Wireless Charging Coil Detection for Foreign Objects and Misalignment
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Solution Overview
Problem
Existing wireless power transmission standards, such as the Qi standard, struggle to distinguish between a misaligned wireless power receiving device and the presence of a foreign object in the charging area, leading to incorrect error notifications and potential safety issues due to heat generation, as they cannot accurately judge foreign object placement.
Innovation Solution
A wireless power transmitting device that utilizes a transmission coil, power providing circuit, and controller to identify resonant frequency differences and Q-factor variations, enabling precise detection of foreign objects and alignment of the receiving device by applying first and second powers for communication and response analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wireless power transmitting device uses Q-factor measurement to detect foreign objects during the standby phase, then it can identify the presence of objects in the charging area, but it cannot distinguish between a misaligned wireless power receiving device and a foreign object
Solution Approach 1:
The patent segments the detection process into multiple phases: standby phase (Q-factor measurement), negotiation phase (device identification through communication), and power transfer phase (continuous monitoring). By dividing the detection into阶段性 steps, the system can first detect any object presence using Q-factor, then identify whether it's a valid receiving device through negotiation-phase communication, and finally confirm proper alignment during power transfer, thereby resolving the ambiguity between foreign objects and misaligned devices
Solution Approach 2:
The patent performs preliminary device identification and alignment verification during the negotiation phase before initiating power transfer. By conducting communication-based device recognition and alignment checks in advance, the system establishes baseline information about the receiving device's presence and positioning, which then enables accurate foreign object detection during the power transfer phase without confusion
2Productivity
If the wireless power transmitting device continues power transfer when a foreign object is present, then power transmission efficiency is maintained, but overheating and safety issues occur
Solution Approach 1:
The patent implements continuous feedback monitoring during the power transfer phase by repeatedly measuring Q-factor and monitoring power loss. When the system detects abnormal Q-factor changes or excessive power loss indicating foreign object presence, it provides feedback to stop or reduce power transmission, thereby preventing overheating while maintaining efficient power transfer under normal conditions
Solution Approach 2:
The patent converts the harmful effect of foreign objects (which cause power loss and heating) into a useful detection mechanism. By monitoring the power loss and Q-factor changes caused by foreign objects, the system can identify their presence and take corrective action, thereby transforming a safety hazard into an opportunity for enhanced safety through intelligent detection and response
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
Enables accurate differentiation between foreign objects and misaligned receiving devices, ensuring safe and reliable wireless charging by preventing false error notifications and maintaining temperature within safety limits.
Implementation Method 1
a transmission coil (213), a power providing circuit (217, 218), and at least one controller (215)
Implementation Method 2
identify a resonant frequency, based on a voltage measured at the transmission coil (213) in response to the first power applied to the transmission coil (213)
Data Source
AI summary
According to an embodiment, a wireless power transmitting device may include a transmission coil, a power providing circuit, and at least one controller. The at least one controller may be configured to control the power providing circuit to apply first power to the transmission coil, identify a resonant frequency, based on a voltage measured at the transmission coil in response to the first power applied to the transmission coil, based on a difference between the identified resonant frequency and a reference frequency meeting a designated condition, identify that a foreign object is placed on a charging area of the wireless power transmitting device, and based on the difference between the identified resonant frequency and the reference frequency failing to meet the designated condition, control the power providing circuit to apply, to the transmission coil, at least one second power for performing communication with a wireless power receiving device.