Wireless Power Feeder Selective Resonance Frequency Control
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in selectively transmitting power to multiple receivers without complex frequency control and with a simple feeder configuration, especially when receivers have different resonance frequencies and varying coil sizes.
Innovation Solution
A wireless power transmission system using a power feed coil and control circuit that supplies AC power based on magnetic field resonance, allowing selective power transmission to plural receivers with different resonance frequencies, and utilizing a power receive coil and capacitor in each receiver, where the power receive coil is smaller than half the size of the power feed coil to minimize mutual inductance changes and simplify drive frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power receive coil is made larger to improve power reception efficiency, then the magnetic coupling with the power feed coil increases, but the mutual inductance changes significantly with distance variations, causing resonance frequency instability
Solution Approach 1:
The patent applies parameter changes by optimizing the size ratio between the power receive coil and power feed coil. Specifically, the power receive coil is designed to be smaller than 1/4 of the winding region or smaller than 1/2 of the winding diameter of the power feed coil. This parameter optimization balances magnetic coupling strength for efficient power reception while minimizing mutual inductance variations with distance, thereby maintaining resonance frequency stability.
2Adaptability or versatility
If multiple receivers with different resonance frequencies are supported, then the system versatility increases, but the feeder configuration and frequency control become more complex
Solution Approach 1:
The patent implements universality by designing a single power feed coil configuration that can serve multiple receivers with different resonance frequencies. The key is making the power receive coil sufficiently smaller than the power feed coil, which minimizes mutual inductance changes and allows the feeder to maintain a simple, universal configuration while supporting diverse receivers through frequency sweeping rather than complex adaptive configuration changes.
Solution Approach 2:
The patent employs periodic action through frequency sweeping, where the AC power frequency is periodically varied to match different receiver resonance frequencies. This periodic frequency modulation allows the simple feeder configuration to selectively power different receivers without requiring complex real-time configuration adjustments, thereby maintaining feeder simplicity while achieving multi-receiver compatibility.
3Length of stationary object
If the power receive coil size is increased to extend transmission distance, then the magnetic field coverage improves, but the mutual inductance variation with distance increases, complicating frequency control
Solution Approach 1:
The patent resolves this contradiction through parameter optimization of the coil size ratio. By designing the power receive coil to be smaller than 1/4 of the winding region or smaller than 1/2 of the winding diameter of the power feed coil, the system achieves extended transmission distance through sufficient magnetic field coverage while simultaneously minimizing mutual inductance variations with distance. This parameter optimization ensures that frequency control remains simple and does not require complex compensation mechanisms.
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
Enables efficient, non-contact power transmission to multiple receivers with reduced complexity in frequency control and the ability to use the same product for receivers with varying resonance frequencies, while maintaining a simple feeder configuration and allowing longer transmission distances compared to conventional methods.
Implementation Method 1
a power feeding source excitation element (excitation coil) coupled to the power feeding source resonance element by electromagnetic induction
Implementation Method 2
a power receive resonance circuit including a power receive coil and a power receive capacitor, and the wireless power feeder comprises a power feed coil and a control circuit supplying AC power to the power feed coil. The control circuit in the wireless power feeder performs power feeding selectively to the plural wireless power receivers by changing frequency of the AC power on the basis of a magnetic field resonance effect between the power feed coil and the power receive coil.
Data Source
AI summary
A wireless power transmission system according to an embodiment of the present invention is a wireless power transmission system performing non-contact power transmission from a wireless power feeder selectively to a plurality of wireless power receivers, and each of the plurality of wireless power receivers comprises a power receive resonance circuit including a power receive coil and a power receive capacitor, and the wireless power feeder comprises a power feed coil and a control circuit supplying AC power to the power feed coil. The control circuit in the wireless power feeder performs power supply selectively to the plurality of wireless power receivers by changing frequency of the AC power on the basis of a magnetic field resonance effect between the power feed coil and the power receive coil.