Wireless power transmitter
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Solution Overview
Problem
Existing wireless power transmission systems 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 transmitter and receiver.
Innovation Solution
A wireless power transmitter that dynamically calibrates the measured quality factor value based on the shift of the current peak frequency from a reference peak frequency, calculates a quality factor slope, and compares it with predetermined thresholds to accurately detect foreign objects, stopping power transfer if necessary and providing a warning alarm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless power transmission is performed using electromagnetic induction or resonance, then power can be transferred wirelessly to mobile 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 by measuring quality factor changes before initiating full power transmission. This preliminary detection action identifies potential foreign objects in the charging area, allowing the system to prevent or adjust power transmission to avoid heating these objects while still enabling wireless charging when safe.
2Device complexity
If quality factor measurement is performed at a fixed reference frequency, then the detection method is simple, but frequency shifts reduce the accuracy of foreign object detection
Solution Approach 1:
The system dynamically adjusts the quality factor measurement frequency to track the peak frequency of the resonant circuit. Instead of using a fixed reference frequency, the measurement frequency adapts to frequency shifts caused by different receiver devices or environmental conditions, maintaining detection accuracy while accounting for system variability.
Solution Approach 2:
The system changes the operating frequency parameter to match the peak frequency where the quality factor is maximum. By adjusting the measurement frequency to follow the resonant peak rather than using a predetermined fixed frequency, the system maintains optimal detection sensitivity despite frequency drifts in the wireless power transmission system.
3Productivity
If foreign object detection is not performed, then the charging process is faster and simpler, but power waste and overheating may occur reducing system reliability
Solution Approach 1:
The system performs a quick quality factor measurement at the peak frequency before initiating full power transmission. This preliminary check rapidly identifies foreign objects, allowing the system to either proceed with charging or alert the user to remove foreign objects, thus preventing power waste and overheating while minimizing impact on charging speed.
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 risks by adaptively applying detection methods based on quality factors and peak frequencies, ensuring safe and efficient charging.
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
The electromagnetic resonance method uses an electric field or a magnetic field instead of using electromagnetic waves or current
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.