Wireless Power Transfer Coil With Eddy Current Mirror Conductor
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Solution Overview
Problem
Conventional near field wireless power transmission systems experience a rapid decrease in energy transfer efficiency with increasing distance due to the third-power dependence of the magnetic field strength on distance, limiting their practical range to short distances.
Innovation Solution
Incorporating an eddy current mirror conductor positioned parallel to the transmission coil to enhance the magnetic field intensity in a specific region, thereby increasing the power transfer efficiency to inductively coupled receiving circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional near field WPT transmitter is used, then power transfer is achieved, but power transfer efficiency decreases rapidly with distance
Solution Approach 1:
An eddy current mirror conductor is introduced as an intermediary component between the transmission coil and the receiving circuit. This mirror conductor generates an enhanced magnetic field through eddy currents induced by the transmission coil, creating a magnetic enhancement region that extends the effective transmission distance while maintaining power transfer efficiency. The mirror conductor acts as a field amplifier, allowing energy transfer over distances beyond the conventional near field range.
2Length of stationary object
If transmission distance is increased, then extended range is achieved, but magnetic field strength decreases with third power of distance
Solution Approach 1:
The system changes the magnetic field distribution parameters by introducing the eddy current mirror conductor. This conductor modifies the field strength parameter through induced eddy currents, creating a localized enhancement region where the magnetic field strength is significantly increased at distances beyond the conventional near field range, effectively counteracting the third-power distance decay.
3Loss of energy
If eddy current mirror conductor is added, then power transfer efficiency is enhanced, but device complexity increases
Solution Approach 1:
The eddy current mirror conductor is designed with uniform material properties and symmetric positioning relative to the transmission coil. This homogeneous configuration simplifies the overall system design by using a single additional component with uniform characteristics, rather than requiring complex multi-element structures. The simplicity of the mirror conductor design minimizes the increase in device complexity while achieving field enhancement.
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
Enhances power transfer efficiency by a factor of up to 1.94 times compared to conventional systems, allowing for improved energy delivery over extended distances.
Implementation Method 1
an eddy current, mirror conductor, which may be referred to simply as a mirror conductor. The eddy current mirror conductor is shaped and positioned relative to the WEPT transmission coil to focus a magnetic field generated by current in the transmission coil
Implementation Method 2
an eddy current, mirror conductor. The AC power source drives an AC current at the resonant frequency of the transmission circuit through the transmission coil to generate a time varying magnetic field
Data Source
AI summary
A wireless power transfer (WPT) transmitter comprising: a power transmission coil having an axis; a power source operable to generate a time varying current in the power transmission coil that generates a time varying magnetic B field; and an eddy current conductor shaped and positioned to generate eddy currents responsive to the time varying current in the power transmission coil that enhance the B field generated by the time varying current.