Wireless Power Transmission Frequency Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-contact power transmission technologies face challenges in maintaining high efficiency and stability, particularly with high-frequency switching power sources, where neutral impedance regions can damage circuit parts and efficiency is not maximized when frequencies are set based on impedance phase or magnitude.
Innovation Solution
A power transmission device that wirelessly transmits alternating current power by setting the frequency of alternating voltage to the higher of either the frequency at which transmission efficiency is highest or the frequency at which the voltage generated in the power receiving device is highest, using a control circuit to manage the frequency within a predetermined range and adjust the duty ratio of switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the frequency of AC power is set to the frequency at which the phase of the impedance is zero, then impedance matching is improved, but circuit stability deteriorates and circuit parts may be damaged
Solution Approach 1:
The patent changes the frequency parameter from the traditional zero-phase-point frequency to a frequency where the impedance phase leads by a predetermined angle. This parameter change resolves the contradiction by avoiding the neutral zone while maintaining impedance matching effectiveness, thus preventing circuit damage while achieving reliable power transmission.
Solution Approach 2:
The patent applies preliminary anti-action by proactively avoiding the zero-phase-point frequency region where circuit damage occurs. The control circuit is designed to set the frequency to lead the zero-phase-point by a predetermined angle, preventing the harmful effect before it can occur, rather than reacting after damage happens.
2Reliability
If the frequency of AC power is set to the frequency at which the absolute value of the impedance is a minimum, then impedance matching is improved, but transmission efficiency is not maximized
Solution Approach 1:
The patent changes the frequency selection criterion from minimum impedance magnitude to a frequency where the phase leads by a predetermined angle. This parameter change allows the system to achieve both good impedance matching and maximum transmission efficiency, as the frequency point where phase leads by a predetermined angle corresponds to the resonant frequency where transmission efficiency is highest.
3Power
If high-frequency switching power source is used, then power transmission capability is improved, but circuit stability deteriorates in the neutral zone
Solution Approach 1:
The patent applies preliminary anti-action by designing the control circuit to avoid the unstable neutral zone frequency region. By setting the operating frequency to lead the zero-phase-point by a predetermined angle, the system proactively prevents the instability and potential damage that would occur in the neutral zone, allowing high-frequency switching power sources to operate safely and effectively.
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 approach enhances power transmission efficiency and stability, preventing malfunctions like overcurrent or overvoltage and ensuring circuit safety by optimizing frequency settings and duty ratios, thereby maintaining high efficiency and stable power feeding.
Implementation Method 1
a power conversion circuit that outputs an alternating voltage in order to generate an alternating magnetic field
Data Source
AI summary
A power transmission device includes a power conversion circuit that outputs an alternating voltage in order to generate an alternating magnetic field and a control circuit used to control a frequency of the alternating voltage. The control circuit sets, in a predetermined frequency range, the frequency of the alternating voltage to a higher one of a first frequency at which transmission efficiency is highest and a second frequency at which a voltage generated in the power receiving device is highest, and performs power transmission.