Wireless Power Coil Calibration Using Q-Factor FOD Validation
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Solution Overview
Problem
Existing foreign object detection (FOD) systems in wireless power transmission suffer from systematic biases that degrade accuracy due to inaccurate parameter calculation during calibration, especially when a foreign object is present during calibration.
Innovation Solution
The electronic device controls power application to a coil, identifies Q-factors during power-off periods, and verifies parameter validity based on these Q-factors to ensure accurate calibration and enhance FOD accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed to remove systematic bias and improve FOD accuracy, then measurement precision is improved, but if a foreign object is present during calibration, inaccurate parameters are obtained which degrades FOD accuracy
Solution Approach 1:
The system performs a preliminary Q-factor measurement before calibration to establish a reference value. This preliminary action allows the system to detect foreign objects that may be present during calibration, preventing inaccurate parameter acquisition while maintaining the ability to perform bias removal calibration when conditions are appropriate.
Solution Approach 2:
The system uses the Q-factor as a feedback parameter to monitor the calibration process. By comparing the Q-factor before and during calibration, the system can detect changes indicating foreign object presence and adjust or abort the calibration process accordingly, ensuring parameter validity while maintaining FOD accuracy.
2Measurement precision
If Q-factor measurement is performed during power-off periods to verify parameter validity, then measurement precision is improved, but additional time is required for power cycling and measurement
Solution Approach 1:
The system uses periodic power-off periods during the calibration process to perform Q-factor measurements. These periodic interruptions are strategically timed to verify parameter validity without requiring extensive additional calibration time, balancing measurement precision with time 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 method secures the validity of calibration parameters, enhancing the accuracy of foreign object detection by ensuring accurate identification of Q-factors during power transmission.
Implementation Method 1
an electronic device for wirelessly transmitting power may apply a ping signal to a coil
Implementation Method 2
identify a first Q-factor during the first period, control the power transmitting circuit to apply, to the coil, a second power during a calibration operation for identifying at least one parameter used for identifying a power loss
Data Source
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AI summary
An electronic device includes a power transmitting circuit configured to transmit power to a wireless power receiver, a communication circuit configured to perform communication with the wireless power receiver, and a control circuit configured to control the power transmitting circuit to apply first power to a coil of the power transmitting circuit, control the power transmitting circuit to stop applying the first power and to prevent power from being applied to the coil during a first period, identify a first Q-factor during the first period, control the power transmitting circuit to apply, to the coil, a second power based on a calibration operation for identifying at least one parameter used for identifying a power loss during power transmission, control the power transmitting circuit to stop applying the second power and to prevent power from being applied to the coil during a second period, identify a second Q-factor during the second period, and identify a validity of the at least one parameter based on the first Q-factor or the second Q-factor.