Wireless Charging Power Loss Control for Foreign Object Heating
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in safely charging electronic devices when foreign objects, including both metal objects and components of the receiver, are present on the charging surface, as they can cause excessive heating due to power signal absorption, leading to inefficient charging and potential damage.
Innovation Solution
Implementing a closed loop power loss control mechanism that dynamically adjusts the transmitted power using proportional integral (PI), proportional integral derivative (PID), or proportional control to regulate power loss within acceptable ranges, preventing overheating of foreign objects while maintaining effective charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wireless power transmitter increases transmitted power to improve charging performance, then charging efficiency is improved, but foreign object heating increases causing safety issues
Solution Approach 1:
The patent implements a closed-loop feedback control system that continuously monitors power loss and adjusts transmitted power accordingly. The foreign object detector measures power loss, compares it to a threshold, and feeds this information back to the controller which then modulates the transmitted power to maintain safety while optimizing charging efficiency.
Solution Approach 2:
The system dynamically adjusts the transmitted power level based on real-time foreign object detection results. Rather than using a fixed power level, the controller continuously modulates the power transmission according to the detected power loss, enabling adaptive optimization of charging efficiency while preventing foreign object heating.
2Object-affected harmful factors
If the wireless power transmitter reduces transmitted power to prevent foreign object heating, then safety is improved, but charging efficiency decreases
Solution Approach 1:
The closed-loop feedback system allows the transmitter to operate at high power levels when no foreign objects are present (maintaining charging efficiency) and automatically reduce power only when foreign objects are detected (preventing heating). This selective power adjustment resolves the contradiction by using feedback to determine when power reduction is necessary.
Solution Approach 2:
The system changes the power transmission parameter dynamically based on foreign object detection status. When power loss exceeds the threshold indicating foreign object presence, the controller changes the transmitted power parameter to a lower level, thereby preventing heating while maintaining high efficiency during normal operation.
3Device complexity
If the wireless power transmitter uses simple foreign object detection to reduce system complexity, then device complexity is reduced, but measurement precision of power loss decreases
Solution Approach 1:
The system uses the inherent power loss in the wireless power transmission system itself as the detection mechanism for foreign objects. Rather than requiring separate complex sensing hardware, the transmitter monitors its own power efficiency and infers foreign object presence from power loss measurements, thereby maintaining simple device architecture while achieving adequate measurement precision for safety.
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 solution balances charging performance with safety by continuously monitoring and adjusting power transmission to prevent excessive heating of foreign objects, ensuring reliable and safe wireless charging even in the presence of friendly or non-friendly foreign objects.
Implementation Method 1
A voltage or current applied to the transmitter coil causes the transmitter coil to transmit a power signal in the form of a magnetic flux which couples with a receiver coil of the wireless power receiver to transmit power
Implementation Method 2
The power signal transmitted by the wireless power transmitter affects the FO. In particular, the power signal generates eddy currents in the FO and heating of the FO
Data Source
AI summary
Power transmission associated with wireless charging of a battery of an electronic device or powering of the electronic device comprises determining a power loss associated with transmitting a power signal having a transmitted power from the wireless power transmitter to a wireless power receiver. A closed loop power loss control based on the power loss is performed which comprises outputting a target transmit power to meet a power loss limit. The power signal having the target transmit power is wirelessly transmitted to the wireless power receiver to charge the battery of the electronic device or power the electronic device and balance charging performance and safety.