Wireless Power Transfer Auxiliary Resonator Alignment
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Solution Overview
Problem
Conventional wireless power transfer methods face inefficiencies and reduced power transfer distances due to improper alignment and size disparities between power transmission and receiving coils, especially when a shielding member is present, and require additional adjusting circuits for resonance frequency matching.
Innovation Solution
Incorporating a power-transmission auxiliary device with an auxiliary coil and resonant capacitance to form a power receiving space between the power transmission coil and the auxiliary coil, allowing the power receiving coil to be disposed within this space, which enables efficient power transfer without the need for adjusting circuits and maintains power transfer efficiency across varying distances and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If magnetic field resonance type power transfer is used to extend transmission distance, then power transmission distance is improved, but power transfer efficiency significantly reduces when shielding member is interposed or coil alignment is improper
Solution Approach 1:
The patent introduces a resonance frequency adjusting circuit as an intermediary component between the power receiving coil and the power transmission coil. This circuit actively adjusts the resonance frequency of the power receiving coil to match that of the power transmission coil, thereby maintaining efficient power transfer even when shielding members are present or coil alignment is improper. The adjusting circuit acts as a mediator that compensates for environmental interference and misalignment issues.
Solution Approach 2:
The patent dynamically changes the resonance frequency parameter of the power receiving coil by adjusting its capacitance value. The resonance frequency adjusting circuit modifies the electrical parameters (capacitance) of the power receiving coil to optimize resonance conditions, enabling efficient power transfer across varying distances and orientations without significant efficiency loss.
2Loss of energy
If resonance frequency adjusting circuit is added to power receiver, then power transfer efficiency is maintained under various conditions, but device complexity increases
Solution Approach 1:
The resonance frequency adjusting circuit is configured to automatically detect and adjust the resonance frequency of the power receiving coil without requiring external control or complex processing. The circuit self-regulates by monitoring the power transfer conditions and autonomously adjusting its capacitance value to maintain optimal resonance, thereby reducing the need for additional control systems and minimizing overall device complexity.
3Volume of moving object
If power receiving coil size is reduced for portable equipment, then portability is improved, but power transfer efficiency and transmission distance are reduced
Solution Approach 1:
The patent compensates for the reduced size of the power receiving coil by dynamically adjusting its resonance frequency parameter. The resonance frequency adjusting circuit modifies the electrical characteristics of the smaller coil to optimize its resonant conditions, enabling it to achieve efficient power transfer and extended transmission distance despite its compact dimensions. This parameter adjustment allows small coils to perform as effectively as larger coils would under optimal resonance conditions.
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 configuration enhances power transfer efficiency and distance by flattening the distance dependency of power transfer, allowing reliable power transfer even with improper coil alignment and smaller receiving coils, while eliminating the need for resonance frequency adjustment in the receiver.
Implementation Method 1
the electric or magnetic field resonance-type power transfer methods recently has been attracting attention, because of a ability of a short-distance transfer (up to 2 m). Among them, in the electric field resonance type method, when placing the hand or the like in a transfer path, a dielectric loss is caused, because the human body, which is a dielectric, absorbs energy as heat. In contrast, in the magnetic field resonance type method, the human body hardly absorbs energy and a dielectric loss thus can be avoided.
Implementation Method 2
The loop coil 3a is a dielectric element that is excited by an electric signal supplied from the high-frequency power driver 5 and transfers the electric signal to the power transmission coil 4a by electromagnetic induction. The power transmission coil 4a generates a magnetic field based on the electric signal that has been output from the loop coil 3a.
Data Source
AI summary
A wireless power transfer device including: a power transmitter 1 including a power transmission resonator composed of a power transmission coil and a resonant capacitance; and a power receiver including a power receiving resonator composed of a power receiving coil and a resonant capacitance. The wireless power transfer device further includes a power-transmission auxiliary device including an auxiliary resonator composed of an auxiliary coil and a resonant capacitance. The power-transmission auxiliary device and the power transmitter are configured to be disposed so as to face each other, forming a power receiving space for disposing the power receiving coil between the power transmission coil and the auxiliary coil. An efficient power transfer can be performed without providing an adjusting circuit in the power receiver even when the power receiving coil is not appropriately disposed with respect to the power transmission coil.