Wireless Power Transmission Control for Accurate Foreign Object Detection
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Solution Overview
Problem
Current wireless charging technologies face challenges in accurately detecting foreign objects, leading to inefficient power transmission and potential device damage due to overheating, as they often incorrectly determine the presence of foreign objects, resulting in unnecessary charging stops or continued charging with reduced efficiency.
Innovation Solution
A method and apparatus for controlling wireless power transmission that includes a foreign object detection system using packet reception, determination phases, and adaptive power control, where power transmission modes are adjusted based on the presence of foreign objects, utilizing sensors to measure power loss and temperature changes to accurately detect and respond to foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wireless power transmission is performed using electromagnetic induction or resonance, then power can be transmitted wirelessly to devices, but foreign objects in the charging area may be heated due to induced electromagnetic signals
Solution Approach 1:
The system performs foreign object detection before initiating full power transmission. The transmitter first transmits detection signals to identify foreign objects in the charging area, then decides whether to proceed with power transmission based on the detection results, preventing foreign object heating before it occurs
Solution Approach 2:
The system continuously monitors parameters such as impedance changes, temperature variations, and power consumption during charging. Based on this feedback, the transmitter adjusts or stops power transmission when foreign objects are detected, resolving the contradiction between maintaining power transmission efficiency and preventing harmful heating effects
2Reliability
If foreign object detection is performed using existing methods, then safety can be improved, but detection accuracy is insufficient leading to false positives or missed detections
Solution Approach 1:
The detection process is divided into multiple phases: initial foreign object detection before power transmission, continuous monitoring during power transmission, and post-detection verification. Each phase uses different detection methods and parameters, improving overall detection accuracy while maintaining reliability
Solution Approach 2:
The system changes detection parameters such as frequency, power level, and measurement type based on the charging state. Different parameters are used at different stages to optimize detection accuracy for specific conditions, reducing false positives while maintaining high reliability
3Object-affected harmful factors
If power transmission is stopped when foreign objects are detected, then device safety is protected, but charging efficiency is reduced due to unnecessary stops
Solution Approach 1:
Instead of completely stopping power transmission upon detecting any foreign object, the system transmits detection signals at reduced power levels first. This partial action allows verification of whether the detected object is truly harmful, avoiding unnecessary charging interruptions while maintaining device safety
Solution Approach 2:
The system dynamically adjusts power transmission based on real-time detection results. When foreign objects are detected, power is reduced or stopped temporarily for verification, then restored if safe, creating a dynamic response that balances safety protection with charging efficiency
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 enhances the accuracy of foreign object detection, prevents device damage, and ensures seamless charging by dynamically adjusting power transmission, maintaining efficient energy transfer and reducing unnecessary charging stops.
Implementation Method 1
wireless power transmission or wireless energy transfer technology refers to technology of wirelessly transmitting electric energy from a transmitter to a receiver using the principle of magnetic induction
Implementation Method 2
If a conductor which is not a wireless power receiver—that is, a foreign object (FO)—is present in a wireless charging area, an electromagnetic signal received from a wireless power transmitter may be induced in the FO
Implementation Method 3
the temperatures of the wireless power receiver and the wireless power transmitter may increase due to increase in ambient temperature of the FO
Data Source
AI summary
A wireless power receiver of receiving power from a wireless power transmitter, including a receiving part configured to receive wireless power from the wireless power transmitter; and a main controller configured to generate a signal including an FOD status packet, wherein the main controller transmits a signal including the FOD status packet to the wireless power transmitter; wherein the main controller receives a first power from the wireless power transmitter when a NAK response indicating that a foreign object is present in a charging area of the wireless power transmitter is received from the wireless power transmitter, or receives a second power from the wireless power transmitter when an ACK response indicating that the foreign object is not present in the charging area of the wireless power transmitter is received from the wireless power transmitter, in response to the FOD status packet; and wherein the main controller receives a signal including information on a result of determining whether the foreign object is present in the charging area from the wireless power transmitter based on information other than information included in the FOD status packet by the wireless power transmitter while receiving the first power or the second power.