Wireless Power Transfer Coil Positioning for Coupling Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless power transfer systems, changes in the coupling coefficient between coils due to variations in coil shape and distance lead to inefficiencies in power transfer, requiring adjustments in voltage on the transmitting side or conversion ratios on the receiving side to maintain efficiency.
Innovation Solution
A power transmitting apparatus with a mutual coupling adjusting unit and control unit that adjusts the relative position between the power transmitting and receiving inductors to maintain a desired coupling coefficient, thereby controlling the voltage conversion ratio and ensuring efficient power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the coupling coefficient between coils varies due to changes in coil shape or distance, then the power transfer efficiency changes, but the voltage conversion ratio control range must be increased to maintain efficient power transfer
Solution Approach 1:
The control unit continuously monitors the coupling coefficient between the transmitting and receiving coils and dynamically adjusts the voltage conversion ratio of the DC-DC converter in response to detected changes, maintaining optimal power transfer efficiency without requiring an excessively wide control range
Solution Approach 2:
The system employs dynamic adjustment of the voltage conversion ratio based on real-time coupling conditions, allowing the converter to adapt its operation mode (buck, boost, or buck-boost) according to the instantaneous coupling coefficient, thereby reducing the need for a predetermined wide control range
2Loss of energy
If the distance between coils is minimized to increase transfer efficiency, then the coupling coefficient increases, but the system loses adaptability to positional variations
Solution Approach 1:
The system dynamically adjusts the voltage conversion ratio in response to changing coupling conditions caused by positional variations, allowing the coils to be positioned at optimal distances for different operating conditions while maintaining high efficiency through real-time control adjustments
Solution Approach 2:
The control unit changes the operating parameters (voltage conversion ratio) of the DC-DC converter based on detected coupling coefficient variations, enabling the system to maintain high power transfer efficiency across a range of distances and positional configurations
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 maintains transmission power and efficiency while reducing the control range of voltage conversion ratios, ensuring consistent power delivery even with changes in positional relationships between the power transmitting and receiving apparatuses.
Implementation Method 1
a power transmitting inductor transferring AC power to a power receiving apparatus through magnetic coupling with a power receiving inductor in the power receiving apparatus
Implementation Method 2
When power is transferred by resonating the resistance and conductance of the coils, a higher maximum value of transfer efficiency between the coils is obtained as a product of the coupling coefficient k between the coils and the Q value of the coils becomes higher
Data Source
AI summary
A power transmitting apparatus including a power supply to generate AC power; a power transmitting inductor to transfer the AC power to a power receiving apparatus through magnetic coupling with a power receiving inductor in the power receiving apparatus; a mutual coupling adjusting unit to adjust a relative position between the power transmitting inductor and the power receiving inductor; and a control unit to control the mutual coupling adjusting unit based on a mutual coupling coefficient between the power transmitting inductor and the power receiving inductor. The control unit controls the mutual coupling adjusting unit so that the mutual coupling coefficient falls within a predetermined range and an upper limit of the predetermined range is a value less than a maximum of the mutual coupling coefficient between the power transmitting inductor and the power receiving inductor.