Wireless Charging Position Detection for Accurate Foreign Object Sensing
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Solution Overview
Problem
Current wireless charging technologies lack accurate detection of foreign objects, particularly metal objects, due to their inability to consider the relative position between the transmit and receive ends, leading to safety issues like overheating and potential fires.
Innovation Solution
A wireless charging apparatus and method that utilizes a controller to determine the relative position between the transmit and receive ends based on parameters such as self-inductance, current, efficiency, and direct current output voltage, allowing for accurate detection of foreign objects by calculating power losses and Q-values, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If foreign object detection is performed without considering relative position between transmit and receive ends, then detection process is simple, but detection accuracy is poor leading to safety issues
Solution Approach 1:
The patent replaces complex mechanical position sensing systems with electrical parameter measurements. By measuring self-inductance changes of the transmitting coil and electrical characteristics (current, voltage, efficiency) of both transmit and receive ends, the system infers relative position without mechanical sensors. This substitution maintains detection accuracy while reducing mechanical complexity.
Solution Approach 2:
The patent introduces electrical parameters (self-inductance, current, voltage, efficiency) as intermediary variables that indirectly reflect relative position. Instead of directly measuring position, the system measures these electrical intermediaries and uses their relationship to determine position and detect foreign objects, creating a indirect but accurate detection pathway.
2Measurement precision
If multiple parameters are measured to determine relative position, then position detection accuracy is improved, but measurement and calculation complexity increases
Solution Approach 1:
The patent makes existing wireless charging components multi-functional. The transmitting coil serves both power transmission and self-inductance measurement functions. The transmit and receive ends simultaneously perform power transfer and electrical characteristic measurements. This multi-functionality allows position detection using existing hardware without adding dedicated measurement devices, reducing overall system complexity.
Solution Approach 2:
The system continuously measures electrical parameters and uses feedback loops to determine relative position and detect foreign objects. By monitoring changes in self-inductance, current, voltage, and efficiency, the system provides real-time feedback on position and foreign object presence, enabling dynamic adjustment and accurate detection without complex one-time measurements.
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
The solution enables precise detection of foreign objects, reducing errors in power loss calculations and enhancing safety by preventing overheating and fires, thus improving the reliability of wireless charging systems.
Implementation Method 1
A principle of a wireless charging technology is to transmit electric energy through magnetic field coupling between a transmitting coil at a transmit end and a receiving coil at a receive end
Implementation Method 2
a changing magnetic field generated between the transmit end and the receive end may generate eddy current losses and heat in the metal foreign object
Data Source
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AI summary
This application discloses a wireless charging apparatus, a position detection method, and a system. The apparatus includes a transmit end or a receive end. The transmit end includes a transmit end resonant network and an inverter circuit, and the transmit end resonant network includes a transmitting coil. The receive end includes a receive end resonant network and a rectifier circuit, and the receive end resonant network includes a receiving coil. The apparatus further includes a controller, and the controller is configured to obtain a relative position between the transmit end and the receive end based on a self-inductance of the transmitting coil and at least one of the following parameters. The at least one parameter includes a current of the transmitting coil, efficiency of a wireless charging system formed by the transmit end and the receive end, and a direct current output voltage at the receive end. There is a single change relationship between the at least one parameter and the relative position. Therefore, the relative position between the transmit end and the receive end of wireless charging can be accurately detected.