Flexible Wireless Power Coil Resonance Control
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Solution Overview
Problem
Existing wireless electric power transmission systems face challenges in downsizing receiving coils while maintaining efficiency, as efficiency deteriorates with coil downsizing, and issues arise with coil opening and closing, such as power loss, heat generation, and unnecessary radiation.
Innovation Solution
The system includes a flexible transmitting coil and receiving coil with insulating material, a resonant capacitor, and a twisted pair cable connection, allowing the coils to change resonance frequency based on usage, reducing unnecessary radiation and power consumption when closed, and optimizing magnetic coupling when open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the receiving coil is downsized to reduce device size, then portability is improved, but power receiving efficiency deteriorates rapidly
Solution Approach 1:
The receiving coil is designed with flexibility to dynamically change its configuration between opened and closed states. When opened, the coil maintains a large effective area for efficient power reception. When closed, the coil reduces its effective area to minimize power loss while the device is not in use. This dynamic reconfiguration allows the system to adapt to different usage conditions, resolving the contradiction between device size and power receiving efficiency.
2Volume of moving object
If the transmitting coil is constructed to allow opening and closing of the coil opening, then portability is improved, but power loss and heat generation occur during nonuse
Solution Approach 1:
The transmitting coil operates in periodic cycles between opened and closed states based on usage conditions. During active use, the coil remains opened to transmit power efficiently. During nonuse periods, the coil transitions to a closed state to eliminate unnecessary current flow and power consumption. This periodic switching between operational and standby states resolves the contradiction between portability and power loss.
Solution Approach 2:
The harmful effect of unnecessary current flow and power loss during nonuse is eliminated by extracting or removing the current path through the closed coil configuration. When the transmitting coil is closed, the magnetic flux generated by the coil conductor cancels itself out, preventing unnecessary radiation and power consumption. This extraction of the harmful current flow resolves the contradiction between portability and energy loss.
3Volume of moving object
If the transmitting coil is closed to reduce size, then portability is improved, but unnecessary radio frequency magnetic field radiation occurs
Solution Approach 1:
The closed coil configuration, which initially appears to cause harmful radiation, actually converts the potential harm into a benefit. When the transmitting coil is closed, the magnetic flux generated by the coil conductor cancels itself out, reducing unnecessary radiation. The same closed configuration that reduces size also eliminates harmful electromagnetic radiation, transforming a potential problem into a solution that addresses both portability and electromagnetic compatibility.
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 configuration reduces unnecessary power consumption and heat generation, suppresses unwanted magnetic fields, and maintains high power transmission efficiency by adjusting coil resonance and coupling based on usage conditions.
Implementation Method 1
a system that wirelessly transmits electric power by using coupling between an transmitting coil in an electric power transmitting device and a receiving coil in an electric power receiving device via a magnetic field
Implementation Method 2
capacitance of the transmitting resonance capacitor is determined so that while the transmitting coil is opened, resonance of the transmitting resonant circuit occurs at the switching frequency
Implementation Method 3
The transmitting coil has a coil conductor sheathed in an insulating material and has flexibility to allow a coil opening to be closed
Data Source
AI summary
An electric power transmitting device includes a radio frequency power circuit that converts a direct current power supply to radio frequency electric power having a switching frequency, a transmitting coil connected to the radio frequency power circuit and magnetically coupled to a receiving coil in an electric power receiving device, and a transmitting resonance capacitor that is connected to the transmitting coil and that forms a resonant circuit together with the transmitting coil. The transmitting coil has flexibility to allow a coil opening to be closed, and capacitance of the transmitting resonance capacitor is determined so that while the transmitting coil is opened, resonance of the resonant circuit occurs at a resonant frequency, which matches the switching frequency, and while the transmitting coil is substantially closed, the resonance of the resonant circuit does not occur at the switching frequency, which deviates from a resonant frequency of the resonant circuit.