Wireless Power Transfer Foreign Object Detection
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Solution Overview
Problem
Loosely coupled wireless power systems face inefficiencies and safety risks due to non-compliant objects within or near the charging region, leading to unaccounted power losses and potential harm.
Innovation Solution
A system that measures energy transfer and reception over specific periods using a processor to compare energy provided and received, determining if non-compliant objects are absorbing power by calculating the integral of current and voltage, and adjusting power transmission accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless power transmission is performed without detecting non-compliant objects, then power transfer efficiency is maintained, but safety risks and energy loss increase
Solution Approach 1:
The system performs foreign object detection before initiating full power transmission. The processor measures the impedance of the charging region and compares it against reference values to identify non-compliant objects in advance, allowing the system to adjust or prevent power transmission to avoid energy loss and safety hazards.
Solution Approach 2:
The system continuously monitors power transmission parameters and compares transmitted power with received power feedback from the charging region. When discrepancies indicate the presence of non-compliant objects, the system adjusts transmission power levels dynamically to prevent energy waste and potential harm.
2Reliability
If foreign object detection is performed before initial charging, then safety is improved, but detection accuracy decreases due to fine foreign objects
Solution Approach 1:
The system performs an initial impedance measurement before charging to detect foreign objects. This preliminary detection uses a different measurement approach (impedance-based) that is sensitive to fine foreign objects that may not be detected by traditional methods, thereby improving overall detection accuracy while maintaining safety.
Solution Approach 2:
The system changes detection parameters by using impedance measurement at different frequencies or power levels. By adjusting the measurement parameters based on the charging state, the system can detect both large and fine foreign objects with high accuracy across different operating conditions.
3Reliability
If power limitation is applied when foreign objects are detected, then safety is improved, but power transmission efficiency decreases
Solution Approach 1:
Instead of completely limiting power when foreign objects are detected, the system applies partial power limitation based on the severity and type of foreign object detected. The processor calculates appropriate power levels that maintain safety while minimizing impact on charging efficiency, allowing partial power transmission in certain conditions.
Solution Approach 2:
The system dynamically adjusts transmission power parameters based on foreign object detection results. Rather than applying a fixed power limit, the processor modifies power transmission parameters (voltage, current, frequency) to optimize both safety and efficiency for different foreign object scenarios.
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
Accurately detects non-compliant objects and adjusts power transfer to prevent energy loss and ensure safety, improving the reliability and safety of wireless charging systems.
Implementation Method 1
an antenna configured to provide wireless power to a chargeable device
Implementation Method 2
determine whether an object other than the chargeable device is absorbing power provided via the antenna based at least in part on comparing the first amount of energy and the second amount of energy
Data Source
Figure 1~3
Figure 4A
Figure 4B
AI summary
An apparatus and method for lost power detection are described. In one implementation, an apparatus for wirelessly transferring power includes an antenna configured to provide wireless power to a chargeable device sufficient to charge or power the chargeable device positioned within a charging region of the antenna. The apparatus further includes a receiver configured to receive from the chargeable device a measurement of a first amount of energy received by the chargeable device over a first period of time. The apparatus further includes a processor configured to measure a second amount of energy provided by the antenna over a second period of time, compare the first amount of energy to the second amount of energy, and determine whether another object is absorbing power provided via the antenna based at least in part on comparing the first amount and the second amount of energy.