Low-Frequency Magnetic Field Alignment for Wireless Power Transfer
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Solution Overview
Problem
Conventional methods for aligning primary and secondary coils in magnetic resonance wireless power transfer systems are prone to user intervention errors, leading to inefficiencies and reduced stability due to slight misalignments, making precise alignment challenging, especially at close distances.
Innovation Solution
The use of low-frequency (LF) magnetic field signals and strategically arranged LF antennas and sensors on both the vehicle assembly and ground assembly to accurately measure and align the position of the coils, ensuring optimal power transfer efficiency by calculating the distance between the transmission and reception pads based on detected magnetic field values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional alignment techniques (rear camera or bump-based movable charging pad) are used, then alignment can be achieved with simple implementation, but user intervention is required and alignment precision deteriorates leading to excessive system performance deterioration
Solution Approach 1:
The patent replaces mechanical alignment methods (rear camera visual alignment or bump-based physical adjustment) with a magnetic field-based detection system. LF transmitting devices and receiving devices detect magnetic field values to calculate precise distance and orientation between coils, eliminating the need for mechanical intervention while achieving sub-centimeter alignment precision.
Solution Approach 2:
The patent introduces magnetic field values as an intermediary medium between the transmitting and receiving coils. By measuring magnetic field strength at multiple positions and calculating gradient values, the system obtains precise positional information without direct mechanical contact or visual intervention, resolving the contradiction between precision and complexity.
2Reliability
If magnetic resonance wireless power transfer is used, then power transfer efficiency can be high when coils are aligned, but the system becomes highly sensitive to coil misalignment causing stability deterioration
Solution Approach 1:
The patent implements a feedback mechanism where LF receiving devices continuously detect magnetic field values from transmitting devices, calculate distance and orientation, and provide this information back to the alignment system. This closed-loop feedback enables real-time correction of coil misalignment, maintaining high power transfer efficiency and system stability even when external disturbances occur.
Solution Approach 2:
The patent performs preliminary alignment using magnetic field detection before initiating wireless power transfer. By calculating gradient values of magnetic field strength at multiple positions and determining optimal coil orientation in advance, the system ensures precise alignment is achieved before the high-power magnetic resonance transfer begins, preventing stability issues during operation.
3Ease of operation
If coil alignment is performed manually by users, then implementation remains simple, but alignment accuracy deteriorates due to user intervention errors
Solution Approach 1:
The patent enables the alignment system to perform self-service by automatically detecting magnetic field values, calculating gradient values, determining optimal positions and orientations, and guiding the alignment process without user intervention. The system autonomously achieves precise coil alignment while maintaining ease of operation through automated guidance indicators.
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 enables precise alignment of coils even at close distances, enhancing the efficiency and stability of wireless charging by accurately measuring and aligning the magnetic fields, thus maximizing power transfer efficiency and reliability.
Implementation Method 1
transmitting at least one magnetic field using one or more transmitting devices disposed on the reception pad, the one or more transmitting devices operating with low frequency (LF)
Implementation Method 2
receiving at least one magnetic field related value from the GA, the at least one magnetic field being detected by one or more LF receiving devices disposed on the transmission pad of the GA
Implementation Method 3
calculating, by a controller, a distance between the transmission pad and the reception pad using the at least one magnetic field related value
Data Source
AI summary
A position alignment method, performed by a vehicle assembly (VA) including a reception pad receiving power transmitted from a transmission pad of a ground assembly (GA) is provided. The method includes transmitting a magnetic field using a transmitting device disposed on a reception pad, the transmitting device operating with low frequency (LF); receiving a magnetic field related value from the GA, the magnetic field being detected by an LF receiving device disposed on the transmission pad of the GA; and calculating, by a controller, a distance between the transmission pad and the reception pad using the magnetic field related value. A part of the transmitting device is disposed to arrange a magnetic field formed by the part of the transmitting device in a 0°, 90°, 180°, or 270° direction with respect to a magnetic field formed by a part of the LF receiving device.