Miniaturized Wireless Power Inverter Layout for Lower EMI
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Solution Overview
Problem
Existing wireless power transmitters face challenges in minimizing electromagnetic interference (EMI) while maintaining efficiency, particularly due to the presence of parallel capacitors which can hinder the use of EMI shields and complicate the miniaturization of inverter systems.
Innovation Solution
The implementation of a wireless power transmitter design that omits the parallel capacitor by incorporating a feeding coil or transformer between the transistor and the resonator, allowing for reduced EMI without compromising the functionality of the series LC resonant circuit, thereby enabling miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a parallel capacitor is used in the LCC network to improve inverter efficiency, then electromagnetic interference occurs and EMI shields cannot be effectively applied
Solution Approach 1:
The patent removes the parallel capacitor from the LCC network, extracting the source of EMI while maintaining the essential matching function through an alternative circuit configuration that eliminates the need for EMI shielding
Solution Approach 2:
The patent introduces an intermediary circuit configuration that replaces the problematic parallel capacitor, serving as a mediator that maintains impedance matching without generating EMI that would require shielding
2Reliability
If a parallel capacitor is disposed adjacent to the transmission coil to maintain high Q-factor, then the inverter size increases and miniaturization becomes difficult
Solution Approach 1:
The patent extracts and removes the parallel capacitor that was causing both EMI issues and size increase, achieving miniaturization while maintaining performance through the alternative circuit configuration
Solution Approach 2:
The patent merges the functions of the parallel capacitor into the series LC resonant circuit configuration, combining multiple functions into fewer components to reduce overall inverter volume
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 design effectively reduces EMI occurrences and allows for the miniaturization of the inverter system, enhancing the overall efficiency and performance of the wireless power transmission process.
Implementation Method 1
At least a part of the transmission coil may be magnetically coupled with the feeding coil
Implementation Method 2
a first LC resonant circuit coupled to the transistor in parallel and including a first inductor and a second capacitor coupled to the first inductor in series
Data Source
AI summary
An example wireless power transmitter may include a transistor configured to output an amplified signal, a first capacitor coupled to the transistor in parallel, a first LC resonant circuit coupled to the transistor in parallel, a third capacitor having a first end coupled to an output terminal of the transistor and the first LC resonant circuit, a feeding coil coupled to a second end of the third capacitor in series, and having at least a part configured to form a second LC resonant circuit with the third capacitor, and a transmission resonator including a transmission coil and a fourth capacitor coupled to the transmission coil in series. At least a part of the transmission coil may be magnetically coupled with the feeding coil, and at least a part of power received from the feeding coil may be output to an outside through the transmission resonator.