Harmonic Impedance Sensing in Wireless Power Matching Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The efficiency of the class EF2 inverter in wireless power transmission is deteriorated due to varying load impedance caused by changes in distance between the wireless power transmitting device and the receiving terminal, leading to decreased charging efficiency.
Innovation Solution
A wireless power transmitting device that includes an impedance matching circuit and a method to sense load impedance by transferring a signal corresponding to harmonic frequencies through an LC resonance circuit, allowing for impedance adjustment to maintain optimal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the distance between the wireless power transmitting device and the receiving terminal varies, then the load impedance changes, but the charging efficiency deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the impedance sensing circuit continuously monitors the load impedance changes caused by distance variations, and the controller adjusts the impedance matching circuit parameters in real-time to maintain optimal charging efficiency despite the varying distance conditions
Solution Approach 2:
The patent employs dynamic impedance adjustment by making the impedance matching circuit parameters variable rather than fixed. The controller dynamically changes the matching circuit configuration based on real-time impedance sensing, allowing the system to adapt to different distance conditions and maintain high charging efficiency
2Adaptability or versatility
If the load impedance varies with distance, then the system becomes more adaptable to different positions, but the inverter efficiency decreases
Solution Approach 1:
The impedance sensing circuit provides continuous feedback on load impedance variations, enabling the controller to detect when impedance deviates from optimal values and trigger adjustments to the impedance matching circuit to restore efficient operation
Solution Approach 2:
The patent changes the electrical parameters of the impedance matching circuit (such as capacitance or inductance values) in response to detected impedance variations. This parameter adjustment allows the system to maintain resonance conditions and optimal power transfer efficiency across different operating distances
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 solution effectively prevents the deterioration of charging efficiency by sensing and adjusting impedance based on load changes, ensuring consistent performance across varying distances.
Implementation Method 1
an LC resonance circuit connected in parallel between the transistor and the matching circuit and transferring a signal corresponding to a harmonic frequency
Implementation Method 2
The inverter is a device that converts direct current (DC) power into alternating current (AC) power
Data Source
AI summary
A wireless power transmitting device includes: a transistor configured to output a signal corresponding to a set operating frequency, based on an input signal and a driving voltage; a matching circuit connected with the transistor; a transmission coil connected with the matching circuit; an LC resonance circuit connected in parallel between the transistor and the matching circuit and configured to transfer a signal corresponding to at least one harmonic frequency of the operating frequency; and an impedance sensing circuit connected with the LC resonance circuit and configured to sense a load impedance of the wireless power transmitting device based on the signal corresponding to the at least one harmonic frequency transferred through the LC resonance circuit. The matching circuit is configured to provide impedance matching with the sensed load impedance by adjusting an impedance of the matching circuit or an impedance of the transmission coil.