Wireless Energy Transmission Foreign Object Detection

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Solution Overview

Problem

Existing wireless energy transmission systems face disruptions and reliability issues due to foreign objects interfering with the electromagnetic field, causing heating and energy diversion, which complicates efficient energy transfer to consumers.

Innovation Solution

An iterative frequency sweep method is employed to detect local maxima of actual quality at resonant frequencies, allowing for precise identification of foreign objects and optimizing energy transmission by adjusting resonant frequency points, thereby improving detection accuracy and transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a comprehensive frequency sweep is performed to detect foreign objects, then detection accuracy is improved, but transmission time increases

Engineering Contradiction:
Improveforeign object detection accuracyVSAvoidtransmission time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial action by performing frequency sweeps only in specific scenarios (when quality factor changes indicate foreign object presence) rather than continuously across the entire frequency range. This reduces unnecessary time consumption while maintaining detection accuracy when needed.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The frequency sweep is segmented into targeted ranges based on quality factor changes. Instead of sweeping the entire frequency spectrum continuously, the system divides the detection into discrete intervals and performs sweeps only when quality factor variations suggest foreign object presence, reducing overall transmission time.

Inventive Principle:
Principle #1Segmentation

2Reliability

If foreign object detection is continuously performed, then reliability is improved, but energy consumption increases

Engineering Contradiction:
Improveenergy transmission reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system performs foreign object detection periodically based on quality factor changes rather than continuously. Quality factor monitoring serves as a trigger mechanism that initiates frequency sweeps only when necessary, maintaining reliability while significantly reducing energy consumption compared to continuous detection.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses its own quality factor measurements to self-determine when foreign object detection is necessary. The quality factor acts as an internal indicator that automatically triggers detection only when anomalies are detected, eliminating the need for continuous external monitoring and reducing energy consumption.

Inventive Principle:
Principle #25Self-service

3Productivity

If resonant frequency is adjusted to avoid foreign objects, then energy transmission efficiency is improved, but detection complexity increases

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoiddetection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses quality factor measurements as feedback to automatically adjust resonant frequency when foreign objects are detected. The quality factor serves as a real-time indicator that feeds back to the control system, which then adjusts the frequency to maintain optimal transmission efficiency without requiring complex detection algorithms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the resonant frequency parameter in response to quality factor variations indicating foreign object presence. By adjusting this key parameter, the system maintains energy transmission efficiency while avoiding the need for complex multi-parameter detection and adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 faster and more reliable foreign object detection, reducing the need for comprehensive frequency sweeps and enhancing overall energy transmission processes by pinpointing local maxima of actual quality, thus ensuring uninterrupted and efficient energy transfer.

Implementation Method 1

If an electrically conductive foreign object comes within the range of the electromagnetic field of the coils, eddy currents can form that heat up the foreign object.

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

If the foreign object can be magnetized, it can also be heated up by hysteresis or remagnetization losses.

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Implementation Method 3

the wireless energy transmission takes place by means of an electromagnetic field from a primary-side energy supply device

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3673562B1Method for wireless energy transmission from an energy transmission device to a consumer and wireless transmission device for carrying out the method
Publication Date: 2023.04.05 ROBERT BOSCH GMBH
  • EP3673562B1 patent drawingFigure 1
  • EP3673562B1 patent drawingFigure 2
  • EP3673562B1 patent drawingFigure 3

AI summary

The invention proposes a method for wireless, in particular inductive, energy transmission from an energy transmission device (14) to a consumer (18), wherein in at least one method step, the energy transmission from the energy transmission device (14) to the consumer (18) is interrupted in connection with a foreign object detection. According to the invention, an iterative process for a frequency sweep in order to detect a local maximum of an actual quality (Qact,A(fres,A), Qact,n+1(fres)) of the wireless energy transmission, which is characteristic of a resonant frequency (fres,A, fres), is provided in at least one method step (50).