Wireless Power Transmitter Calibration for Stable Foreign Object Detection
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in accurately detecting foreign objects due to unstable transmission and received power caused by fluctuations in switching circuit operation and misalignment of power receiving devices, leading to potential false detections or missed detections.
Innovation Solution
A power transmitting apparatus that measures transmission and received power in multiple states, calculates a parameter for foreign object detection, and determines the presence of unintended objects based on stable power readings, ignoring unstable measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power transmitting apparatus uses a switching circuit to convert DC voltage to AC voltage for wireless power transmission, then the power transmission capability is improved, but the transmission power becomes unstable due to fluctuations in switching circuit operation
Solution Approach 1:
The system performs a calibration process before actual power transmission to establish baseline parameters. The calibration obtains transmission power and received power values in two different states (with and without power receiving apparatus), calculates power loss characteristics, and stores these as reference data. This preliminary action enables the system to account for switching circuit fluctuations during subsequent foreign object detection by comparing against calibrated baseline values rather than using fixed thresholds.
2Adaptability or versatility
If the power receiving apparatus is placed on the power transmitting apparatus, then wireless charging function is enabled, but vibrations or misalignment may cause received power to become unstable
Solution Approach 1:
The system dynamically adjusts the foreign object detection threshold based on real-time operating conditions. Instead of using a fixed threshold, the detection mechanism continuously references the calibrated power loss parameters and adapts to variations in coupling efficiency, misalignment, and vibration effects. This dynamic approach allows the system to maintain accurate foreign object detection despite changes in power receiving apparatus position or stability.
3Loss of time
If the calibration process uses transmission power and received power values obtained during unstable operating conditions, then the calibration is completed quickly, but the foreign object detection accuracy deteriorates
Solution Approach 1:
The system implements a feedback mechanism that monitors the stability of transmission power and received power during calibration. The control unit evaluates whether the measured values are stable before finalizing the calibration parameters. If instability is detected (indicating switching circuit fluctuations or misalignment), the system can either discard the calibration data and request re-calibration under better conditions, or use the calibration data with adjusted confidence levels. This feedback ensures that calibration parameters are only accepted when they meet stability criteria, preventing inaccurate foreign object detection.
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
Enhances the accuracy of foreign object detection by stabilizing power measurements, reducing false positives and negatives in wireless power transmission systems.
Implementation Method 1
a power transmitting unit configured to wirelessly transmit power to a power receiving apparatus
Data Source
AI summary
A power transmitting apparatus, in a case where at least one of a transmission power measured in one state from among a plurality of different states or a received power obtained in the one state is unstable, does not use the transmission power and the received power in calculating the parameter used in determining whether or not an object not an intended power transmission target exists.