Wireless Power Coupling Coefficient Derivation Method
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Solution Overview
Problem
Existing electric-field-coupling-scheme wireless power transmission systems face challenges in optimizing coupling capacitance and coupling coefficient, leading to inefficiencies and labor-intensive design processes due to unknown parameter values and measurement errors.
Innovation Solution
A parameter derivation method that calculates the coupling coefficient using resonant and anti-resonant frequencies of the input impedance, allowing for the quantification of capacitances and optimizing electrode design for improved power transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If coupling capacitance and coupling coefficient are optimized to increase power transmission efficiency, then power transmission efficiency is improved, but design complexity increases due to unknown parameter values requiring repeated trial-and-error design
Solution Approach 1:
The patent transforms the design approach from trial-and-error physical electrode design to calculated parameter determination. By measuring resonant frequencies and using equations to calculate coupling capacitance and coupling coefficient values, the invention directly determines optimal parameters without repeated design iterations, thus improving power transmission efficiency while reducing design complexity
Solution Approach 2:
The patent replaces the mechanical trial-and-error design process with an electrical measurement and calculation system. Instead of physically adjusting electrode configurations repeatedly, the invention uses frequency measurement and mathematical equations to directly compute optimal coupling parameters, substituting physical iteration with computational determination
2Measurement precision
If coupling parameters are directly measured in practical operation state, then measurement accuracy is improved, but parasitic capacitances from measurement instruments cause measurement errors
Solution Approach 1:
The patent extracts the coupling parameters from the complex practical operation state by measuring only resonant frequencies, which can be obtained without direct coupling measurements. By measuring input impedance characteristics at resonant frequencies and using equations to calculate coupling capacitance and coupling coefficient, the invention avoids direct measurement that would introduce parasitic capacitance errors
Solution Approach 2:
The patent uses resonant frequency measurement as an intermediary method to indirectly determine coupling parameters. Instead of directly measuring coupling capacitance or coupling coefficient (which would require direct connection and introduce parasitic effects), the invention measures resonant frequencies of the system and uses these as intermediate values to calculate the desired parameters through mathematical relationships
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 method simplifies the design process by deriving accurate parameter values, reducing measurement errors, and enhancing power transmission efficiency in wireless power transmission systems.
Implementation Method 1
a power transmission device that applies an alternating current voltage, which has been stepped up by a step-up transformer, between a first electrode and a second electrode
Implementation Method 2
the wireless power transmission system transmitting power from the power transmission device to the power reception device via electric field coupling
Implementation Method 3
a power reception device that steps down with a step-down transformer a voltage induced in a third electrode that faces the first electrode with a gap therebetween
Implementation Method 4
using resonant frequencies ω1 and ω2 or anti-resonant frequencies ω00 and ω0 of an input impedance seen from a primary side of the step-up transformer measured in a state where the third electrode and the fourth electrode are open and using a resonant frequency ωr or an anti-resonant frequency ωa of the input impedance seen from the primary side of the step-up transformer measured in a state where the third electrode and the fourth electrode are short circuited
Data Source
AI summary
A method for determining parameters of a wireless power transmission system is disclosed where the wireless power transmission system transmits power from a power transmission device to a power reception device via electric field coupling. The parameters include a coupling coefficient ke of an electric field coupling unit that is formed of active electrodes and passive electrodes of the power transmission device and the power reception device.