Wireless Charger Misalignment Detection and Threshold Adjustment
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Solution Overview
Problem
Existing wireless charging systems often incorrectly terminate charging due to misalignment between the charger and device, leading to false positives in foreign object detection, which can result in inappropriate cessation of charging.
Innovation Solution
The system employs techniques such as alignment coils to determine misalignment, adjusts power difference thresholds based on prior charging history, uses case identifiers, and incorporates sensing techniques to differentiate between misalignment and foreign objects, allowing for adaptive power management to prevent unsafe heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the system uses a fixed power difference threshold to detect foreign objects, then safety is improved by preventing foreign object heating, but false positives increase causing inappropriate termination of charging due to misalignment
Solution Approach 1:
The system dynamically adjusts the power difference threshold based on real-time coupling conditions and charging history rather than using a fixed threshold. The threshold adapts to different alignment scenarios, allowing higher thresholds when misalignment is detected and lower thresholds when alignment is optimal, thereby reducing false positives while maintaining safety
Solution Approach 2:
The system incorporates feedback loops that continuously monitor charging parameters, alignment status, and power transfer efficiency. This feedback is used to update the power difference threshold adaptively and to distinguish between power loss due to misalignment versus power absorption by foreign objects, preventing inappropriate charging termination
2Productivity
If the system reduces transmission power to tolerate misalignment, then charging continuity is improved, but power transfer efficiency decreases
Solution Approach 1:
The system dynamically adjusts transmission power levels based on detected misalignment rather than maintaining a fixed low power level. When misalignment is detected, the system reduces power to acceptable levels to prevent excessive heating, but maintains higher power when alignment is optimal, thereby preserving overall power transfer efficiency while ensuring charging continuity
Solution Approach 2:
The system changes operational parameters (transmission power level, frequency, etc.) in response to detected misalignment conditions. By adjusting these parameters adaptively, the system optimizes the balance between charging continuity and power transfer efficiency, avoiding unnecessary energy loss while maintaining safe operation
3Reliability
If the system uses alignment coils to detect misalignment, then false positives are reduced, but device complexity increases
Solution Approach 1:
The alignment coils serve multiple functions: they detect misalignment, provide feedback for threshold adjustment, and enable adaptive power management. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity while achieving improved foreign object detection accuracy
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 reliability of wireless charging by reducing false terminations and ensuring safe operation even under conditions of misalignment, thereby maintaining charging when it is safe to do so.
Implementation Method 1
Inductive wireless charging systems enable a charger to recharge a battery-powered electronic device by transmitting a wireless power signal (e.g., in the form of an AC magnetic field)
Implementation Method 2
a portion of the transmitted power signal may also be received and absorbed by metal or other objects (e.g., 'foreign objects') that are within inductive coupling range of the wireless charger, resulting in heating of the foreign object
Data Source
AI summary
Methods, systems, and techniques for safely controlling wireless charging in the presence of a foreign object are presented. A method includes determining a power difference between a power transmitted by a wireless charger and a power received by an electronic device, determining a level of misalignment of the electronic device with respect to the wireless charger; estimating an amount of power difference due to the level of misalignment of the electronic device with respect to the wireless charger, adjusting a power difference threshold for the wireless charger based on the estimated amount of power difference, and controlling operation of the wireless charger based on the power difference and the adjusted power difference threshold.