Wireless Power Coil Tuning With Movable Magnetic Body Feedback
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Solution Overview
Problem
Wireless power transmission devices face efficiency issues due to changes in impedance and resonant frequency when metal-containing wireless power reception devices approach, caused by decreased inductance of the transmission coil, leading to high voltage and current challenges, and parasitic capacitance affecting Q factor and energy loss.
Innovation Solution
A wireless power transmission device with a magnetic body and motor system adjusts the distance between the transmission coil and magnetic body to compensate for impedance changes, using an impedance sensor and processor to control the motor based on detected impedance differences, enabling efficient impedance matching and wireless charging in a 3D space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high current flows through the transmission coil to form a strong magnetic field for space wireless charging, then wireless power transmission capability is improved, but impedance changes and energy loss increase
Solution Approach 1:
The patent applies parameter changes by adjusting the distance between the magnetic body and transmission coil based on detected impedance changes. When impedance changes are detected, the system dynamically modifies the physical parameter (distance) to optimize the magnetic coupling and reduce energy loss while maintaining effective power transmission capability.
2Adaptability or versatility
If the distance between transmission coil and magnetic body is increased for space wireless charging, then charging space flexibility is improved, but impedance matching becomes difficult
Solution Approach 1:
The patent implements feedback control by using an impedance sensor to continuously monitor impedance changes in the resonance circuit. Based on the detected impedance variations, the processor controls the motor to adjust the magnetic body position, creating a closed-loop feedback system that maintains impedance matching despite changes in charging space or device positioning.
3Adaptability or versatility
If switched capacitor circuit and switched coil circuit are used for impedance compensation, then impedance adjustment capability is improved, but device complexity and parasitic effects increase
Solution Approach 1:
The patent extracts the impedance compensation function from complex switched capacitor/inductor circuits and implements it through a simpler mechanical adjustment system. By removing the need for complex electronic switching circuits and replacing them with motor-driven magnetic body positioning, the system achieves impedance compensation with reduced circuit complexity and fewer parasitic effects.
4Productivity
If resonance circuit is used for wireless power transmission, then power transmission efficiency is improved, but impedance changes due to metal objects reduce efficiency
Solution Approach 1:
The patent applies dynamics by transitioning from a static resonance circuit to a dynamic system that actively adjusts the magnetic body position in response to impedance changes. This dynamic adjustment allows the system to adapt to varying loading conditions and maintain optimal resonant coupling, thereby preserving power transmission efficiency and resonant frequency stability even when metal objects are present.
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 compensates for impedance changes, ensuring efficient wireless power transmission to multiple devices in a 3D space by adjusting the magnetic body's position, maintaining resonant frequency and reducing energy loss.
Implementation Method 1
A wireless power transmission device may transmit wireless power to a wireless power reception device (e.g., a smartphone) through resonance
Implementation Method 2
an impedance sensor configured to detect impedance based on a voltage and a current measured at a first point of the wireless power transmission device
Data Source
AI summary
A wireless power transmission device is provided. The wireless power transmission device includes a transmission coil including a first member, which has one end and the other end forming a first angle with a plane, and a second member, which is arranged on the plane and is connected to each of the one end and the other end of the first member, an impedance sensor for outputting a voltage value corresponding to an impedance change amount of a resonance circuit, which includes the transmission coil, a magnetic body having a side surface that is dented, the dented side surface facing a portion of the transmission coil, a motor for moving the magnetic body, memory storing one or more computer programs, and one or more processors communicatively coupled to the memory, wherein the one or more computer programs include computer-executable instructions that, when executed by the one or more processors individually or collectively, cause the wireless power transmission device to receive the output voltage value from the impedance sensor, calculate the difference value between a reference voltage value and the received voltage value, determine control information about the motor on the basis of the calculated difference value, and drive the motor through the determined control information so as to control the distance between the magnetic body and the portion of the transmission coil.