LC Network Resonance Tuning for Wireless Power Transfer
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Solution Overview
Problem
Inductively coupled systems, such as RFID and wireless charging, face challenges with high Q-factor antenna coils that are sensitive to manufacturing tolerances and environmental changes, leading to tuning errors and restricted bandwidth for communication channels.
Innovation Solution
An automatic tuning system that adjusts the resonant frequency of the LC network by switching additional capacitance in and out of the circuit, allowing for continuous variable reactance and minimizing losses, enabling frequency and phase modulation while maintaining resonance across varying excitation frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high Q antenna inductor is used in a resonant circuit, then the circulating current increases and transmitter power decreases, but the system becomes very sensitive to tuning errors due to manufacturing tolerances and environmental factors
Solution Approach 1:
The patent applies dynamics by making the resonant circuit tunable through switched capacitor banks that can dynamically adjust the resonant frequency. The system continuously monitors the resonant frequency and adjusts the capacitance to maintain resonance despite environmental changes and manufacturing tolerances, thereby reducing sensitivity to tuning errors while maintaining high Q-factor operation
Solution Approach 2:
The patent implements feedback by measuring the resonant frequency of the LC tank circuit and using this information to control the switching of capacitor banks. The system measures the frequency, compares it to the desired resonant frequency, and adjusts the capacitance accordingly to maintain optimal operation, creating a closed-loop control system that compensates for drift and tolerances
2Use of energy by moving object
If a high Q antenna coil is used, then the transmitter power decreases, but the bandwidth for communication channels is severely restricted
Solution Approach 1:
The patent makes the resonant frequency dynamically adjustable through switched capacitor banks, allowing the system to adapt its bandwidth characteristics. By changing the total capacitance in discrete steps, the system can tune the resonant frequency to optimize for different communication bandwidth requirements while maintaining efficient power transfer
Solution Approach 2:
The patent changes the electrical parameters of the resonant circuit by switching capacitor banks in and out of the circuit. This allows the resonant frequency and Q-factor to be adjusted to optimize both power efficiency and communication bandwidth for different operating conditions and modulation schemes
3Ease of operation
If continuously variable reactance techniques are used for tuning, then the system can be adjusted, but these techniques are unsuitable for operating with large signals
Solution Approach 1:
The patent segments the capacitance into discrete switched capacitor banks rather than using continuously variable reactance. Each capacitor bank can be independently switched in or out, providing discrete but adjustable capacitance values that are suitable for large signal operation while maintaining tuning capability
Solution Approach 2:
The patent implements dynamic tuning through switched capacitors that can be controlled in real-time. The system measures the resonant frequency and dynamically switches appropriate capacitor banks to achieve the desired resonant condition, providing adaptability suitable for large signal operation
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 maintains resonance and allows for efficient frequency and phase modulation, reducing sensitivity to component parameter errors and environmental changes, thereby enhancing communication bandwidth and power transfer efficiency.
Implementation Method 1
maintaining an inductive-capacitive network at resonance
Implementation Method 2
inductively coupled systems such as radio frequency identification (RFID), implanted biomedical devices or wireless charging
Data Source
AI summary
A system is described for maintaining an inductive-capacitive (LC) network at resonance while the excitation frequency may be varied between a number of discrete frequencies at desired instants controlled by a modulation input, while taking into account component parameter errors due environmental and ageing as well as manufacturing tolerances. Control of the resonance while the excitation frequency changes permits the transmission of frequency modulation (FM) or frequency shift keying (FSK) information through an inductively coupled power transfer system.