Monotonic Wireless Power Transfer via KQ Control
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Solution Overview
Problem
Wireless power transfer systems often experience non-monotonic transfer functions above the resonant frequency, leading to reduced operating ranges and power levels due to resonance peak splitting, making it difficult to achieve desired power levels within specified frequency ranges.
Innovation Solution
The system adjusts the coupling coefficient (K) and loaded quality factor (Q) of the wireless power transmitter and receiver to maintain a product less than a constant, typically between 0.8 and 1.0, ensuring a monotonic transfer function across the operating frequency range by controlling capacitance, inductance, resistance, and the distance between coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the system operates at resonant frequency to maximize power transfer, then power transfer efficiency is improved, but the transfer function becomes non-monotonic causing reduced operating range due to resonance peak splitting
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the loaded quality factor Q of the resonant circuit to control the monotonicity of the transfer function. By modifying the damping characteristics through Q-factor control, the system maintains monotonic power transfer while operating at resonant frequencies, thereby preserving both efficiency and operating range. This is achieved through active control of resistive, capacitive, or inductive parameters in the resonant circuit.
2Power
If the coupling coefficient K is increased to enhance power transfer, then power level is improved, but the transfer function becomes non-monotonic reducing control precision
Solution Approach 1:
The patent implements feedback control by continuously monitoring the transfer function characteristics and adjusting the loaded quality factor Q in response to changes in coupling coefficient K. When K increases causing non-monotonic behavior, the feedback mechanism modifies Q to restore monotonicity, ensuring precise power control is maintained throughout the operating range. This closed-loop control prevents the deterioration of power control precision that would otherwise result from increased coupling.
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 allows the wireless power transfer system to maintain monotonic behavior, ensuring efficient power transfer and control across the desired frequency range, preventing power level reduction and expanding the operating range.
Implementation Method 1
Some inductive WPTS typically operate in an allocated frequency range of several hundred kilohertz using frequency variation as a power flow control mechanism
Implementation Method 2
MR WPTS typically operate on a single resonant frequency using input voltage regulation to regulate output power
Data Source
AI summary
At least one component for a wireless power transmitter or a wireless power receiver. The at least one component includes a mechanical structure and/or circuitry configured to maintain and/or adjust a coupling coefficient K between the wireless power transmitter and the wireless power receiver, a loaded quality factor Q of the wireless power receiver, or both, such that K times Q is less than a constant.