Wireless Power Feeder Phase Detection Frequency Tracking
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Solution Overview
Problem
Existing wireless power feeding technologies, particularly the magnetic field resonance type, face challenges in stabilizing output power due to changes in resonance frequency and interference from magnetic fields, making it difficult to maintain efficient power transmission.
Innovation Solution
A wireless power feeder system that includes a power transmission control circuit, a feeding coil circuit with a capacitor, a phase detection circuit, and a signal receiving circuit, which adjusts the drive frequency to track the resonance frequency and stabilize output voltage by detecting phase differences and adjusting voltage or current phases based on output signals from the receiving side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If magnetic field resonance type wireless power feeding is used to achieve high power transmission efficiency in intermediate range, then power transmission efficiency is improved, but resonance frequency changes due to positional relationship between coils making output power unstable
Solution Approach 1:
The patent implements a feedback control mechanism where the receiving coil detects the resonance frequency and feeds back control signals to the transmitting coil. The transmitting coil adjusts its drive frequency based on these feedback signals to track the resonance frequency dynamically, thereby maintaining stable output power and high transmission efficiency despite changes in coil positioning.
Solution Approach 2:
The system transitions from a static fixed-frequency approach to a dynamic frequency-tracking approach. The drive frequency is continuously adjusted to follow the resonance frequency changes caused by varying positional relationships between transmitting and receiving coils, ensuring optimal power transfer under dynamic conditions.
2Device complexity
If resonance frequency is set to a fixed value to simplify control, then device complexity is reduced, but power transmission efficiency deteriorates when resonance frequency changes
Solution Approach 1:
A feedback loop is established where the receiving coil monitors the actual resonance frequency and sends control signals back to the transmitting coil. This allows the system to automatically adjust the drive frequency to match the resonance frequency without requiring complex manual tuning or predetermined frequency settings.
Solution Approach 2:
The receiving coil actively participates in the control process by detecting the resonance frequency and generating feedback signals. The system essentially self-regulates by using the receiving end's detection capabilities to guide the transmitting end's frequency adjustment, eliminating the need for external frequency calibration.
3Power
If magnetic field generated by feeding or receiving coil is used for power transmission, then wireless power transfer is achieved, but signal transmission from coil L4 to coil L3 is affected by the magnetic field
Solution Approach 1:
The patent uses light signals as an intermediary medium for communication between the transmitting and receiving coils. Instead of using electromagnetic waves that could be interfered with by the magnetic field, the system converts control signals into light signals for transmission, thereby avoiding magnetic field interference and ensuring reliable signal communication.
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
This solution effectively maintains constant power transmission efficiency and stabilizes output voltage even when the resonance frequency changes, ensuring reliable and efficient wireless power transfer.
Implementation Method 1
When the feeding coil generates a magnetic field to cause the feeding coil and receiving coil to magnetically resonate, large current flows in the receiving coil
Implementation Method 2
When AC power is fed to the exciting coil, current also flows in the feeding coil according to the principle of electromagnetic induction
Data Source
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AI summary
Power is fed from a feeding coil L2 to a receiving coil L3 by magnetic resonance. A VCO 202 alternately turns ON/OFF switching transistors Q1 and Q2 at a drive frequency fo, whereby AC power is fed to the feeding coil L2, and then the AC power is fed from the feeding coil L2 to the receiving coil L3. A phase detection circuit 114 detects a phase difference between the current phase and voltage phase, and the VCO 202 adjusts the drive frequency fo such that the phase difference becomes zero. When load voltage is changed, the detected current phase value is adjusted with the result that the drive frequency fo is adjusted.