Wireless Power Transfer Coil Alignment via Bottom Part Detection

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Solution Overview

Problem

Existing wireless power transfer systems face challenges in efficiently supplying electric power to vehicles due to restrictions on distance and misalignment between the electric power supplying coil and the receiving coil, leading to significant energy loss, particularly when the vehicle type varies, requiring precise alignment for efficient power transfer.

Innovation Solution

A wireless power transfer system that includes a bottom part detection sensor, such as a laser or eddy current type distance sensor, to detect the vehicle's bottom part and extract coil position information, ensuring accurate alignment and efficient power transfer by outputting time-series detection signals and using contour matching or constant signal detection methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless power transfer is performed over a distance or with misalignment between coils, then ease of operation is improved, but energy loss increases significantly

Engineering Contradiction:
Improveease of power supply operationVSAvoidenergy loss in power transfer
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The system performs preliminary detection of the vehicle's bottom part position using a laser distance sensor before power transfer begins. This preliminary action allows the system to pre-align the coils and optimize their positions, ensuring that when power transfer starts, the alignment is already optimized to minimize energy loss while maintaining ease of operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the position of the vehicle's bottom part during the power transfer process using the laser distance sensor. Based on this feedback, the system adjusts the coil positions or orientations in real-time to maintain optimal alignment, thereby reducing energy loss while allowing flexible operation.

Inventive Principle:
Principle #23Feedback

2Device complexity

If the position of the electric power receiving coil is standardized for all vehicle types, then device complexity is reduced, but measurement precision deteriorates due to varying vehicle bottom part shapes

Engineering Contradiction:
Improvecomplexity of coil positioning systemVSAvoidprecision of coil position detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

Instead of using a single standardized coil position for all vehicles, the system detects the specific local geometry of each vehicle's bottom part and determines the optimal coil position tailored to that local configuration. The laser distance sensor measures distances to multiple points on the vehicle bottom, and the system calculates the precise position where the receiving coil should be placed for that specific vehicle, thereby maintaining high measurement precision without excessive complexity.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple detection sensors are installed to accurately detect vehicle bottom part position, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveprecision of vehicle position detectionVSAvoidcomplexity of detection sensor system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection process is segmented into multiple measurement points around the vehicle's bottom part. The laser distance sensor takes measurements at several discrete locations, and the system processes these segmented measurements to reconstruct the overall bottom part geometry and determine the optimal coil position. This segmentation approach achieves high measurement precision while keeping the sensor system relatively simple.

Inventive Principle:
Principle #1Segmentation

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

The system effectively specifies the position of the electric power receiving coil relative to the vehicle, improving power transfer efficiency by aligning the coils correctly, regardless of vehicle type, thereby reducing energy loss and enhancing the feasibility of wireless power supply.

Implementation Method 1

the bottom part detection sensor is a laser type distance sensor that is configured to output a bottom part detection signal corresponding to a separation distance between the portion which enters the detection range and the detection unit

Methodology Applied
Scientific EffectLaser time of flight measurement: Time of Flight

Implementation Method 2

electric power is fed in a wireless manner from the electric power supplying coil to the electric power receiving coil via a magnetic field formed in a space between the electric power supplying coil and the electric power receiving coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3157115B1Non-contact power feeding system
Publication Date: 2019.10.16 IHI CORP
  • EP3157115B1 patent drawingFigure 1
  • EP3157115B1 patent drawingFigure 2
  • EP3157115B1 patent drawingFigure 3

AI summary

A wireless power transfer system includes: a station that a vehicle is capable of entering and leaving; and a bottom part detection sensor having a detection unit capable of detecting an object that enters a detection range, provided at the station, and that outputs a bottom part detection signal corresponding to a portion, which enters the detection range, of a bottom part of the vehicle. The wireless power transfer system executes: a detection signal output step in which the bottom part detection sensor outputs a time-series bottom part detection signal when the vehicle moves in the station at a predetermined speed that is a prescribed speed; and a coil position information extraction step of extracting, from the time-series bottom part detection signal, coil position information that is information about a position of an electric power receiving coil in the vehicle.