Auxiliary Resonance Section for Wireless Power Efficiency Control
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Solution Overview
Problem
Noncontact electric power feed systems using magnetic resonance face inefficiencies due to nonuniform magnetic field distribution, leading to variable transmission efficiency depending on the relative position between the primary and secondary apparatuses.
Innovation Solution
Incorporating an auxiliary resonance section with resonators having a different resonant frequency than the main resonance operation, allowing for control of transmission efficiency by adjusting the difference between these frequencies, thereby flattening the efficiency distribution across positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the internal diameter of the electric power transmission coil is increased to expand the magnetic field distribution region, then the flexibility in relative position between primary and secondary apparatus is improved, but the magnetic field distribution becomes nonuniform, causing transmission efficiency to vary depending on position
Solution Approach 1:
The invention divides the transmission coil into multiple independent coil units arranged in an array. Each coil unit can be independently controlled to generate magnetic fields. By selectively activating specific coil units based on the position of the secondary apparatus, the system maintains uniform magnetic field distribution across the entire transmission surface, thereby ensuring consistent transmission efficiency regardless of position.
Solution Approach 2:
The invention implements dynamic control of the coil array by detecting the position of the secondary apparatus and selectively activating only the necessary coil units. This dynamic adjustment ensures that magnetic fields are generated only where needed, maintaining uniform field distribution and consistent transmission efficiency while adapting to different positions of the secondary apparatus.
2Area of stationary object
If a single large-diameter coil is used to cover a wide area, then the coverage region is expanded, but the magnetic field strength becomes nonuniform with weaker fields at the center
Solution Approach 1:
The invention segments the large-diameter coil into multiple smaller coil units arranged in an array pattern. This segmentation allows each unit to generate uniform magnetic fields locally, and when all units are activated together, they collectively provide uniform magnetic field coverage across the entire large area, eliminating the nonuniformity problem of single large coils.
Solution Approach 2:
The invention merges multiple small coil units into a coordinated array system that functions as a unified large-area transmission device. By synchronously controlling all coil units to operate together, the system achieves both wide coverage area and uniform magnetic field distribution, resolving the contradiction between area and uniformity.
3Device complexity
If electromagnetic induction type is used for noncontact power supply, then the system structure is simple, but the transmission distance is limited and axis alignment is critical
Solution Approach 1:
The invention segments the transmission system into multiple independent coil units that can operate in magnetic resonance mode. This segmentation enables the system to achieve longer transmission distances and greater alignment tolerance while maintaining relatively simple individual unit structures. The modular array configuration provides versatility without excessive complexity.
Solution Approach 2:
The invention changes the operating parameters of the coil array by utilizing magnetic resonance phenomenon at specific resonant frequencies. This parameter change enables the system to achieve extended transmission distances and reduced alignment sensitivity compared to traditional electromagnetic induction, while maintaining manageable system complexity through frequency-based control.
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 ensures uniform transmission efficiency across varying positions, reducing dead bands and enhancing flexibility and stability in noncontact electric power feeding.
Implementation Method 1
noncontact electric power feed systems with use of a type called a magnetic resonance type employing an electromagnetic resonance phenomenon
Implementation Method 2
noncontact electric power feed systems with use of a type called a magnetic resonance type employing an electromagnetic resonance phenomenon
Implementation Method 3
auxiliary resonance section including one or a plurality of resonators, in which a main resonant frequency in a main resonance operation with use of the electric power transmission coil during the electric power transmission and an auxiliary resonant frequency in the resonator are different from each other
Implementation Method 4
in a typical coil formed through winding a conductive wire or the like, a magnetic force line (magnetic flux) distribution is denser with decreasing distance to a coil end, thereby allowing a magnetic field to be stronger
Data Source
AI summary
There are provided an electric power feed apparatus, an electric power feed system, and an electronic apparatus which are capable of performing transmission efficiency control corresponding to positions of apparatuses when electric power transmission is performed between the apparatuses through a magnetic field. The electric power feed apparatus includes an electric power transmission section including an electric power transmission coil for performing electric power transmission through a magnetic field and an auxiliary resonance section including one or a plurality of resonators. A main resonant frequency in a main resonance operation with use of the electric power transmission coil during the electric power transmission and an auxiliary resonant frequency in the resonator are different from each other. A relationship (corresponding characteristics) between a relative position between the electric power feed apparatus (an electric power transmission side) and the electronic apparatus (an electric power reception side) and transmission efficiency during electric power transmission is varied by adjustment of such a difference between the resonant frequencies.