Wireless Power Coil Switching for Distance-Dependent Transfer Efficiency
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Solution Overview
Problem
The efficiency of power transfer in wireless power feed systems using the resonance method is compromised when the resonant coils of the power feeding and receiving devices are not at an optimal distance, with efficiency dropping when they are either too far or too close.
Innovation Solution
The solution involves interchanging the positions of the electromagnetic coupling coil and resonant coil in the power feeding and receiving devices, with switches controlling the power transfer method between resonance and electromagnetic coupling based on the distance between the devices, ensuring high efficiency by switching to electromagnetic coupling when coils are close and maintaining resonance when at an optimal distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the resonant coil of the power feeding device and the resonant coil of the power receiving device are positioned at an optimal distance for resonance method, then power transfer efficiency is improved, but when the distance becomes too close or too far, power transfer efficiency deteriorates
Solution Approach 1:
The system dynamically switches between resonance method and electromagnetic coupling method based on the distance between power feeding device and power receiving device. When distance is optimal, resonance method is used; when distance deviates from optimal, electromagnetic coupling method is activated to maintain efficiency, making the system adaptable to varying distances.
Solution Approach 2:
The wireless power feed system incorporates both resonance method and electromagnetic coupling method capabilities, allowing it to perform multiple power transfer functions. This multi-functionality enables the system to maintain high efficiency across different distance conditions by selecting the appropriate method.
2Loss of energy
If only resonance method is used for wireless power feed, then power transfer efficiency is high at optimal distance, but the system cannot adapt when devices are too close or too far apart
Solution Approach 1:
The system employs dynamic method selection, switching between resonance and electromagnetic coupling based on real-time distance conditions. This dynamic adaptation maintains ease of operation across various distances while preserving high power transfer efficiency through appropriate method selection.
3Loss of energy
If electromagnetic coupling coil is positioned between resonant coils, then the system can maintain efficiency at close distances, but device structure becomes more complex
Solution Approach 1:
The power transfer function is segmented into two distinct methods: resonance method for optimal distances and electromagnetic coupling method for close distances. By dividing the power transfer mechanism into separate functional components (resonant coils for resonance, electromagnetic coupling coils for coupling), the system manages complexity through functional segmentation while maintaining efficiency.
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 approach maintains high power transfer efficiency across varying distances between the power feeding and receiving devices, ensuring efficient energy transfer regardless of the relative positioning.
Implementation Method 1
The resonant coil of the power feeding device and the resonant coil of the power receiving device are adjusted to resonate (LC resonance) at the same frequency
Implementation Method 2
Feeding power from a power source in the power feeding device to the resonant coil and feeding power from the resonant coil in the power receiving device to a load are conducted by the electromagnetic coupling coils
Data Source
AI summary
A wireless power feed system with high transfer efficiency of electric power is disclosed. The wireless power feed system includes a power feeding device and a power receiving device, wherein the power feeding device includes a first electromagnetic coupling coil that is connected to an AC power source via a directional coupler; a first resonant coil; a switch connected to the opposite ends of the first resonant coil; a control circuit which conducts switching on/off of the switch based on a parameter of an amplitude of a reflective wave detected by the directional coupler; and an analog-digital converter provided between the first electromagnetic coupling coil and the control circuit; and the power receiving device includes a second resonant coil; and a second electromagnetic coupling coil, and wherein the first electromagnetic coupling coil is provided between the first resonant coil and the second resonant coil.