Parallel-Tuned Amplifiers for Stable Wireless Power Transfer
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Solution Overview
Problem
Current wireless charging systems using resonant inductive technology are limited by amplifier sensitivity to changes in load impedance and coupling distances, leading to inefficiencies and potential damage due to impedance mismatches and reflections, especially in loosely coupled systems.
Innovation Solution
The implementation of a parallel tuned resonant LC network in Class D and E amplifiers, which maximizes voltage across the transmitter coil, reduces harmonics, and improves power delivery by operating in resonance, while a transformer further enhances flux linkage and stability, allowing efficient power transfer over longer distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional series resonant tuning is used in wireless charging systems, then the system can operate at resonant frequency, but the amplifier becomes sensitive to load impedance changes and coupling distance variations, causing inefficiencies and potential damage
Solution Approach 1:
The patent inverts the conventional series resonant configuration by using parallel resonant tuning. Instead of tuning the series resonant frequency of the transmitter coil and capacitor, the system tunes the parallel resonant frequency, which fundamentally changes the impedance characteristics and makes the amplifier less sensitive to load variations while maintaining power efficiency.
Solution Approach 2:
The patent changes the resonant tuning parameter from series resonant frequency to parallel resonant frequency. This parameter change transforms the system's electrical characteristics, creating a high-impedance tank circuit that naturally isolates the amplifier from load impedance variations and coupling distance changes, thereby improving both reliability and efficiency.
2Length of moving object
If the transmitter and receiver are spaced further apart for longer range charging, then wireless charging coverage is improved, but coupling distance increases causing impedance mismatches and reflections
Solution Approach 1:
By inverting from series to parallel resonant tuning, the system creates a high-impedance tank circuit that is inherently more stable against coupling distance variations. This allows the transmitter and receiver to be spaced further apart while maintaining impedance matching stability and preventing reflections.
Solution Approach 2:
The patent employs dynamic frequency tuning capability that allows the system to adjust and maintain parallel resonant frequency despite changes in coupling distance. This dynamic adjustment ensures continuous optimal performance even when transmitter and receiver are spaced further apart for extended charging range.
3Power
If series resonant tuning is used to maximize power transfer, then power delivery is improved, but harmonic interference increases and amplifier protection is compromised
Solution Approach 1:
The patent inverts the resonant tuning approach from series to parallel configuration. This inversion maintains effective power delivery while naturally filtering harmonic interference and protecting the amplifier, as the parallel resonant circuit presents a high impedance to harmonics while maintaining optimal power transfer at the fundamental frequency.
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 enhances power efficiency, reduces harmonic interference, and protects the amplifier from damage caused by impedance variations, enabling robust and efficient wireless charging over longer ranges and varying coupling conditions.
Implementation Method 1
The load network and matching network are tuned such that the transmitter antenna is in parallel rather than series to the resonant capacitor with the load network of the amplifier also tuned at the same corresponding resonant frequency
Implementation Method 2
a transformer further enhances flux linkage and stability, allowing efficient power transfer over longer distances
Data Source
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AI summary
The disclosed technology provides a system for transmitting wireless power for charging electronic devices, e.g., smartphones, medical appliances, industrial equipment, and robotics. Some embodiments include parallel tuned resonant LC networks, load networks, and impedance matching networks for Class D and E, single-ended or differential, amplifier topologies for wireless power transfer in resonant inductive systems.