Wireless Power Transmission Resonant Frequency Control
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Solution Overview
Problem
Existing wireless power transmission systems face inefficiencies when transmitting both large and small amounts of power, particularly in maintaining constant voltage operations, as they struggle to optimize power transfer efficiency across varying power levels.
Innovation Solution
A wireless electric power transmission system utilizing resonant magnetic coupling with a series and parallel resonant circuit configuration, where the resonant frequency ratio and transmission frequency are adjusted based on the coupling coefficient to minimize efficiency dips and maintain high efficiency across different power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional electromagnetic induction technology or resonant coupling systems are used for wireless power transmission, then power can be transmitted wirelessly, but transmission efficiency deteriorates when transmitting both large and small amounts of power during constant voltage operations
Solution Approach 1:
The patent applies dynamics by making the resonant frequency adjustable rather than fixed. The system dynamically changes the resonant frequency of the resonant circuit based on the coupling coefficient between coils, allowing optimal performance across varying power transmission levels and distances, thereby resolving the efficiency deterioration problem at different power levels.
Solution Approach 2:
The patent changes the resonant frequency parameter of the resonant circuit based on the coupling coefficient. By adjusting this parameter according to the actual transmission conditions (coupling coefficient), the system maintains high transmission efficiency whether transmitting large or small amounts of power, solving the adaptability problem.
2Loss of energy
If the resonant frequency is fixed in wireless power transmission systems, then the system structure is simplified, but transmission efficiency deteriorates when transmission distance or load conditions vary
Solution Approach 1:
The patent implements feedback by measuring the coupling coefficient between the transmitting and receiving coils, then using this information to adjust the resonant frequency of the resonant circuit. This closed-loop control ensures optimal transmission efficiency is maintained despite variations in transmission distance or load conditions.
Solution Approach 2:
The system transitions from a static fixed frequency design to a dynamic adjustable frequency design. The resonant frequency is dynamically modified based on real-time coupling coefficient measurements, allowing the system to adapt to changing transmission conditions while maintaining efficiency.
3Adaptability or versatility
If constant voltage operation is implemented in wireless power transmission, then compatibility with conventional devices is improved, but transmission efficiency deteriorates across varying power levels
Solution Approach 1:
The patent changes the resonant frequency parameter in response to varying power levels while maintaining constant voltage operation. This allows the system to be compatible with conventional constant voltage devices while simultaneously optimizing transmission efficiency at each power level through frequency adjustment based on the coupling coefficient.
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
The system achieves high transmission efficiency by dynamically adjusting the resonant frequency ratio and transmission frequency, ensuring efficient power transfer regardless of the power level, including during constant voltage operations, by employing a transmission frequency control mechanism that optimizes coupling and reduces efficiency dips.
Implementation Method 1
a noncontact electric power transmission system having a power transmitter circuit section and a power receiver circuit section which are adapted to be coupled to transmit electric power from a transmitter coil provided in the power transmitter circuit section to a receiver coil provided in the power receiver circuit section, in a noncontact manner by means of electromagnetic induction
Implementation Method 2
an LC series resonant circuit including a capacitor connected in series to the transmitter coil or an LC parallel resonant circuit including a capacitor connected in parallel to the transmitter coil; and an LC parallel resonant circuit including a capacitor connected in parallel to the receiver coil, wherein an oscillating frequency (Fosc) of the control IC, a resonant frequency (Fpr) of the LC series resonant circuit or the LC parallel resonant circuit in the power transmitter circuit section, and a resonant frequency (Fsr) of the LC parallel resonant circuit in the power receiver circuit section
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A wireless electric power transmission apparatus as an embodiment of the present invention includes: two antennas having the ability to transmit electric power by a non-contact method via resonant magnetic coupling, one of the two antennas being a series resonant circuit, of which the resonant frequency is fs, the other antenna being a parallel resonant circuit, of which the resonant frequency is fp; an oscillator which is connected to one of the two antennas that transmits RF power; and a control section which controls a transmission frequency according to the magnitude of the electric power to be transmitted from one of the two antennas to the other. fs/fp is set to be a value that is less than one.