Inductive Transmitter Coil Temperature Sensing for Safe Tissue Charging
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Solution Overview
Problem
Existing methods for inductively transferring electrical energy to a patient's body fail to optimize energy transfer without damaging tissue, as they do not accurately account for the warming of the temperature sensor by the transmitter coil's magnetic fields, leading to measurement errors and limited operating times.
Innovation Solution
Incorporating a temperature sensor that accounts for the warming caused by the transmitter coil's magnetic fields, either by using a fixed value or determining it based on temperature progression after the coil is stopped, to correct the measured temperature and optimize energy transfer within safe tissue temperature limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transmitter coil operates continuously to maximize energy transfer, then productivity is improved, but the temperature of the tissue and temperature sensor increases causing measurement errors and safety concerns
Solution Approach 1:
The transmitter coil is operated in periodic cycles rather than continuously. The control device switches the coil between active and inactive states, allowing the tissue and temperature sensor to cool down between cycles. This prevents excessive temperature buildup while maintaining effective energy transfer over time, directly resolving the contradiction between productivity and temperature control.
Solution Approach 2:
Temperature measurements are taken during the inactive phase before the next energy transfer cycle begins. This preliminary measurement ensures accurate baseline temperature data is captured before the transmitter coil is activated, preventing measurement errors that would occur if the sensor were heated during active operation.
2Measurement precision
If the temperature sensor is placed close to the measurement surface for accurate temperature detection, then measurement precision is improved, but the sensor is warmed by the magnetic fields resulting in measurement errors
Solution Approach 1:
The temperature sensor is positioned close to the measurement surface for optimal detection, but the system operates in periodic cycles where the transmitter coil is inactive during measurement phases. This timing separation allows the sensor to remain close to the surface for precision while avoiding warming from magnetic fields during the inactive measurement windows.
Solution Approach 2:
Temperature measurements are performed during the inactive phase before the transmitter coil activates. This preliminary measurement approach captures accurate temperature data before magnetic field warming occurs, eliminating measurement errors while maintaining optimal sensor placement for precision.
3Power
If the magnetic field strength is increased to enhance energy transfer, then power is improved, but the warming of the temperature sensor increases causing larger measurement errors
Solution Approach 1:
The system alternates between high-power energy transfer phases and measurement phases. During high-power phases, the transmitter coil operates at maximum field strength for optimal energy transfer. During inactive phases, measurements are taken when the magnetic field is minimal, ensuring sensor accuracy is not compromised by field-induced warming.
Solution Approach 2:
Temperature measurements are taken during inactive phases before the high-power transmitter coil activation. This preliminary measurement ensures that temperature data is captured before the strong magnetic fields cause sensor warming, maintaining measurement precision while allowing high power operation during energy transfer cycles.
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 approach allows for longer operating times, stronger magnetic fields, and more efficient energy transfer to the receiver coil, ensuring safe and effective charging of electrical energy stores in the patient's body.
Implementation Method 1
a transmitter coil (18) disposed in a transmitter unit (12) outside the body (1) for inductively transferring electrical energy to a receiver unit (14) disposed in a patient's body (1)
Implementation Method 2
the tissue of the patient between the receiver unit and the transmitter unit is warmed, in particular as a result of thermal losses in the transmitter unit and in the receiver unit
Implementation Method 3
the magnetic fields produced by the transmitter coil also warm the temperature sensor or its leads, which results in a measurement error
Data Source
AI summary
The invention relates to a transmitter unit (12) comprising a housing (20), a transmitter coil (18) arranged in the housing (20) for inductively transferring electrical energy to a receiver unit (14) which is provided with a receiver coil (16) and is arranged in the tissue (2) of the body (1) of a patient when the housing (20) having a contact surface (22) is placed on the body (1), and comprising a control device (30) for controlling the operation of the transmitter coil (18). According to the invention, a temperature sensor (26) is provided in the transmitter unit for determining a heating of the tissue (2) of the body (1) caused by the inductive transfer of electrical energy to the receiver unit (14). The invention also relates to methods for determining the temperature (TKorr) of the tissue (2) of a body (1) on a surface (38), by which electrical energy is inductively transmitted for supplying an electrical consumer arranged in the tissue (2) of the body (1), and to a method for inductively transferring electrical energy.