Variable Quality Factor Resonant Circuit for EV Charging
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Solution Overview
Problem
Existing inductive charging systems for electric vehicles face challenges in effectively transmitting energy and positioning signals while complying with international electromagnetic emission standards, particularly in ensuring exclusive use of the magnetic channel for either energy or positioning signals to prevent interference.
Innovation Solution
A resonant circuit device with a transmitting/receiving coil, coupling capacitor, and switching device is used, allowing for bidirectional magnetic energy transmission and separate frequency bands for energy and positioning signals, with the switching device capable of detuning the resonant circuit to prevent interference and ensure exclusive use of the magnetic channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the resonant circuit operates in a high-Q state for energy transmission, then energy transmission efficiency is improved, but positioning signal transmission is interfered with due to signal leakage
Solution Approach 1:
The patent applies dynamics by making the quality factor Q of the resonant circuit variable rather than fixed. The control unit dynamically adjusts the Q value based on the operational mode: setting it to a first value (higher Q) for energy transmission to maximize efficiency, and a second value (lower Q) for positioning signal transmission to prevent signal leakage and interference. This dynamic adjustment resolves the contradiction between energy efficiency and signal integrity.
Solution Approach 2:
The patent changes the parameter of the quality factor Q from a constant to a variable parameter. By switching between different Q values (first value for energy mode, second value for positioning mode), the system optimizes performance for each specific function. This parameter change allows the resonant circuit to adapt its characteristics to match the requirements of different operational modes, eliminating the trade-off between energy efficiency and positioning accuracy.
2Productivity
If the resonant circuit uses a fixed quality factor for energy transmission, then energy transmission is optimized, but the circuit cannot effectively transmit positioning signals without interference
Solution Approach 1:
The system transitions from a static quality factor to a dynamic one that can be adjusted in real-time. The control unit monitors the operational mode and adjusts the Q value accordingly, enabling the resonant circuit to maintain high productivity during energy transmission while ensuring reliability during positioning signal transmission. This dynamic adaptation eliminates the need to compromise between the two functions.
Solution Approach 2:
The resonant circuit is designed to perform multiple functions by varying its quality factor. It can operate as an high-efficiency energy transmission channel when Q is set to the first value, and as a reliable positioning signal transmission channel when Q is set to the second value. This multi-functionality, achieved through parameter variation, allows a single circuit to reliably perform both energy and positioning tasks without interference.
3Adaptability or versatility
If the system transmits both energy and positioning signals simultaneously, then overall system functionality is improved, but signal interference occurs due to resonance effects
Solution Approach 1:
The patent implements periodic action by alternating between energy transmission mode and positioning signal transmission mode rather than transmitting both simultaneously. The control unit switches the quality factor Q between its first and second values in periodic fashion, dedicating the resonant circuit to one function at a time. This time-division approach maintains system versatility while eliminating signal interference caused by simultaneous transmission.
Solution Approach 2:
The dynamic adjustment of the quality factor Q allows the system to adapt its characteristics based on the current transmission mode. When switching between energy and positioning functions, the Q value changes dynamically to optimize performance for the active mode and minimize interference. This dynamic behavior enables the system to maintain high adaptability while avoiding the harmful effects of simultaneous signal transmission.
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 enables efficient and interference-free transmission of energy and positioning signals, meeting international standards by adjusting the quality factor of the resonant circuit and using different frequency bands for each signal type, ensuring compliance and reducing signal interference.
Implementation Method 1
a transmitting/receiving coil L2 or a transmitting and receiving coil for transmitting and/or receiving magnetic energy
Implementation Method 2
the switching device S1 is designed to activate and/or disconnect a signal generator 201 and to detune a quality factor Q of the resonant circuit device 200
Data Source
AI summary
The invention relates to an inductive power transmission with a resonant circuit, the resonant circuit including a transmitting/receiving coil or a transmitting and receiving coil for transmitting and/or receiving electromagnetic energy, a coupling capacitor, a tuning capacitor, and a switching device, wherein the switching device is connected in series to the coupling capacitor and the tuning capacitor, and wherein, furthermore, the switching device is designed to activate and/or disconnect a signal generator and to modify a quality factor or to modify the resonance frequency of the resonant circuit.