Wireless Power Transfer System with Self-Tuning Oscillator
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Solution Overview
Problem
Existing wireless power transfer systems for biomedical implants face inefficiencies due to variations in distance and alignment between the external battery and implant, leading to fluctuations in power delivery and reduced efficiency, often requiring complex additional circuits or extra components that increase cost and complexity.
Innovation Solution
A wireless power transfer system with a self-tuning oscillator and adaptive loop control that maintains stable power delivery across varying distances and resistive loads by automatically adjusting the resonant frequency and quality factor, eliminating the need for voltage limiters or alignment magnets, and minimizing energy loss through efficient transistor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between external battery and implant varies, then power delivery stability deteriorates, but adding complex additional circuits or extra components increases device complexity and cost
Solution Approach 1:
The system employs self-tuning oscillators on both transmitter and receiver sides that automatically adjust their operating frequencies to maintain resonant coupling conditions. This self-adjusting mechanism eliminates the need for external control circuits or additional components to compensate for distance variations, achieving stable power delivery through the inherent adaptive behavior of the resonant circuits
Solution Approach 2:
The patent utilizes variable operating frequency as a control parameter to adapt to changing coupling conditions. By allowing the oscillator frequency to vary dynamically based on load and distance conditions, the system maintains optimal power transfer efficiency without requiring complex control mechanisms
2Loss of energy
If the load current changes significantly in implants alternating between monitoring and stimulation, then power transfer efficiency deteriorates, but using complex control circuits increases device complexity
Solution Approach 1:
The system implements implicit feedback through the resonant coupling mechanism itself. The coupled resonators naturally adjust their operating point based on load conditions, with the oscillator automatically tuning to maintain maximum power transfer. This feedback mechanism is inherent in the resonant system rather than requiring separate control circuits
Solution Approach 2:
The patent employs dynamic frequency adjustment where the oscillator frequency varies continuously to track optimal coupling conditions. This dynamic adaptation allows the system to maintain high efficiency across varying load conditions by continuously optimizing the operating parameters rather than requiring discrete control interventions
3Reliability
If axes misalignment occurs between external battery and implant, then power delivery stability deteriorates, but adding alignment magnets or voltage limiters increases device complexity and cost
Solution Approach 1:
The system compensates for misalignment by dynamically adjusting the operating frequency to match the shifted resonant conditions caused by axis misalignment. The coupled resonators' frequency response naturally adapts to the changed geometric configuration, maintaining stable power transfer without requiring mechanical alignment aids
4Reliability
If additional data transfer links or complex digital control blocks are added to compensate for variations, then power delivery stability improves, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent replaces complex digital control systems and data transfer links with an analog resonant coupling mechanism that inherently provides stability. The coupled resonators' physical coupling properties naturally compensate for variations, eliminating the need for digital sensing, processing, and control infrastructure
Solution Approach 2:
The system achieves stability through self-tuning oscillators that automatically adapt to changing conditions without external control. This self-adjusting behavior eliminates the need for additional control blocks, sensors, or data transfer mechanisms that would increase manufacturing complexity and cost
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 system achieves high power transfer efficiency and stable voltage delivery to biomedical implants with reduced complexity and cost, maintaining efficiency over a range of distances and load variations without additional data transfer links or complex digital control blocks.
Implementation Method 1
a coupled resonator link configured to deliver power from a transmitter tank circuit to a receiver tank circuit
Implementation Method 2
the free-running oscillator automatically tunes to oscillate at a frequency that does not experience a phase shift due to the impedance of the transmit side of the coupled resonator link
Data Source
AI summary
Wireless power transfer systems in accordance with embodiments of the invention are disclosed. In one embodiment, a wireless power transfer system includes a power transmitter driven by an oscillator, a power receiver including a resistive load, and a coupled resonator link configured to deliver power from a transmitter tank circuit to a receiver tank circuit, wherein the free-running oscillator automatically tunes to oscillate at a frequency that does not experience a phase shift due to the impedance of the transmit side of the coupled resonator link, wherein the power transmitter provides regulated voltage across a range of distances between the transmitter tank circuit and the receiver tank circuit, and wherein the power transmitter regulates voltage across a range of resistive loads of the power receiver.