Variable Diameter Power Feeding Coil Impedance Matching
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Solution Overview
Problem
Current wireless power feeding systems based on electromagnetic resonance require complex circuitry for impedance matching, leading to increased circuit scale, cost, and power loss, especially when adjusting for changes in impedance and distance between power transmitting and receiving coils.
Innovation Solution
A power feeding apparatus and method that includes an impedance detector, controller, and variable matching circuit in the power transmitter, allowing for dynamic impedance adjustment by changing the diameter of the power feeding coil based on detected impedance, with control information transmitted wirelessly to the power receiving apparatus for independent impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electromagnetic induction method is used for wireless power feeding, then power transmission efficiency is improved, but power feeding distance is limited and alignment is required
Solution Approach 1:
The patent changes the fundamental parameter of the power transmission method from electromagnetic induction to electromagnetic resonance. This parameter change enables power transmission over longer distances while maintaining acceptable efficiency levels, resolving the contradiction between transmission efficiency and feeding distance.
2Length of stationary object
If electromagnetic resonance method is used for wireless power feeding, then power feeding distance is extended and alignment is not required, but circuit complexity increases due to dynamic impedance control requirements
Solution Approach 1:
The patent applies impedance matching circuits on both the power feeding side and power receiving side. The receiving side creates a copy of the impedance control function, allowing the transmitting side to operate with simplified circuitry while maintaining overall system impedance matching through the cooperative action of both sides.
3Reliability
If impedance detector and variable matching circuit are added to both power feeding and receiving devices, then impedance matching is improved, but circuit scale increases and cost increases
Solution Approach 1:
The patent distributes the impedance matching function to both transmitting and receiving ends. Each end has simplified impedance control circuits that work cooperatively, avoiding the need for complex impedance detection and matching circuits at both ends while achieving reliable impedance matching through the combined action of both sides.
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 reduces circuit complexity and power loss while maintaining efficient impedance matching, preventing increases in circuit scale and cost, and ensuring optimal power transfer across varying distances and impedance changes.
Implementation Method 1
The electromagnetic induction method is known to supply power wirelessly
Implementation Method 2
the electromagnetic induction method is known to supply power wirelessly
Data Source
AI summary
A power feeding apparatus, power receiving apparatus, wireless power feeding system, and method for wireless transfer of power are provided. The power feeding apparatus includes an impedance detector, a controller, a power transmitter, a variable matching circuit, and a signal transmitter. The controller is configured to provide first control information and second control information based on an impedance detected by the impedance detector. The power feeding apparatus' variable matching circuit is configured to change a variable diameter of a power feeding coil according to the first control information. The power receiving apparatus includes a power receiver, a signal receiver, and a variable matching circuit. The power receiving apparatus' variable matching circuit is configured to change a variable diameter of a power feeding coil according to the second control information provided by the power feeding apparatus.