Wireless Power Transmitter Peak Shift Detection for Foreign Objects
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Solution Overview
Problem
Existing wireless charging technologies face challenges in accurately detecting foreign objects in the charging area, leading to reduced efficiency and potential overheating due to increased ambient temperature, which can damage the wireless power transmitter and receiver.
Innovation Solution
A method for detecting foreign objects by dynamically calibrating a measured quality factor value based on the shift of a current peak frequency from a reference peak frequency, calculating a quality factor slope, and comparing it with predetermined thresholds to accurately identify the presence of foreign objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a wireless power transmitter uses electromagnetic induction or resonance to transfer power wirelessly, then power transfer capability and convenience are improved, but the risk of foreign object heating and energy loss increases
Solution Approach 1:
The system performs foreign object detection before initiating full power transfer by measuring quality factor at peak frequency. This preliminary detection identifies potential foreign objects that could heat up, allowing the system to prevent power transfer to areas with foreign objects present
Solution Approach 2:
The system continuously monitors the quality factor of the resonant circuit during power transfer and compares it against reference values. When quality factor deviation exceeds thresholds, the system provides feedback to control the power transmitter to reduce or stop power output, preventing foreign object heating
2Measurement precision
If the wireless power transmitter continuously monitors quality factor to detect foreign objects, then detection accuracy is improved, but system complexity and measurement time increase
Solution Approach 1:
Instead of continuous full-spectrum monitoring, the system performs quality factor measurement only at the peak frequency of the resonant circuit. This partial measurement approach achieves sufficient detection accuracy while minimizing measurement time and computational complexity
Solution Approach 2:
The system dynamically adjusts the frequency at which quality factor is measured based on the actual peak frequency of the resonant circuit. By tracking and measuring at the varying peak frequency rather than a fixed frequency, the system maintains high detection accuracy despite changes in loading conditions
3Productivity
If foreign objects are present in the charging area, then power transfer may continue without interruption, but energy loss and overheating occur
Solution Approach 1:
The system monitors quality factor during power transfer and uses this feedback to detect foreign objects. When a foreign object is detected through quality factor analysis, the system automatically interrupts or reduces power transfer, preventing energy waste and potential damage
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 method enhances the accuracy of foreign object detection, minimizing power waste and overheating by adaptively applying foreign object detection methods based on quality factors and peak frequencies, thereby improving system safety and efficiency.
Implementation Method 1
Wireless power transmission or wireless energy transfer refers to technology for wirelessly transmitting electric energy from a transmitter to a receiver using the magnetic induction principle
Implementation Method 2
attempts have been made to radiate electromagnetic waves such as high frequencies, microwaves and lasers to transfer electric energy
Implementation Method 3
The electromagnetic resonance method uses an electric field or a magnetic field instead of using electromagnetic waves or current
Implementation Method 4
This technology is a RF wireless power transmission method using a rectenna. The rectenna is a combination of an antenna and a rectifier and means an element for directly converting RF power into DC power
Data Source
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AI summary
The present invention relates to a method for detecting foreign material, and an apparatus and a system therefor, and a method for detecting foreign material in a wireless power transmitter, according to one embodiment of the present invention, comprises the steps of: measuring a quality factor value, which corresponds to a reference operation frequency, when an object is sensed; searching for a current peak frequency having a maximum quality factor value within an operation frequency band; receiving, form a wireless power receiver, a foreign material detection state packet including information on a reference peak frequency; correcting the measured quality factor value by using a difference value between the current peak frequency and the reference peak frequency; and determining whether the foreign material exists by comparing the corrected quality factor value with a predetermined quality factor threshold value. Therefore, the present invention has an advantage of enabling foreign material to be more effectively and accurately detected.