Self-regulating Transcutaneous Energy Transfer via Dynamic Resonance Detuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless power interfaces for implantable medical devices face challenges in efficiently transferring power without overheating, as they are sensitive to coil alignment and require additional hardware like RF telemetry links to manage thermal issues, leading to increased charging times or complexity.
Innovation Solution
An implantable device with a secondary coil that dynamically adjusts its resonant frequency or is temporarily short-circuited to regulate the power received from an external charger unit, preventing excessive power absorption and overheating without the need for additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the coils are positioned in close proximity for efficient power transfer, then power transfer efficiency is improved, but the device becomes sensitive to alignment and overheating occurs
Solution Approach 1:
The patent applies dynamics by making the resonant frequency of the secondary coil adjustable rather than fixed. The control loop dynamically tunes the resonant frequency to track the primary coil's operating frequency, optimizing power transfer efficiency while preventing excessive power absorption that causes overheating. This dynamic adjustment allows the system to adapt to varying alignment conditions during charging.
Solution Approach 2:
The patent implements feedback through a control loop that monitors the power transfer conditions and adjusts the resonant frequency of the secondary coil accordingly. The control loop detects deviations from optimal resonance and automatically tunes the frequency to maintain efficient power transfer while preventing overheating, creating a self-regulating system.
2Temperature
If additional hardware like RF telemetry links is added to manage thermal issues, then temperature control is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the secondary coil to automatically regulate its own power absorption through resonant frequency tuning. The control loop within the implantable device independently adjusts the resonant frequency to match the primary coil's operating frequency, optimizing power transfer without requiring external temperature monitoring or control hardware. This self-regulating mechanism eliminates the need for additional thermal management components.
3Loss of energy
If the resonant frequency is dynamically adjusted to regulate power received, then power transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the resonant frequency parameter of the secondary coil to optimize power transfer. The control loop modifies the resonant frequency in response to changing conditions, allowing the system to maintain high efficiency without requiring complex control mechanisms. This parameter adjustment is achieved through standard circuit components that tune the LC resonant circuit.
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 ensures safe and efficient power transfer, preventing overheating while maintaining reasonable charging times without the added complexity or cost of RF telemetry links.
Implementation Method 1
producing an oscillating magnetic field proximate the external charger unit... producing an alternating current at the driving frequency in a secondary coil
Implementation Method 2
a secondary coil for receiving the oscillating magnetic field and producing an alternating current at the driving frequency
Data Source
AI summary
A rechargeable battery system and method are disclosed, in which an implantable medical device (IMD) regulates its transfer of energy from a separate charger unit. For recharging, a charger unit is brought into proximity to the implanted device. An oscillating current is generated in a primary coil, located in the charger. By inductive coupling through an oscillating magnetic field, an alternating current is generated in a secondary coil, which is implanted in or near the implanted device. The alternating current then passes through a half-wave or full-wave rectifier to form a one-sided current, then passes through a regulator to form an essentially direct current, which is in turn directed to the rechargeable battery in the implanted device. The secondary coil has a controllable damped resonant frequency, which can be dynamically tuned away from the driving frequency of the primary coil by a variable resistor and/or by varying a duty cycle of a rapidly switched electrical element. If a control loop in the implant senses that more power is being received at the second coil than is actually being used to recharge the battery, the control loop temporarily changes the variable resistance. When this happens, the resonant frequency of the secondary coil is detuned slightly away from the driving frequency, so that less of the incoming power is absorbed by the secondary coil. Alternatively, the secondary coil may be temporarily short-circuited. With less or no excess power entering the circuitry of the implant, the problem of overheating is mitigated.