Wireless Power Transfer Coil Alignment via Induced Voltage Measurement
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Solution Overview
Problem
Conventional alignment methods for wireless power transfer systems in electric vehicles require user intervention, leading to coil misalignment and reduced efficiency, stability, and reliability due to sensitivity to alignment errors.
Innovation Solution
An alignment method and apparatus that moves a primary or secondary coil through a series of measurement points to calculate and adjust its position based on induced physical quantities, such as voltage and power transfer efficiency, without using auxiliary coils, to achieve precise magnetic field alignment between the coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment methods using rear camera or user intervention are used, then the alignment process is simple to implement, but the alignment precision deteriorates leading to coil misalignment and reduced power transfer efficiency
Solution Approach 1:
The system performs self-alignment by automatically measuring physical quantities at multiple measurement points and calculating the optimal position without requiring user intervention or auxiliary alignment tools. The primary coil or secondary coil autonomously determines its position based on the measured physical quantities (voltage, current, power transfer efficiency) and adjusts accordingly.
Solution Approach 2:
The patent replaces mechanical alignment methods (such as visual alignment using rear cameras or physical guidance structures) with an electromagnetic field-based measurement system. The system uses the magnetic field coupling between coils to measure physical quantities and calculate position, substituting mechanical alignment procedures with electromagnetic sensing and computational analysis.
2Reliability
If conventional alignment methods requiring user intervention are used, then the device structure remains simple, but the reliability deteriorates due to large deviation in alignment and poor system stability
Solution Approach 1:
The system implements feedback by measuring physical quantities at multiple measurement points, comparing the measured values, and automatically adjusting the coil position based on the calculated optimal position. The measurement results feed back into the position calculation algorithm, enabling iterative refinement of alignment accuracy and ensuring reliable power transfer.
3Productivity
If precise alignment is achieved through multiple measurement points and calculations, then power transfer efficiency improves, but the alignment process time increases
Solution Approach 1:
The system performs preliminary measurements at multiple predetermined measurement points before final alignment is established. By pre-measuring physical quantities at various positions and storing the data, the system can quickly determine the optimal position without requiring extensive real-time measurements during the actual alignment process, thus reducing overall alignment time while maintaining high precision.
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 improves power transfer efficiency, enhances system stability, and reduces maintenance costs by eliminating the need for user intervention and auxiliary means, ensuring precise alignment of wireless power transfer coils in electric vehicles.
Implementation Method 1
it may be necessary to couple a primary coil of a charging station with a secondary coil of the EV using magnetic resonance
Implementation Method 2
measuring physical quantities induced in the primary coil by a power or a magnetic field of a secondary coil magnetically coupled with the primary coil
Implementation Method 3
measuring physical quantities induced in the primary coil by a power or a magnetic field of a secondary coil magnetically coupled with the primary coil
Data Source
AI summary
Disclosed are alignment methods and apparatuses for power transmission/reception coils in an electric vehicle wireless power transfer system. An alignment method may comprise moving a primary coil such that a reference center point of the primary coil sequentially passes through a plurality of measurement points located on the primary coil or located outside the primary coil; measuring physical quantities induced in the primary coil by a power or a magnetic field of a secondary coil magnetically coupled with the primary coil at the reference center point and the plurality of measurement points; and calculating a relative position of the primary coil with respect to the secondary coil based on the measured physical quantities.