Tire Relay Coil Wireless Power Transfer for Moving Vehicles

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Solution Overview

Problem

Existing dynamic wireless power transfer systems face challenges in maintaining high power transmission efficiency due to varying distances between power transmission and reception coils, especially when vehicles are in motion, and the need to account for changing distances.

Innovation Solution

A dynamic wireless power transfer system that uses relay coils embedded in vehicle tires to stabilize the distance between power transmission and reception coils, employing resonance frequencies centered on a prescribed frequency to enhance efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a battery is used as a power source in an electric vehicle, then the vehicle can operate independently of external power sources, but the battery weight increases and reduces overall vehicle efficiency

Engineering Contradiction:
Improveindependent operation capabilityVSAvoidbattery weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent combines the battery and wireless power receiver into a single integrated power supply unit. The battery serves dual purposes: providing independent operation capability when wireless power is unavailable, and assisting wireless power reception by providing resonant inductance. This merging eliminates the need for separate heavy battery systems while maintaining independent operation capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The battery is designed to perform multiple functions: (1) providing power for independent vehicle operation, (2) serving as a resonant inductor for wireless power reception, and (3) stabilizing the power supply during charging. This multi-functionality reduces the need for dedicated heavy components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of energy

If a battery is used to assist wireless power reception by providing resonant inductance, then power reception efficiency improves, but the battery must maintain precise resonance conditions which complicates control

Engineering Contradiction:
Improvepower reception efficiencyVSAvoidresonance control complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent incorporates a controller that continuously monitors the wireless power reception process and adjusts the battery's operation to maintain optimal resonance conditions. The controller receives feedback on power reception efficiency and dynamically controls the battery's inductance contribution, automatically compensating for variations in operating conditions without requiring complex manual adjustment.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If the battery operates in parallel with the wireless power receiver, then power supply stability improves, but current distribution control becomes more complex

Engineering Contradiction:
Improvepower supply stabilityVSAvoidcurrent distribution control
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The controller continuously monitors the power supply conditions and dynamically adjusts the battery's current output to maintain stable total power delivery. The feedback mechanism automatically balances the current distribution between the battery and wireless power receiver based on real-time operating conditions, eliminating the need for complex manual current sharing arrangements.

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

The system improves power transfer efficiency by stabilizing the distance and resonance frequencies, reducing losses, and leveling power transfer across varying vehicle positions and movements.

Implementation Method 1

a wireless power transmitter which transmits power wirelessly to the power receiver

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a battery and a power receiver that receives power wirelessly from the wireless power transmitter are connected in parallel

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4005851B1Power feeding system during traveling
Publication Date: 2026.05.06 DENSO CORP
  • EP4005851B1 patent drawingFigure 1
  • EP4005851B1 patent drawingFigure 2
  • EP4005851B1 patent drawingFigure 3A

AI summary

A dynamic wireless power transfer system (500) includes: a power transmission coil (40) that is provided in a road (105); a power transmission circuit (30) that supplies electric power to the power transmission coil; a power reception coil (240f, 240r) that is provided in a vehicle (202); a power reception circuit (230) that is connected to the power reception coil; and a relay circuit (70) that is provided in a tire of the vehicle, includes at least two relay coils that are connected in series, and transfers electric power from the power transmission coil to the power reception coil by one (71a1) relay coil of the two relay coils opposing the power transmission coil and the other (71a2) relay coil opposing the power reception coil. A resonance frequency of the relay circuit is a frequency that is within a fixed range that is centered on an applied frequency of an alternating-current voltage that is applied to the power transmission coil.