Variable Gap Wireless Power Transmission Circuit Tuning
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Solution Overview
Problem
Wireless battery chargers with fixed gaps are inefficient due to unpredictable air gaps between coils, caused by manufacturing tolerances and wear, which affect power transfer efficiency as the alignment and spacing between coils vary.
Innovation Solution
A method to tune a power transmission circuit by sweeping frequencies across a range and measuring current and voltage to select an optimal transmission frequency, allowing for variable air gaps between inductively coupled coils, enabling efficient power transfer across rotating and static frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed gap is used between transmission coil and receiving coil, then the resonant frequency can be set to give maximum power transfer with best efficiency, but the system cannot adapt to varying air gaps caused by manufacturing tolerances and wear
Solution Approach 1:
The patent applies dynamics by making the resonant frequency adjustable rather than fixed. The system dynamically tunes the resonant frequency of the transmission coil to match the receiving coil's frequency, allowing adaptation to varying air gaps while maintaining maximum power transfer efficiency. This is achieved through variable capacitance or inductance elements that can be adjusted during operation.
Solution Approach 2:
The patent changes the resonant frequency parameter of the transmission coil to adapt to different air gap conditions. By varying the resonant frequency within a range, the system can optimize power transfer efficiency for different gap distances, thereby resolving the contradiction between maintaining fixed optimal efficiency and adapting to variable gaps.
2Loss of energy
If the air gap between coils is reduced to improve power transfer, then efficiency increases, but manufacturing tolerances and wear make the gap unpredictable and variable
Solution Approach 1:
The patent employs feedback mechanisms to detect the actual air gap conditions and adjust the resonant frequency accordingly. By monitoring parameters such as coupling coefficient or impedance changes that indicate gap variations, the system automatically tunes the transmission coil to maintain optimal efficiency despite manufacturing tolerances and wear-induced gap changes.
Solution Approach 2:
The system dynamically adjusts its operating parameters in response to varying air gaps. Rather than relying on fixed manufacturing precision, the patent uses real-time frequency tuning to compensate for gap variations, allowing the system to maintain high efficiency across a range of gap distances that would otherwise be unacceptable in fixed-gap designs.
3Device complexity
If a fixed frequency power supply is used, then the circuit structure is simple, but the system cannot adapt to changing air gaps over time
Solution Approach 1:
The patent transforms the fixed frequency supply into a dynamically adjustable frequency source. The system incorporates frequency tuning capability that allows the power supply to vary its output frequency within a specified range, enabling adaptation to changing air gaps while adding only moderate complexity through variable capacitance or inductance elements and control circuitry.
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 simplifies the tuning of resonant circuits for wireless power and communication systems, adapting to changing air gaps and ensuring efficient power transfer across a range of distances, thus overcoming the limitations of fixed-gap systems.
Implementation Method 1
The transmission coil may be inductively coupled to a receiving coil and separated from the receiving coil by an air gap
Implementation Method 2
By knowing the fixed gap, the resonant frequency can be set to give the maximum power transfer with the best efficiency
Data Source
AI summary
Systems and methods for tuning power transmission circuits may sweep a power frequency applied to a transmission coil across a plurality of frequencies. The transmission coil may be inductively coupled to a receiving coil and separated from the receiving coil by an air gap. A current and/or voltage at the transmission coil may be measured in response to the power frequency being at each frequency of the plurality of frequencies. A transmission frequency may be selected based at least in part on the measured current and/or the measured voltage.