Active Variable Reactance Tuning for Fixed-Frequency LC Resonators
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Solution Overview
Problem
Resonant wireless power systems face challenges in achieving high efficiency due to the need for precise control over the resonant frequencies of LC resonators, especially when the driving frequency is fixed or when multiple resonators are involved.
Innovation Solution
The implementation of active variable reactance systems, which use electrically-controllable switching devices to adjust the duty cycle of the switch, allowing for continuous tuning of the resonant frequency of LC resonators without the need for electromechanical devices or non-linear reactances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resonators with higher quality factor are used, then wireless power transfer efficiency is improved, but the resonant response curve becomes narrower requiring more precise frequency control
Solution Approach 1:
The patent implements dynamically tunable resonators where the resonant frequency can be adjusted in real-time to match the driving frequency. This is achieved through variable reactance elements that allow the resonant frequency to adapt, resolving the contradiction by making the system flexible rather than fixed, thus maintaining high efficiency without requiring extremely precise fixed frequency control
Solution Approach 2:
The patent changes the resonant frequency parameter of the resonators to match the fixed driving frequency. By adjusting the resonant frequency parameter dynamically rather than relying on fixed high-Q resonators, the system achieves high power transfer efficiency while accommodating less stringent frequency control requirements
2Ease of operation
If electromechanical devices or non-linear reactances are used for frequency tuning, then resonant frequency control is achieved, but device complexity and cost increase
Solution Approach 1:
The patent replaces electromechanical tuning devices with electronically controlled variable reactance elements. This substitution eliminates mechanical moving parts while achieving the same frequency tuning function, thereby reducing device complexity and improving reliability without sacrificing frequency control capability
Solution Approach 2:
The patent uses linear reactance elements controlled by switching devices to change the resonant frequency parameter. This approach avoids non-linear reactances and complex electromechanical mechanisms, achieving frequency control through simple electronic switching that modifies the effective reactance value
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 enables precise control over the resonant frequencies of LC resonators, improving the efficiency of wireless power transfer by allowing for continuous tuning over a wide range, even at high RF power levels, with minimal complexity and cost.
Implementation Method 1
an electrically-controllable switching element; and a switch controller sub-circuit configured to switch the electrically-controllable switching element at a frequency of a radio-frequency (RF) current or voltage passing through or across the device
Implementation Method 2
Resonant wireless power systems make use of magnetic or electric coupling between LC resonators in order to transfer electric power
Data Source
AI summary
Various embodiments for controlling a resonant frequency of a resonator are described. A system includes at least one resonant circuit and an active variable reactance circuit that controls a resonant frequency of the at least one resonant circuit. The active variable reactance circuit includes an electrically-controllable switching element and a switch controller sub-circuit configured to switch the electrically-controllable switching element at a frequency of a radio-frequency (RF) current or voltage passing through or across a device such that the RF current flowing from a first terminal to a second terminal is substantially sinusoidal.