Adaptive Power Receiver Q-Control for Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer systems face inefficiencies due to operating conditions and mutual inductance, which can be affected by the distance between the primary and secondary units, leading to increased costs and reduced efficiency when additional coils are used to enhance coupling.
Innovation Solution
The implementation of an adaptive power receiver that uses Q-control to vary the energize and discharge durations of the power receiving cycle, allowing for impedance adjustment and communication with the wireless power transmitter through backscatter modulation, thereby optimizing power transfer and reducing the need for additional coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If additional coils are used to enhance coupling between primary and secondary units, then power transfer efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the resonant frequency of the power receiver to match the operating frequency of the power transmitter. This frequency synchronization optimizes the coupling between the single coil in the primary unit and the single coil in the secondary unit, achieving high power transfer efficiency without requiring additional coils. The controller modifies operational parameters (frequency, Q-factor) to maximize mutual inductance and minimize energy loss.
2Loss of energy
If distance between primary and secondary units is minimized, then mutual inductance increases and power transfer efficiency improves, but operating flexibility and adaptability decrease
Solution Approach 1:
The patent implements dynamics by enabling real-time adjustment of the power receiver's resonant frequency and Q-factor based on the coupling condition and distance between units. When distance increases and coupling weakens, the system dynamically tunes the resonant frequency to maintain resonance and adjusts Q-factor to optimize the balance between energy storage and dissipation. This dynamic adaptation allows efficient power transfer across a wide range of distances without requiring physical repositioning.
Solution Approach 2:
The system employs feedback mechanisms where the controller continuously monitors power transfer efficiency, coupling coefficient, and operational parameters. Based on this feedback, the controller automatically adjusts the resonant frequency and Q-factor of the power receiver to maintain optimal performance. This closed-loop control enables the system to adapt to changing distances and coupling conditions, preserving efficiency across varying operating ranges.
3Loss of energy
If Q-factor of power receiver is increased to improve resonant condition, then power transfer efficiency improves, but bandwidth and adaptability to frequency variations decrease
Solution Approach 1:
The patent applies dynamics by making the Q-factor adjustable rather than fixed. The controller dynamically modifies the Q-factor of the power receiver based on the coupling condition and frequency match between transmitter and receiver. When coupling is strong and frequency alignment is good, the system increases Q-factor to minimize energy loss. When coupling weakens or frequency drift occurs, the system reduces Q-factor to broaden bandwidth and maintain adaptability, thus optimizing the trade-off between efficiency and frequency tolerance.
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 flexible and efficient power transfer over a wide range of coupling conditions, reducing costs and maintaining high efficiency by dynamically controlling power delivery and communication without the need for additional coils, thus enhancing the overall performance of wireless power transfer systems.
Implementation Method 1
Wireless power transfer may be achieved using inductors, which produce magnetic fields when current flows through them. Conversely, current may be induced in an inductor when in the presence of a magnetic field, such as the magnetic field produced by another inductor.
Implementation Method 2
the resonating coil receives power inductively from the primary coil, magnifies the oscillations, and generates an electromagnetic field to communicate the power to the secondary unit
Data Source
AI summary
A remote device in accordance with the present invention includes an adaptive power receiver that receives wireless power from the wireless power supply by induction. The adaptive power receiver may be switched among two or more modes of operation, including, for example, a high-Q mode and a low-Q mode. By controlling the duty cycle of the switching between modes, the amount of energy received by the adaptive receiver may be controlled to communicate to the wireless power supply. This control is a form of adaptive resonance communication or Q control communication. Distortion can be reduced or eliminated by ramping between duty cycles with adjustment to intermediate duty cycle values.