Wireless Power Receiver Timing for Foreign Object Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wireless power transfer systems face challenges in accurately detecting foreign objects within the operating range, which can lead to reduced efficiency and potential heat generation, as current methods may not effectively differentiate between the presence of a foreign object and normal operation conditions.

Innovation Solution

A power reception apparatus is configured with a first measurement unit to assess received power during a limited power transmission period and a second measurement unit to detect foreign objects based on the relationship between transmitted and received power, utilizing a control unit to manage timing such that these periods do not overlap, allowing for precise foreign object detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If foreign object detection is performed continuously during power transmission, then detection accuracy is improved, but power transmission efficiency deteriorates due to overlapping measurement periods

Engineering Contradiction:

Improveforeign object detection accuracyVSAvoidpower transmission efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent divides foreign object detection into two distinct segments: first foreign object detection performed during limited power transmission periods, and second foreign object detection performed during non-limited power transmission periods. This segmentation allows each detection type to operate in optimized time windows, preventing interference between measurement activities and maintaining both detection accuracy and power transmission efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic foreign object detection by alternating between limited power transmission periods (for first FOD) and non-limited power transmission periods (for second FOD). This periodic action ensures that detection measurements are taken at regular intervals without continuously interrupting power transmission, thereby maintaining system productivity while achieving reliable foreign object detection.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If power transmission is limited for measurement purposes, then measurement accuracy is improved, but power transmission time increases

Engineering Contradiction:

Improvereceived power measurement accuracyVSAvoidpower transmission time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs first foreign object detection during limited power transmission periods before transitioning to non-limited power transmission. This preliminary action establishes baseline measurement data under controlled conditions, allowing subsequent second FOD to be performed more efficiently without requiring repeated limited transmission periods, thus reducing overall time loss.

Inventive Principle:

Principle #10Preliminary action

3Difficulty of detecting and measuring

If foreign object detection is performed using existing methods, then detection capability is provided, but ability to differentiate foreign objects from normal operation conditions is insufficient

Engineering Contradiction:

Improveforeign object detection capabilityVSAvoiddifferentiation accuracy between foreign objects and normal operation

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent segments foreign object detection into two distinct methods: first FOD during limited power transmission and second FOD during non-limited power transmission. By comparing results from both segments, the system can differentiate between foreign objects (which would be detected in both periods) and normal operation variations (which would only appear in one period), thereby improving measurement precision and reducing false positives.

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

This approach enables accurate detection of foreign objects, ensuring efficient power transfer and preventing heat generation by distinguishing between normal operation and foreign object presence, thus enhancing the reliability of wireless power transfer systems.

Implementation Method 1

a power reception unit configured to wirelessly receive power from a power transmission apparatus

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS12142943B2Power reception apparatus, control method, and computer-readable storage medium

Publication Date: 2024.11.12 CANON KK

AI summary

A power reception apparatus wirelessly receives power from a power transmission apparatus, measures a value corresponding to received power in a first period in which the power transmission apparatus limits power transmission, measures, in a second period, a value corresponding to received power used to detect an object different from the power transmission apparatus and the power reception apparatus based on a relationship between a value corresponding to transmitted power in the power transmission apparatus and a value corresponding to the received power in the power reception apparatus, controls a timing of the second period such that the first period and the second period do not overlap.