Wireless Charging Coil Selection With Foreign Object Power Control
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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 high-power transmission.
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 differentiate between the presence and absence of foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wireless power transmission is performed at high power without accurate foreign object detection, then power transmission efficiency is maintained, but device damage may occur due to overheating from foreign objects
Solution Approach 1:
The system performs foreign object detection before initiating high-power transmission by measuring quality factor during a negotiation phase. This preliminary detection prevents foreign objects from being exposed to high power that would cause overheating, while allowing efficient charging when no foreign objects are present.
Solution Approach 2:
The system continuously monitors quality factor changes during power transmission and adjusts power levels accordingly. When quality factor indicates foreign object presence, the system reduces or stops power transmission to prevent overheating, while maintaining high power efficiency when quality factor remains within normal ranges.
2Productivity
If foreign object detection is performed using simple methods, then detection speed is fast, but detection accuracy is low leading to false positives and unnecessary charging stops
Solution Approach 1:
The system performs an initial quality factor measurement during the negotiation phase before power transmission begins. This preliminary measurement establishes a baseline quality factor value that is used to determine whether foreign objects are present, enabling fast detection without sacrificing accuracy.
Solution Approach 2:
The system dynamically adjusts the quality factor threshold for foreign object detection based on the specific charging scenario and device characteristics. Rather than using a fixed threshold, the system adapts the detection criteria to minimize false positives while maintaining detection sensitivity, thereby improving both speed and 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 solution enhances the accuracy of foreign object detection, prevents device damage by adjusting power transmission accordingly, and ensures seamless charging by minimizing unnecessary stops and maintaining optimal power levels.
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
utilizing sensors to measure power loss and temperature changes to accurately differentiate between the presence and absence of foreign objects
Implementation Method 3
utilizing sensors to measure power loss and temperature changes to accurately differentiate between the presence and absence of foreign objects
Data Source
AI summary
A method of transmitting power of a wireless power transmitter, including a phase of sequentially transmitting a detection signal to a wireless power receiver a plurality of times through a plurality of transmission coils to detect that the wireless power receiver is present; a phase of identifying a transmission coil that has received the signal strength indicator transmitted from the wireless power receiver in response to the detection signal transmitted a plurality of times; a phase of selecting, as a power transmission coil, a transmission coil that has received the signal strength indicator having the most or largest value among the plurality of transmission coils that have received the signal strength indicator as a power transmission coil; a phase of receiving an FOD status packet from the wireless power receiver; a first determination phase of determining whether a foreign object is present in a charging area of the wireless power transmitter based on the FOD status packet; and a power control phase of controlling power transmission in a first power transfer mode when it is determined in the first determination phase that the foreign object is present in the charging area, or controlling the power transmission in a second power transfer mode when it is determined in the first determination phase that the foreign object is not present in the charging area.