Wireless Power Transfer Resonant Frequency Tuning for Implantable Telemetry
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Solution Overview
Problem
Current wireless power transfer systems for implantable biomedical telemetry devices face challenges in providing continuous power to small animals like mice, especially due to loose coupling between primary and secondary coils, leading to inefficient power transfer and potential tissue damage from excessive power.
Innovation Solution
The development of devices and systems featuring a coil, tank capacitor, rectifier, and microcontroller that adjust resonant frequencies to optimize power transfer, using ferrite components to enhance coupling and prevent overheating, allowing for controlled power delivery to multiple animals in a single environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If wireless power transfer is used to power implantable telemetric devices in small animals, then continuous power supply is achieved, but loose coupling between primary and secondary coils leads to inefficient power transfer
Solution Approach 1:
The patent applies resonant coupling between primary and secondary coils at specific frequencies (e.g., 6.78 MHz) to enhance magnetic field coupling. By tuning the resonant frequencies of both coils to match, the system achieves efficient power transfer over loose coupling distances, resolving the contradiction between continuous power supply and energy loss.
Solution Approach 2:
The system dynamically adjusts operating parameters including frequency, coil orientation, and positioning to optimize power transfer efficiency. The microcontroller monitors power transfer conditions and modifies parameters in real-time to maintain efficient coupling despite animal movement, thereby sustaining continuous power supply without excessive energy loss.
2Measurement precision
If higher power is transferred to improve signal quality and data acquisition rate, then data quality improves, but tissue damage risk increases
Solution Approach 1:
The system incorporates feedback mechanisms where the microcontroller continuously monitors power transfer efficiency, coil coupling conditions, and device performance. Based on this feedback, the system dynamically adjusts the transmitted power level to maintain optimal data acquisition quality while preventing excessive power that could cause tissue damage. The feedback loop enables real-time optimization of the power-quality tradeoff.
Solution Approach 2:
The patent employs dynamic power adjustment capabilities where the transmitted power is not fixed but varies based on real-time conditions including animal movement, coil orientation, and data acquisition requirements. This dynamic approach allows the system to increase power when high-quality data is needed and reduce power when coupling is poor or safety thresholds are approached, resolving the contradiction between measurement precision and harmful effects.
3Device complexity
If fixed resonant frequency is used to simplify circuit design, then device complexity is reduced, but power transfer efficiency varies with animal movement and orientation
Solution Approach 1:
The system transitions from fixed to dynamic frequency tuning, where the resonant frequency is adjusted in real-time based on power transfer conditions. The microcontroller monitors coupling efficiency and modifies the operating frequency to maintain resonance between primary and secondary coils despite animal movement, thereby preventing energy loss without significantly increasing circuit complexity through the use of programmable frequency control.
Solution Approach 2:
The microcontroller serves multiple functions including data processing, power management, and frequency tuning. By integrating frequency adjustment capabilities into the existing control architecture, the system achieves adaptive resonance tuning without adding separate dedicated circuitry, thus minimizing the increase in device complexity while maintaining power transfer efficiency under varying conditions.
4Use of energy by moving object
If battery size is increased to provide sufficient power for high-quality data acquisition, then power capacity increases, but device size and weight increase
Solution Approach 1:
The patent introduces an external primary coil system as an intermediary power source that wirelessly transfers energy to the implantable device. This eliminates the need for large internal batteries, as the device receives power continuously from the external source through resonant coupling. The intermediary wireless power transfer mechanism provides sufficient power for high-quality data acquisition while keeping the implantable device small and lightweight.
Solution Approach 2:
The external primary coil system performs preliminary power preparation by generating and transmitting electromagnetic energy before it reaches the implantable device. This preliminary action of energy generation and wireless transmission allows the implantable device to operate with minimal internal power storage, as power is supplied in advance through the wireless link, thereby reducing device weight while maintaining adequate power capacity.
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 continuous, efficient power transfer to telemetric devices for extended periods, reducing the need for battery replacements and minimizing tissue damage risks, while allowing for flexible animal movement and orientation.
Implementation Method 1
a coil defining a coil axis; a tank capacitor electrically coupled to the coil and wherein the coil and the tank capacitor define a resonant frequency
Implementation Method 2
a rectifier coupled to the coil so as to receive and rectify an electrical voltage induced in the coil
Implementation Method 3
a ferrite rod having a rod axis and situated to be at least partially proximate to the coil
Implementation Method 4
a switching capacitor electrically coupled to the tank capacitor; and a microcontroller electrically coupled to the switching capacitor so as to tune or detune the resonant frequency established by the coil, the tank capacitor, and the switching capacitor
Data Source
AI summary
Disclosed herein are embodiments of novel WPT systems, devices, and methods of using the same. Also disclosed herein are methods for controlling the power delivered from a stationary source (e.g., a primary coil) to a moving telemetric device (e.g., a secondary coil) via magnetic resonance coupling. The systems, device, and methods described herein can be used to tune and/or detune resonant frequency between a primary coil and a telemetric device so as to prevent device malfunction and/or tissue damage for the small animals associated with the telemetric device.