Low Frequency Coil 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 inefficient and require user intervention, leading to misalignment and reduced power transfer efficiency.

Innovation Solution

A method and apparatus using low-frequency signals to measure and align the position of the vehicle's secondary coil with the ground assembly's primary coil by comparing maximum and minimum magnetic flux densities, providing precise alignment through a received signal measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional alignment techniques (rear camera or movable charging pad) are used, then the alignment process can be performed, but user intervention is required and substantial deviation occurs leading to excessive system performance deterioration

Engineering Contradiction:

Improvealignment precisionVSAvoiduser intervention requirement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-alignment by automatically measuring magnetic flux density and calculating position deviation without user intervention. The ground assembly autonomously determines the vehicle's position and adjusts the charging pad movement accordingly, eliminating the need for manual alignment operations.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical alignment operations with an automated electromagnetic field-based measurement and control system. Low-frequency magnetic fields are used to detect vehicle position, and the system automatically processes this data to control charging pad movement, substituting human mechanical alignment with automated electromechanical control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional alignment techniques are used, then alignment can be attempted, but slight coil misalignment causes substantial deviation and excessive system performance deterioration

Engineering Contradiction:

Improvesystem stabilityVSAvoidalignment accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system continuously measures magnetic flux density and compares it against reference values to determine position deviation. This feedback mechanism allows the system to detect even slight misalignments and make real-time corrections by controlling charging pad movement, ensuring accurate coil alignment and maintaining high power transfer efficiency.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary position measurement using magnetic flux density detection before initiating the charging process. By measuring and calculating position deviation in advance, the system can pre-adjust the charging pad position to ensure optimal alignment before power transfer begins, preventing misalignment-related performance deterioration.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If magnetic resonance wireless power transfer is used, then power transfer efficiency is sensitive to coil alignment, but conventional alignment methods require user intervention and result in substantial deviation

Engineering Contradiction:

Improvepower transfer efficiencyVSAvoidalignment system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent introduces low-frequency magnetic field measurement as an intermediary mechanism between the vehicle and charging pad. This intermediary system provides precise position information that enables accurate alignment control, bridging the gap between the two components and ensuring optimal power transfer efficiency without requiring complex manual alignment procedures.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 accurate alignment of the coils, maximizing wireless charging efficiency and improving system stability and reliability by automating the alignment process.

Implementation Method 1

at least one low frequency (LF) transmitter; a communication module configured to receive a received signal measurement from a ground assembly (GA) that detects the first magnetic flux density and the second magnetic flux density

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

measuring, through at least one LF receiver of the GA, a first magnetic flux density for a magnetic field emitted from at least one LF transmitter of a vehicle assembly (VA)

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11552509B2Apparatus and method for measuring vehicle position based on low frequency signals

Publication Date: 2023.01.10 KIA CORPORATION

AI summary

A position alignment method performed by a ground assembly for wireless power transfer includes measuring, through at least one low frequency (“LF”) receiver of the ground assembly, a first magnetic flux density for a magnetic field emitted from at least one LF transmitter of a vehicle assembly; measuring, through the at least one LF receiver, a second magnetic flux density for a magnetic field emitted from the at least one LF transmitter; configuring a received signal measurement based on a comparison result of the first magnetic flux density and the second magnetic flux density; and providing the configured received signal measurement to a vehicle.