Wireless Power Resonator Position Detection Using Dual-Frequency Inductance

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Solution Overview

Problem

Current wireless power transfer systems face challenges in performing high-precision positional adjustment between power transmission and reception coils, especially when the load changes, leading to inefficiencies and increased costs due to the need for complex configurations and additional components.

Innovation Solution

A power transmission apparatus that oscillates alternating current power at two frequencies, measuring inductance values at each frequency to calculate a coupling coefficient, allowing for precise positional adjustment of resonators without the need for additional switches or control circuits, using a capacitor to create open and short-circuit states in the power reception apparatus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex configurations and additional components (switches, control circuits) are used to achieve high-precision positional adjustment, then measurement precision is improved, but device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvepositional adjustment precisionVSAvoidconfiguration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the position detection function from complex control circuits and switches, implementing it through a simplified method that uses the existing resonator system's electrical characteristics (impedance, coupling coefficient) to determine relative position, thereby eliminating the need for additional switches and control circuits while maintaining high-precision positional adjustment

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The resonator system performs self-diagnosis of its own position by monitoring changes in its electrical characteristics (impedance, coupling coefficient) that naturally occur with position changes, eliminating the need for external complex detection circuits and enabling high-precision positional adjustment through the system's inherent properties

Inventive Principle:
Principle #25Self-service

2Productivity

If complex configurations and additional components are used to maintain efficiency with changing loads, then productivity is improved, but device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidconfiguration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic load adaptation by continuously monitoring the resonator's electrical characteristics (impedance, coupling coefficient) and adjusting the power transmission parameters accordingly, enabling the system to maintain high power transfer efficiency under varying load conditions without requiring complex additional control circuits

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the resonator's electrical characteristics (impedance changes, coupling coefficient variations) to automatically adjust power transmission parameters, maintaining optimal efficiency with changing loads through a simple feedback mechanism that avoids complex configurations

Inventive Principle:
Principle #23Feedback

3Measurement precision

If additional switches and control circuits are added to improve measurement precision, then measurement precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveposition detection precisionVSAvoidmanufacturing simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the need for additional switches and control circuits by extracting position detection capability from complex hardware and implementing it through measurements of the resonator's inherent electrical characteristics, thereby improving measurement precision while simplifying manufacturing

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The resonator system serves multiple functions simultaneously: it performs both power transmission and position detection using the same hardware components, eliminating the need for separate detection circuits and making the system easier to manufacture while maintaining high-precision position detection

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

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

Enables high-precision positional adjustment with a simple configuration and reduced costs, maintaining efficiency even with changing loads, by calculating the coupling coefficient based on inductance values measured at different frequencies.

Implementation Method 1

an oscillation circuit that oscillates alternating current power at a first frequency (f1) which is lower than a resonant frequency (fr) of the second resonator and at a second frequency (f2) which is higher than the resonant frequency (fr)

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

a first resonator including a first coil; an oscillation circuit that oscillates alternating current power at a first frequency (f1) which is lower than a resonant frequency (fr) of the second resonator

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

a measuring circuit that measures an inductance value Lin(f1) of the first resonator when the oscillation circuit oscillates alternating current power at the first frequency (f1) and an inductance value Lin(f2) of the first resonator when the oscillation circuit oscillates alternating current power at the second frequency (f2)

Methodology Applied
Scientific EffectMagnetic Field: Magnetic Field

Data Source

PatentEP3355437B1Power transmission apparatus and power reception apparatus for wireless power transfer and wireless power transfer system
Publication Date: 2021.02.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3355437B1 patent drawingFigure 1~2
  • EP3355437B1 patent drawingFigure 3~4
  • EP3355437B1 patent drawingFigure 5

AI summary

A power transmission apparatus oscillates alternating current power at a first frequency (f1) which is lower than a resonant frequency (fr) of the second resonator and at a second frequency (f2) which is higher than the resonant frequency (fr). The power transmission apparatus measures an inductance value Lin (f1) and an inductance value Lin (f2). The inductance value Lin (f1) is measured when the oscillation circuit oscillates alternating current power at the first frequency (f1), and the inductance value Lin (f2) is measured when the oscillation circuit oscillates alternating current power at the second frequency (f2). The power transmission apparatus calculates a coupling coefficient k by using an expression represented by k2 = 1-Lin(f2)/Lin(fl), to detect relative position of the second resonator to the first resonator on the basis of the coupling coefficient k.