Wireless Power Transmitter Position Estimation

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Solution Overview

Problem

Current wireless power transfer systems face inefficiencies due to misalignment between transmitter and receiver coils, leading to longer charging times, power wastage, and other user inconveniences, as perfect alignment cannot be guaranteed in practical applications.

Innovation Solution

A method for estimating the relative position of a wireless power receiver coil with respect to a transmitter coil is developed, using a position estimator that compares test parameter values to calibration data for various misalignments, incorporating power loss, resonance frequency, and coupling measures to determine optimal alignment and improve power transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the receiver coil is placed very close to the transmitter coil to achieve high coupling factor, then power transfer efficiency is improved, but the alignment requirement becomes extremely strict and difficult to maintain in practical applications

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidalignment tolerance
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The patent implements dynamic alignment adjustment by enabling the receiver coil to move relative to the transmitter coil based on detected coupling conditions. The system continuously monitors power transfer efficiency and adjusts the receiver position in real-time to maintain optimal coupling, transforming a static alignment problem into a dynamic adaptation process that resolves the contradiction between high efficiency requirements and practical alignment difficulty

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms by detecting the coupling factor between transmitter and receiver coils and using this information to control the alignment process. The system measures power transfer efficiency and feeds this data back to adjust the receiver position, creating a closed-loop control system that automatically maintains optimal coupling without requiring manual precision alignment

Inventive Principle:
Principle #23Feedback

2Measurement precision

If multiple test parameters are measured to improve position estimation accuracy, then alignment precision is improved, but the system complexity and measurement time increase

Engineering Contradiction:
Improveposition estimation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by selectively measuring only the most critical test parameters needed for position estimation rather than comprehensively measuring all possible parameters. The system identifies and measures key parameters such as coupling factor and impedance changes that provide sufficient position information, avoiding the complexity of measuring every conceivable parameter while maintaining adequate estimation accuracy

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent implements preliminary action by performing rough position estimation first using simplified measurements, then refining the estimate only when necessary with additional measurements. The system initially uses basic coupling detection to establish approximate position, then applies more complex measurement sequences only when the initial estimate indicates potential alignment issues, reducing overall system complexity while maintaining precision when needed

Inventive Principle:
Principle #10Preliminary action

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 enhances the accuracy of position estimation, allowing for improved power transfer efficiency, user feedback, and adaptability, reducing charging times and power wastage, while maintaining compatibility with existing standards like Qi Specifications.

Implementation Method 1

power is inductively transferred from a transmitter coil in a power transmitter device to a receiver coil in the individual devices

Methodology Applied
Scientific EffectMagnetic induction: Electromagnetic Induction

Implementation Method 2

a position estimator is arranged to estimate a position of the power receiver relative to the power transmitter

Methodology Applied
Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Data Source

PatentEP3818621B1Power transmitter and method of operation therefor
Publication Date: 2022.03.30 KONINKLIJKE PHILIPS NV
  • EP3818621B1 patent drawingFigure 1
  • EP3818621B1 patent drawingFigure 2
  • EP3818621B1 patent drawingFigure 3

AI summary

A power transmitter (101) for wirelessly providing power to a power receiver (105) comprises a retriever (209) retrieving calibration data comprising a set of calibration parameters for each of a plurality of spatial positions of a calibration receiver relative to a calibration transmitter. A test generator (207) generates a test drive signal for a transmitter coil (103) to generate an electromagnetic test signal, and a test processor (213) determines a set of test parameters in response to the test drive signal. A position estimator (207) estimates a position of the power receiver relative to the power transmitter in response to a comparison of the test parameters to the calibration parameters for the plurality of spatial positions. The parameters include a power loss measure, a resonance frequency measure, and a coupling measure. The approach and specific parameters provide a substantially improved position estimation.