Wireless Power Feeder Phase Detection Resonance Control
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Solution Overview
Problem
Current 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, which affects signal transmission and efficiency.
Innovation Solution
A wireless power feeder system that includes a feeding coil circuit, a power transmission control circuit, a phase detection circuit, and a signal receiving circuit, which adjusts the drive frequency to maintain resonance and stabilize output voltage by detecting phase differences between voltage and current phases, and uses a signal receiving circuit to receive output signals from the receiving side to adjust the power transmission.
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 at intermediate range, then power transmission efficiency is improved, but output power stability deteriorates due to resonance frequency changes
Solution Approach 1:
The patent implements a feedback control mechanism where the receiving side detects output voltage magnitude and transmits this information back to the transmitting side. The transmitting side then adjusts the drive frequency based on this feedback to maintain resonance and stabilize output power, resolving the contradiction between maintaining high transmission efficiency and ensuring output stability despite resonance frequency changes.
Solution Approach 2:
The patent dynamically changes the drive frequency parameter in response to detected resonance frequency shifts. By adjusting the drive frequency to match the changing resonance frequency, the system maintains optimal power transmission efficiency while stabilizing output power, thus resolving the contradiction between efficiency and stability.
2Stability of the object's composition
If drive frequency is adjusted to maintain resonance and stabilize output voltage, then output power stability is improved, but system complexity increases due to additional control circuits
Solution Approach 1:
The patent integrates multiple functions into the existing wireless power transmission components. The transmitting and receiving coils serve both power transmission and signal communication functions. The phase detection and frequency adjustment mechanisms utilize the existing resonant circuitry, minimizing additional hardware while achieving stability control.
3Measurement precision
If phase detection circuit is added to detect phase difference between voltage and current, then power transmission control precision is improved, but device complexity increases
Solution Approach 1:
The patent utilizes the inherent phase relationship between voltage and current in the resonant circuit for detection purposes. The system leverages the natural phase shift that occurs during resonance, using existing circuit elements to generate detection signals without requiring entirely separate measurement hardware, thus improving precision while limiting complexity increase.
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 controls power transmission in wireless power feeding systems, maintaining constant efficiency and stability even when resonance frequencies change, and reduces interference from magnetic fields, ensuring reliable power delivery.
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
Implementation Method 3
a phase detection circuit that detects a phase difference between the voltage phase and current phase of the AC power
Implementation Method 4
a signal receiving circuit that receives an output signal indicating the magnitude of an output from the power receiving side
Data Source
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.