Wireless Charging Coil Alignment Using LF Signal TDM
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Solution Overview
Problem
Conventional methods for aligning primary and secondary coils in wireless charging systems for electric vehicles are prone to user intervention errors, leading to inefficiencies and reduced stability due to misalignment, which affects the power transfer efficiency and reliability in magnetic resonance wireless power transfer systems.
Innovation Solution
A position alignment method using low-frequency (LF) signals, where a vehicle assembly identifies and communicates with a target ground assembly through a supply equipment communication controller, performing authentication and alignment using unique LF signals distinguished by a time division multiplexing scheme to prevent interference and ensure accurate coil alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment methods (rear camera or bump-based) are used, then the system is simpler to implement, but the alignment precision deteriorates leading to coil misalignment and reduced power transfer efficiency
Solution Approach 1:
The patent introduces LF signals as an intermediary medium to facilitate precise alignment between the EV and charging station. The LF signals act as a communication bridge that enables the EV to identify and align with the correct charging pad without direct mechanical intervention or complex camera systems, thereby achieving high alignment precision while maintaining system simplicity
Solution Approach 2:
The patent replaces mechanical alignment methods (such as bump-based physical contact or camera-based visual alignment) with electromagnetic field-based LF signal communication. This substitution eliminates the need for complex mechanical systems while achieving superior alignment precision through signal-based identification and positioning
2Reliability
If user intervention is required for coil alignment, then the system complexity is reduced, but the reliability deteriorates due to user errors and inconvenience
Solution Approach 1:
The patent enables the EV and charging station to perform alignment automatically through LF signal communication without requiring user intervention. The EV autonomously identifies the correct charging pad using LF signals and aligns itself, eliminating user errors and improving reliability while maintaining high automation level
Solution Approach 2:
The patent implements a feedback mechanism where the charging station transmits LF signals that the EV detects and uses to determine its position relative to the charging pad. This continuous feedback loop enables automatic adjustment and precise alignment, ensuring high reliability through automated control
3Productivity
If LF signals from multiple GAs are transmitted simultaneously, then the communication efficiency is improved, but the measurement precision deteriorates due to signal interference and collision
Solution Approach 1:
The patent implements periodic transmission of LF signals by different GAs in a time-division manner. Each GA transmits its LF signal in alternating time slots, preventing signal collision while maintaining efficient communication. This periodic action ensures that the EV can accurately detect and identify the correct charging pad without interference from other GAs
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 enhances the precision and reliability of coil alignment, improving power transfer efficiency and stability by minimizing interference and ensuring correct position alignment data acquisition, even in environments with multiple vehicles and charging stations.
Implementation Method 1
The wireless charging of the battery for driving the electric motor of the EV may be performed by coupling a primary coil of a charging station with a secondary coil of the EV in a magnetic resonance manner
Implementation Method 2
coupling a primary coil of a charging station with a secondary coil of the EV in a magnetic resonance manner
Data Source
AI summary
A position alignment method for wireless charging performed by a VA for position alignment with a target GA is provided. The method includes identifying states of a plurality of GAs via wireless communication with an SECC that operates the plurality of GAs and receiving, from the SECC, information regarding one or more available GAs of the plurality of GAs. A target GA based is selected on the information regarding available GAs and a wireless communication association with the target GA is performed. A procedure for position alignment approval and a procedure for authentication is executed by a request to the SECC and in response to determining that the authentication is successful, position alignment with the target GA using LF signals is performed, wherein LF signals assigned to each GA are distinguished from LF signals assigned to other GAs in a TDM scheme.