Wireless Charging Impedance Detection and Power Throttling
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Solution Overview
Problem
Wireless charging systems face overheating issues when metallic objects, such as thin CDs or DVDs, are present in the chargeable area due to magnetic field interactions, and conventional magnetic resonance methods may fail to charge these objects effectively.
Innovation Solution
A wireless charging system employing a magnetic resonance unit, impedance detection, and a power throttle module to monitor and adjust output power based on detected impedance values, ensuring safe charging by reducing or stopping power transmission when excessive impedance is detected, thereby preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic resonance is used for wireless charging, then charging efficiency is improved and most metallic objects are not overheated, but thin metallic objects such as CDs or DVDs may still suffer overheating
Solution Approach 1:
The system performs preliminary detection of metallic objects in the charging area before initiating full wireless charging. The controller detects the presence and type of metallic objects, then pre-adjusts charging parameters or issues warnings to prevent overheating before it occurs
Solution Approach 2:
The system continuously monitors temperature and charging parameters during the charging process. When abnormal heating is detected, the controller automatically adjusts or stops charging to prevent overheating, creating a closed-loop control system that responds to real-time conditions
2Productivity
If conventional wireless charging is used, then charging is simple and fast, but metallic objects in the chargeable area cause overheating due to eddy current
Solution Approach 1:
The system performs preliminary detection of metallic objects in the charging area before initiating full wireless charging. The controller detects the presence and type of metallic objects, then pre-adjusts charging parameters or issues warnings to prevent overheating before it occurs
Solution Approach 2:
The system continuously monitors temperature and charging parameters during the charging process. When abnormal heating is detected, the controller automatically adjusts or stops charging to prevent overheating, creating a closed-loop control system that responds to real-time conditions
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 system effectively prevents overheating in the presence of metallic objects and ensures reliable charging of devices with thin metallic components, maintaining normal charging operations while safely managing impedance variations.
Implementation Method 1
a power provision module of the charger and a power reception module of the appliance have to be placed in proximity (i.e., chargeable area) so as to achieve induction and magnetic coupling between the modules' coils
Implementation Method 2
Wireless charging transfers power by induction means between a charger and an appliance to be charged
Implementation Method 3
if a metallic object is within the chargeable area, the metallic object would be influenced by the magnetic field and eddy current may be produced, causing the metallic object or the power provision module to heat up
Data Source
AI summary
The wireless charging system includes a base member for placing a to-be-charged device, a wireless power transmission module for wireless charging the to-be-charged device through a magnetic resonance unit, an impedance detection module, a power throttle module, an information reception module. Through the wireless charging system, firstly, the to-be-charged device is wireless charged on the base member. Secondly, when the to-be-charged device is not a desired object and reveals a higher impedance value, the impedance detection module would detects this and inhibits/throttles the wireless power transmission module. Thirdly, if the to-be-charged object is a desired one but attached with some metallic object such as a metallic back cover, the wireless charging system may continue wireless charging according to the impedance information from the wireless reception module.