Wireless Charging Pad LF Signal Alignment
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Solution Overview
Problem
Conventional alignment methods for magnetic resonance wireless power transfer systems are prone to user intervention errors and coil misalignment, leading to reduced efficiency and stability in power transfer due to the need for manual alignment of primary and secondary coils.
Innovation Solution
A position measurement method using low-frequency (LF) signals is employed to accurately align the primary coil of the charging station with the secondary coil of the electric vehicle by transmitting LF signals, adjusting transmission strength based on reception strengths, and determining alignment through defined regions and intersection points, ensuring precise coil alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment methods (rear camera or bump-based) are used to align coils, then the system can be operated with simple hardware, but the alignment accuracy deteriorates leading to coil misalignment and reduced power transfer efficiency
Solution Approach 1:
The patent replaces mechanical alignment methods (manual positioning, bump-based alignment) with an electromagnetic field-based measurement system. Low frequency signals are transmitted through multiple LF spots on the charging pad, and the vehicle measures reception strengths to calculate its position relative to the charging pad, enabling automatic high-precision alignment without mechanical intervention.
Solution Approach 2:
The patent introduces low frequency signals as an intermediary medium between the charging pad and the vehicle for position measurement. These LF signals serve as a mediator that carries position information from the charging pad to the vehicle, enabling indirect measurement of alignment status without direct mechanical contact or visual observation.
2Ease of operation
If manual alignment intervention is required, then the system structure can be simplified, but the ease of operation deteriorates due to user intervention errors and inconvenience
Solution Approach 1:
The patent implements self-service alignment where the vehicle autonomously determines its position relative to the charging pad using LF signal measurements and automatically calculates alignment status. The system performs self-correction by providing guidance information to the driver, eliminating the need for manual alignment intervention and reducing user errors.
Solution Approach 2:
The patent establishes a feedback loop where the vehicle continuously measures LF signal reception strengths, calculates its position, determines alignment status with the charging pad, and provides feedback information to the driver. This closed-loop system enables real-time monitoring and correction of alignment status, improving both ease of operation and reliability.
3Device complexity
If simple alignment methods are used, then the device complexity is reduced, but the measurement precision deteriorates leading to substantial deviation in coil alignment
Solution Approach 1:
The patent divides the charging pad into multiple LF spots (at least four spots positioned at vertices or along edges of the charging coil). Each LF spot independently transmits low frequency signals, and the vehicle measures reception strengths from multiple spots to calculate its position through triangulation or multilateration, achieving high measurement precision through segmented measurement points.
Solution Approach 2:
The patent transitions from two-dimensional visual alignment (camera-based) or mechanical alignment to three-dimensional spatial positioning using LF signal propagation. By measuring signal reception strengths from multiple LF spots at known positions, the system calculates the vehicle's position in space, adding a dimensional aspect to the alignment measurement process.
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 method enhances the accuracy of coil alignment, thereby maximizing wireless charging efficiency and improving the stability and reliability of the power transfer system.
Implementation Method 1
transmitting low frequency (LF) signals having a same strength through a plurality of LF spots of the charging pad
Data Source
AI summary
A position measurement method for position alignment with a vehicle, performed by a charging pad, may comprise performing synchronization with a vehicle entering a vicinity of the charging pad, transmitting low frequency (LF) signals having a same strength through a plurality of LF spots of the charging pad, receiving information on reception strengths of the LF signals from the vehicle, adjusting a transmission strength for the plurality of LF spots according to the information on reception strengths received from the vehicle, and transmitting the LF signals according to the adjusted transmission strength.