Wireless Charging Coil Covers With Lorentz-Force Foreign Object Removal
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Solution Overview
Problem
In wireless charging systems, foreign objects attached to transmission/reception coils can cause accidents due to induced currents and heat generation, and existing detection methods are inadequate, especially in low-power systems where small metal objects are difficult to detect as charging output increases.
Innovation Solution
A wireless charging system that uses a DC conducting wire attached to the transmission/reception coil covers, which applies a current perpendicular to a magnetic field to create a vibratory motion, efficiently removing foreign objects by Lorentz's force or Fleming's left-hand rule, with a sensor and switch to control the current supply based on object presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wireless charging output is increased to tens of watts or greater, then charging efficiency is improved, but detection ability of small metal foreign objects significantly decreases
Solution Approach 1:
The patent introduces a DC conducting wire as an intermediary component that generates a magnetic field to interact with foreign objects. This mediator enables detection and removal of small metal objects through electromagnetic interaction, solving the detection limitation at high power levels without requiring direct measurement of the foreign objects themselves.
Solution Approach 2:
The patent replaces traditional electrical detection methods (voltage and current measurement) with a magnetic field-based approach using DC conducting wires. This substitution allows detection through electromagnetic interaction rather than electrical circuit measurements, enabling detection of small metal objects that are invisible to conventional electrical methods at high power levels.
2Power
If metallic foreign object is attached to coil unit, then induced current is generated causing heat generation, but accident risk such as fire increases
Solution Approach 1:
The patent converts the harmful induced current phenomenon into a beneficial detection mechanism. By intentionally generating a magnetic field with DC conducting wires, the system creates controlled electromagnetic interaction with foreign objects, allowing detection and removal before dangerous heat generation occurs. The same electromagnetic principle that causes harm is used to prevent harm.
Solution Approach 2:
The patent performs preliminary detection and removal of foreign objects using DC conducting wires before wireless charging operates at high power levels. This preliminary action prevents the formation of induced currents that would lead to heat generation and fire risks, addressing the problem before it can manifest as a hazard.
3Reliability
If sensor and switch are added to detect and remove foreign objects, then safety is improved, but device complexity increases
Solution Approach 1:
The DC conducting wire serves multiple functions: it generates the magnetic field for wireless charging operation, detects the presence of foreign objects through electromagnetic interaction, and enables removal of foreign objects through controlled current application. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while maintaining improved 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
Effectively removes foreign objects with low power consumption, reducing the risk of accidents and design burdens on the charging system without affecting wireless charging efficiency.
Implementation Method 1
remove a foreign object attached to the transmission coil cover or the reception coil cover by using a force acting on the DC conducting wire according to a direction of a current flowing in the DC conducting wire and a direction of a magnetic field perpendicular to the direction of the current
Implementation Method 2
performing a vibratory motion in a rotational direction when a direction of an applied force is changed by an alternating current (AC) magnetic field applied to the wireless charging system
Data Source
AI summary
A wireless charging system, a method of removing a foreign object in the wireless charging system, and a computing device performing the method are provided. The wireless charging system includes a transmission coil cover mounted to surround a transmission coil of a transmission device, a reception coil cover mounted to surround a reception coil of a reception device, and a direct current (DC) conducting wire attached to each of the transmission coil cover and the reception coil cover, wherein the wireless charging system may be configured to remove a foreign object attached to the transmission coil cover or the reception coil cover by using a force acting on the DC conducting wire according to a direction of a current flowing in the DC conducting wire and a direction of a magnetic field perpendicular to the direction of the current.