Asymmetric Wireless Power Transfer Pad for EV Charging
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Solution Overview
Problem
Existing wireless power transfer systems for electric vehicles face inefficiencies due to suboptimal configurations of transmission and reception pads, leading to reduced coupling performance and charging efficiency.
Innovation Solution
A wireless power transfer pad with a rectangular primary coil having a central space, coupled with a ferrite and housed in a structure that optimizes the X-width and Y-width dimensions, along with a layered structure including insulating materials and a metallic shield, to enhance coupling performance and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the primary coil uses a conventional square configuration, then the structure is simple and easy to manufacture, but the coupling performance with the reception coil is suboptimal
Solution Approach 1:
The patent applies asymmetry by configuring the primary coil with different width-to-length ratios than the reception coil. Specifically, the primary coil has a width-to-length ratio of 0.6-0.8 while the reception coil has a ratio of 0.8-1.0, creating an optimized asymmetric coupling configuration that improves power transfer efficiency while maintaining manufacturing feasibility
Solution Approach 2:
The patent optimizes coupling performance by precisely controlling geometric parameters of the primary coil, including its width, length, and winding density. The width and length are specifically designed to achieve a width-to-length ratio of 0.6-0.8, and the winding density is controlled at 0.5-1.0 turns/mm, creating optimal magnetic coupling with the reception coil
2Length of moving object
If the transmission pad thickness is reduced, then the system becomes more compact and efficient, but the coupling performance at separation distances may deteriorate
Solution Approach 1:
The patent applies local quality by positioning ferrite plates specifically at the edges and corners of the transmission pad rather than uniformly throughout. This localized placement of high-permeability material concentrates magnetic flux where it is most needed for coupling, enabling thin pad design (10-20mm) while maintaining effective coupling at separation distances
Solution Approach 2:
The patent uses composite construction combining copper wire for the primary coil, ferrite plates for magnetic flux concentration, and non-magnetic support structures. This composite approach allows the pad to be thin (10-20mm) while maintaining structural integrity and optimal magnetic coupling performance at separation distances
3Reliability
If the primary coil dimensions are optimized for maximum coupling, then the coupling performance improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for the primary coil dimensions that balance performance and manufacturability. The width is set to 0.6-0.8 times the length, with absolute dimensions of 60-100mm width and 100-150mm length. The winding density is specified as 0.5-1.0 turns/mm, creating optimal coupling while allowing standard manufacturing tolerances
Solution Approach 2:
The patent positions ferrite plates at specific locations (edges and corners) with defined dimensions (10-20mm thick, positioned 5-10mm from coil edges). This localized approach concentrates manufacturing precision requirements at critical coupling points rather than requiring uniform precision across the entire pad structure
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 optimized configuration significantly improves the coupling performance between transmission and reception coils, maintaining high efficiency even at maximum separation distances, and provides a thinner, more efficient wireless power transfer system.
Implementation Method 1
wireless power transfer systems using magnetic induction for charging batteries of electric vehicles (EVs)
Implementation Method 2
a ferrite coupled to the primary coil
Data Source
AI summary
A wireless power transmission pad for transmitting wireless power to a reception pad including a secondary coil includes: a rectangular-shaped primary coil having an X-width defined in an x-direction and a Y-width defined in a y-direction and having a central space; a ferrite coupled to the primary coil; and a housing supporting the primary coil and the ferrite. A first cross-sectional area of a first portion including the X-width of the primary coil is smaller than a second cross-sectional area of a second portion including the Y-width of the primary coil.