Wireless Power FOD Using Adaptive Offsets Across Charging Phases
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Solution Overview
Problem
Existing wireless power transfer systems are inadequate in detecting foreign metal objects, leading to safety hazards and efficiency disruptions due to undesired heating and interference.
Innovation Solution
Implementing a foreign object detection (FOD) assessment unit that initializes during the idle phase and adjusts detection values using offset values to accurately identify foreign objects across different operating phases, including an initial idle phase assessment and subsequent assessments that adapt to system changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional foreign object detection techniques are used in wireless power transfer systems, then the system structure remains simple, but the detection accuracy is insufficient leading to safety hazards
Solution Approach 1:
The FOD assessment unit is initialized during the idle phase before power transfer begins, performing foreign object detection in advance. The system sets an FOD flag to track whether assessment has been completed, ensuring detection occurs before the transmitter enters operational phases where foreign objects could cause harm.
Solution Approach 2:
The system implements continuous monitoring where the FOD assessment unit provides feedback about foreign object presence to the power transmitter. The FOD flag serves as a feedback mechanism that indicates whether detection has been performed and whether foreign objects are present, enabling the system to adjust its operation accordingly.
2Measurement precision
If foreign object detection is performed continuously across all operating phases, then detection accuracy improves, but energy consumption increases
Solution Approach 1:
The foreign object detection process is segmented into different operating phases: idle phase initialization and subsequent assessment phases. The FOD assessment unit is initialized during the idle phase, and the system transitions between phases based on whether foreign objects are detected, avoiding continuous monitoring and reducing energy consumption.
Solution Approach 2:
The system performs foreign object detection periodically at phase transitions rather than continuously. The FOD assessment is triggered at specific intervals corresponding to operating phase changes, maintaining detection accuracy while minimizing energy expenditure compared to continuous monitoring.
3Reliability
If the FOD assessment unit is initialized during the idle phase, then safety is enhanced by detecting foreign objects before power transfer, but the time to reach operational phase is extended
Solution Approach 1:
Foreign object detection is performed as a preliminary action during the idle phase before the power transmitter enters operational phases. This ensures that if foreign objects are present, they are detected before power transfer begins, preventing safety hazards while minimizing the time added to the overall process.
Solution Approach 2:
If no foreign objects are detected during the idle phase assessment, the system quickly transitions to the operational phase without unnecessary delays. The FOD flag mechanism allows the system to confirm safe operation and proceed efficiently, minimizing time loss while maintaining safety.
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 safety and reliability by accurately detecting foreign objects at various phases, preventing unwanted heating and maintaining efficient power transfer.
Implementation Method 1
The wireless power may be transferred using inductive coupling or resonant coupling between the Power Transmitter and the Power Receiver. For example, the Power Transmitter may include a primary coil that produces an electromagnetic field. The electromagnetic field may induce an electromotive force in a secondary coil of the Power Receiver when the secondary coil is placed in proximity to the primary coil.
Implementation Method 2
when a foreign metal object (such as a key, a coin, a metallic can, or aluminum foil, among other examples) is in proximity of the electromagnetic field, the foreign metal object may be undesirably heated up due to eddy currents.
Data Source
AI summary
This disclosure provides systems, methods and apparatuses for foreign object detection (FOD) in a wireless power transfer (WPT) system. An FOD protocol can be coordinated with different operating phases of the WPT system, such as an idle phase, a configuration phase, a connected phase, and a power transfer phase. An FOD assessment unit may perform foreign object detection assessments as part of each operating phase. The FOD protocol may include an initial idle phase foreign object detection assessment in the idle phase to handle a scenario in which a Power Receiver is placed on the Power Transmitter before the Power Transmitter has been turned on. The FOD assessment unit may adjust offset values used during each FOD assessment to improve accuracy of foreign object detection. The offset values may be adapted to accommodate movement of the Power Receiver after the initial idle phase foreign object detection assessment.