Wireless Power Transmission System Using Electrical Coupling
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Solution Overview
Problem
Existing wireless power transmission systems face challenges in achieving high power transmission efficiency due to complex control methods and sensitivity to relative position accuracy, especially in electrical coupling methods, which complicates the reduction of apparatus size and increases electromagnetic field leakage.
Innovation Solution
A power transmission system that includes a power transmission apparatus with a high-frequency voltage generating circuit and a control unit to set the driving frequency at a center frequency minimizing voltage variation, allowing for efficient power transmission with simple control and reduced electromagnetic field leakage by optimizing the resonant frequencies of coupling electrodes and load circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic coupling method is used for wireless power transmission, then power can be transmitted through magnetic field, but high-accuracy relative position relationship is required between primary and secondary coils and it is difficult to reduce apparatus size
Solution Approach 1:
The patent replaces the magnetic coupling method with an electrical coupling method using capacitively coupled electrodes. This substitution eliminates the need for precise positional alignment and large coil structures, allowing for smaller apparatus size and more relaxed position accuracy requirements while maintaining reliable power transmission.
2Volume of stationary object
If electrical coupling method is used with conventional control, then apparatus size can be reduced, but complex control methods are required and power transmission efficiency is not optimized
Solution Approach 1:
The patent utilizes resonant oscillation of the capacitively coupled electrodes at a specific resonant frequency to enhance power transmission efficiency. By operating at resonance, the system achieves optimal coupling conditions without requiring complex control algorithms, thereby maintaining simple control while improving transmission efficiency.
Solution Approach 2:
The patent optimizes the control by adjusting the driving frequency to match the resonant frequency of the coupled electrode system. This parameter optimization simplifies the control strategy while maximizing power transmission efficiency, avoiding the need for complex adaptive control methods.
3Volume of stationary object
If electrical coupling method is used without frequency optimization, then apparatus size is reduced, but electromagnetic field leakage increases and power transmission efficiency decreases
Solution Approach 1:
The patent employs resonant oscillation at the natural frequency of the capacitively coupled electrode system to concentrate the electromagnetic energy within the coupling region. This resonant coupling minimizes electromagnetic field leakage to the surrounding environment while maintaining efficient power transmission, thus reducing harmful electromagnetic radiation.
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 increased power transmission efficiency with simplified control, suppresses voltage variation at the receiving electrode, and reduces electromagnetic field leakage by selecting the optimal driving frequency based on resonant frequencies, ensuring accurate power delivery and safety.
Implementation Method 1
a primary-side coupling electrode configured to electrically couple to a secondary-side coupling electrode
Implementation Method 2
a high-frequency voltage generating circuit configured to generate and apply a high-frequency voltage to the primary-side coupling electrode
Implementation Method 3
acquire a center frequency in a state in which electrical coupling between the primary-side coupling electrode and the secondary-side coupling electrode and the load circuit is weakened, the center frequency being a frequency at which the generated high-frequency voltage is minimized or substantially minimized with respect to variation in frequency
Data Source
AI summary
A power transmission system a power transmission apparatus, a center frequency acquiring unit, and a control unit. The power transmission apparatus includes a primary-side coupling electrode electrically configured to couple to a secondary-side coupling electrode and connected load circuit of a power receiving apparatus, a high-frequency voltage generating circuit configured to generate and apply a high-frequency voltage to the primary-side coupling electrode, and a driving power circuit that supplies driving power to the high-frequency voltage generating circuit. The center frequency acquiring unit acquires a center frequency at which a high-frequency high voltage applied to coupling electrode is minimized in a state in which a low load is applied to the secondary-side coupling electrode of the power receiving apparatus and the frequency of the generated high-frequency voltage is varied. The control unit sets a driving frequency of the high-frequency voltage generating circuit at or near the center frequency to supply power to the power receiving apparatus.