Contactless Power Transfer Frequency Correction for Thermal Resonance Drift
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Solution Overview
Problem
Existing contactless electric power transmission systems experience output decreases and efficiency losses due to variations in the eigenvalue (frequency) of the resonance circuit caused by temperature changes in the electric power reception side, particularly from temperature fluctuations in coils and capacitors.
Innovation Solution
A contactless electric power transmission system that includes a control device with temperature acquisition and correction mechanisms to adjust the request frequency based on the temperatures of the coil, capacitor, and magnetic member, correcting self-inductance, resistance, and mutual inductance to maintain optimal resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the request frequency is fixed without temperature compensation, then the device complexity is reduced, but the power transmission efficiency decreases due to resonance circuit eigenvalue variation
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the request frequency based on temperature measurements. Temperature sensors monitor the coil and capacitor temperatures, and the control device modifies the request frequency parameter to compensate for eigenvalue shifts in the resonance circuit, thereby maintaining optimal power transmission efficiency without requiring complex real-time frequency sweeping
Solution Approach 2:
The patent implements feedback control by measuring temperatures of the coil and capacitor, calculating the eigenvalue variation based on these temperature readings, and adjusting the request frequency accordingly. This closed-loop feedback mechanism maintains resonance conditions despite temperature changes, improving power transmission efficiency without excessive system complexity
2Reliability
If temperature compensation is implemented, then the power transmission stability is improved, but the device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The patent changes the operational parameter (request frequency) based on temperature measurements to maintain stable power transmission. By adjusting the request frequency to compensate for eigenvalue shifts, the system achieves reliable operation across varying temperature conditions without requiring redundant hardware or complex control algorithms
Solution Approach 2:
The patent replaces complex mechanical or iterative frequency adjustment mechanisms with a calculated approach. Instead of using complex frequency sweeping or multiple adjustable components, the system calculates the required frequency adjustment based on temperature-eigenvalue relationships, simplifying the overall system structure while maintaining stability
3Loss of energy
If the request frequency is adjusted based on temperature, then the resonance circuit efficiency is maintained, but the control precision requirements increase
Solution Approach 1:
The patent uses feedback from temperature sensors to adjust the request frequency. By continuously monitoring temperature and calculating the corresponding eigenvalue shift, the system maintains resonance efficiency without requiring extremely high measurement precision, as the control algorithm can accommodate reasonable measurement tolerances
Solution Approach 2:
The patent applies partial correction by adjusting the request frequency based on temperature measurements within a certain range. The control device calculates eigenvalue variation and applies frequency compensation that is sufficient to maintain efficiency without requiring ultra-precise temperature measurement, accepting that minor deviations are tolerable while still achieving the primary goal of efficiency maintenance
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
Prevents output decreases and efficiency losses by dynamically adjusting the request frequency in response to temperature variations, ensuring stable and efficient power transmission.
Implementation Method 1
an electric power reception portion having a coil that receives AC electric power transmitted in a contactless manner from an electric power transmission side coil
Implementation Method 2
an eigenvalue (frequency) of a resonance circuit formed of a coil, a capacitor, and the like of an electric power reception side
Data Source
AI summary
A contactless electric power transmission system includes an electric power reception device and a control device. The electric power reception device receives AC electric power transmitted in a contactless manner from an electric power transmission device. The control device includes: a coil temperature detection portion that acquires temperatures of a secondary side coil, a magnetic member, and a secondary side capacitor of the electric power reception device; a magnetic member temperature detection portion; and a capacitor temperature detection portion. The control device includes a request frequency correction portion that corrects a request frequency of electric power transmission by the electric power transmission device based on the temperatures of the secondary side coil, the magnetic member, and the secondary side capacitor.