Wireless Power Transmitter Shielding Coil for Extended Transfer Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless power transfer systems, particularly magnetic induction systems, face limitations in range and efficiency due to the need for precise coil alignment and high coupling factors, which restrict their application scope.
Innovation Solution
The introduction of a field shielding unit comprising a shielding coil and a capacitor, positioned adjacent to the active coil, which strengthens the magnetic field while maintaining the impedance of the active coil unchanged, thereby allowing the inverter to remain untuned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If magnetic induction systems use tightly coupled coils with coupling factor above 0.5, then power transfer efficiency is improved, but the range of power transfer is limited and precise coil alignment is required
Solution Approach 1:
The patent introduces a resonant magnetic system as an intermediary approach between magnetic induction and electromagnetic systems. By using resonant coupling between transmitter and receiver inductors with capacitors, the system achieves efficient power transfer over extended ranges without requiring tight coupling or precise alignment, thus resolving the contradiction between efficiency and range
Solution Approach 2:
The patent changes the operating parameters by introducing resonance frequency matching between transmitter and receiver. By tuning the capacitors to achieve resonant conditions, the system transforms from a magnetic induction mode (requiring tight coupling) to a resonant magnetic mode that enables loose coupling and extended power transfer range while maintaining efficiency
2Length of moving object
If resonant magnetic systems use loose coupling with coupling factor below 0.5, then power transfer range is increased, but alignment issues are not fully rectified and additional capacitors are required
Solution Approach 1:
The patent designs the resonant magnetic system to perform multiple functions: the same inductor-capacitor combination serves both as the power transfer element and as the resonant tuning element. This multi-functionality reduces the need for additional components while achieving extended range and improved alignment tolerance
3Productivity
If magnetic induction systems use ferrite-based coils, then power transfer efficiency is improved, but the coils become heavy and fragile
Solution Approach 1:
The patent transitions from traditional ferrite-based magnetic materials to resonant magnetic systems that can operate with air-core or alternative material inductors. By utilizing resonant coupling principles, the system maintains power transfer efficiency while eliminating the need for heavy ferrite materials, thus reducing weight and improving durability
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 enhances the magnetic field strength and shields external components from magnetic fields, while ensuring no change in the impedance of the active coil, thus improving the efficiency and range of wireless power transfer without the need for retuning the inverter.
Implementation Method 1
Power transfer occurs due to coupling of magnetic fields between the coils or inductors of the transmitter and receiver
Implementation Method 2
The transmitter and receiver inductors may be loosely coupled, i.e. have a coupling factor below 0.5. However, in resonant magnetic systems the inductors are resonated using at least one capacitor
Implementation Method 3
Power transfer occurs due to coupling of magnetic fields between the coils or inductors of the transmitter and receiver
Data Source
AI summary
An apparatus for use in a magnetic induction wireless power transfer system comprises at least one booster coil positioned adjacent an active coil of a magnetic induction wireless power transfer system and a capacitor electrically connected to the booster coil. A capacitance of the capacitor is selected such that a current in the booster coil is approximately equal to a current in the active coil during wireless power transfer. The apparatus may comprise at least one shielding coil positioned adjacent an active coil of a magnetic induction wireless power transfer system, a capacitor electrically connected to the shielding coil, and a conductor positioned adjacent the shielding coil opposite the active coil. The conductor encompasses the shielding coil.