figure 4A~4C
AI summary
A charging system for an Implantable Medical Device (IMD) is disclosed having a charging coil and one or more sense coils preferably housed in a charging coil assembly coupled to an electronics module by a cable. The charging coil is preferably a wire winding, while the sense coils are preferably formed in one or more traces of a circuit board. One or more voltages induced on the one or more sense coils can be used to determine a phase angle between the voltage and a driving signal for the charging coil. The determined phase angle can then be used to determine the position of the charging coil relative to the IMD. Additionally, more than one parameter (phase angle, magnitude, resonant frequency) may be determined using the voltage may be used to determine position, including the radial offset and depth of the charging coil relative to the IMD.