Contactless Power Alignment Detection for Resonant Charging

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Solution Overview

Problem

In contactless power supply systems using magnetic field resonance coupling, the alternating current magnetic field is often generated continuously, leading to power wastage and potential interference with electronic devices. Additionally, misalignment between the transmission-side and reception-side resonance circuits can decrease power transmission efficiency.

Innovation Solution

A contactless power supply system that accurately detects the relative positional relationship between the transmission-side and reception-side resonance circuits using an alternating current magnetic field generation circuit and a magnetic field detector, allowing for timely generation of the alternating current magnetic field during vehicle passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the alternating current magnetic field is generated continuously for contactless power transmission, then the power transmission capability is improved, but the power wastage increases and interference with electronic devices occurs

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidpower wastage
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The system generates the alternating current magnetic field periodically based on the detected position of the mobile body, rather than continuously. The power supply device activates the transmission-side resonance circuit only when the mobile body is within the power transmission region, and deactivates it when the mobile body moves away, thus achieving periodic operation that reduces energy waste while maintaining effective power transmission capability

Inventive Principle:
Principle #19Periodic action

2Loss of energy

If the alternating current magnetic field is generated only when needed, then the power wastage is reduced, but the timing accuracy for power transmission may be compromised

Engineering Contradiction:
Improvepower wastageVSAvoidtiming accuracy
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system performs preliminary detection of the mobile body's position using the magnetic field detector before initiating power transmission. By continuously monitoring the position in advance and predicting when the mobile body will enter the power transmission region, the system can activate the alternating current magnetic field at the optimal moment, ensuring both energy efficiency and timing accuracy

Inventive Principle:
Principle #10Preliminary action

3Loss of time

If wireless communication is used to detect the approach of the mobile body, then the power transmission timing can be controlled, but the communication may be hindered by obstacles

Engineering Contradiction:
Improvepower transmission timing controlVSAvoidcommunication reliability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The system uses the magnetic field detector as an intermediary detection mechanism that does not rely on line-of-sight wireless communication. The magnetic field can penetrate obstacles that block radio waves, allowing the system to detect the mobile body's position and approach reliably even when obstacles are present, thereby maintaining both timing control and communication reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If the transmission-side and reception-side resonance circuits are misaligned, then the system simplicity is maintained, but the power transmission efficiency decreases

Engineering Contradiction:
Improvesystem simplicityVSAvoidpower transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system employs feedback through the magnetic field detector to continuously monitor the relative positional relationship between the transmission-side and reception-side resonance circuits. Based on this feedback information, the power supply device adjusts its operation to maintain optimal alignment, thereby improving power transmission efficiency without significantly increasing system complexity

Inventive Principle:
Principle #23Feedback

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 efficient and timely power transmission by ensuring proper alignment of the resonance circuits and minimizing power wastage, while also reducing potential interference with electronic devices.

Implementation Method 1

contactless electric power transmission of magnetic field resonance coupling between a ground-side device and a mobile body using a transmission method such as magnetic field coupling (electromagnetic induction)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnetic field detector provided in the mobile body... detects a relative positional relationship between a transmission-side resonance circuit and a reception-side resonance circuit

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 3

contactless electric power transmission of magnetic field resonance coupling using a transmission-side resonance circuit and a reception-side resonance circuit having the same resonance frequency

Methodology Applied
Scientific EffectMagnetic field resonance coupling: Resonance

Data Source

PatentEP4105066B1Contactless power supply system, position estimation method, mobile body, and power supply device
Publication Date: 2025.06.11 TOYOTA JIDOSHA KK
  • EP4105066B1 patent drawingFigure 1
  • EP4105066B1 patent drawingFigure 2~3
  • EP4105066B1 patent drawingFigure 4~5

AI summary

Provided is a contactless power supply system (1) including a transmission-side resonance circuit (43) configured to transmit electric power, a reception-side resonance circuit (51) configured to receive the electric power from the transmission-side resonance circuit (43), an alternating current magnetic field generation circuit (6) configured to generate an alternating current magnetic field for detecting a relative positional relationship between the transmission-side resonance circuit (43) and the reception-side resonance circuit (51), and a magnetic field detector (7) configured to detect the alternating current magnetic field. The contactless power supply system (1) performs contactless electric power transmission of magnetic field resonance coupling between a ground-side device (2) and a mobile body (3). A frequency of the position detecting alternating current magnetic field is different from a resonance frequency of each of the transmission-side resonance circuit (43) and the reception-side resonance circuit (51).