Unequilateral Rectangular Transmitter Coil for EV Wireless Charging
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Solution Overview
Problem
Existing contactless energy transmission systems face challenges in achieving optimal coupling between transmitter and receiver coils while minimizing stray fields, which are essential for efficient energy transfer and safety, particularly in applications like electric vehicle charging.
Innovation Solution
The design of transmitter coils with a winding area between unequilateral rectangles, where the width difference between the outer and inner rectangles is greater than the height difference, and the use of multiple conductors connected to independent power supplies, allows for improved coupling and reduced stray fields by adjusting power transmission efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transmitter coil with uniform winding width is used, then the structure is simple and easy to manufacture, but the coupling between transmitter and receiver coils is suboptimal and stray fields are not minimized
Solution Approach 1:
The patent applies asymmetry by designing the transmitter coil with a non-uniform winding width where the ring area width varies along the perimeter. Specifically, opposite sides of the rectangular coil have different winding widths, creating an asymmetric structure that optimizes the magnetic field distribution and coupling characteristics while reducing stray fields, thereby resolving the contradiction between coupling efficiency and structural simplicity.
2Productivity
If high power transmission is used for fast charging, then charging speed is improved, but energy losses and stray field emissions increase
Solution Approach 1:
The patent applies local quality by varying the winding width at different locations around the coil perimeter. The wider winding sections are positioned to enhance coupling in specific directions, while narrower sections reduce stray field emissions and energy losses. This localized optimization of winding width allows the system to achieve high power transmission efficiency with reduced energy losses, resolving the contradiction between charging speed and energy efficiency.
3Reliability
If a larger transmitter coil area is used, then coupling with receiver coil is improved, but the stray field emission area increases and health risks increase
Solution Approach 1:
The patent uses asymmetric winding width distribution to concentrate the magnetic field generation in specific regions rather than uniformly across the entire coil area. The varying width creates zones of different magnetic field intensity, improving coupling efficiency in critical areas while minimizing stray field emission in other regions, thus reducing the overall harmful exposure area while maintaining effective coupling.
Solution Approach 2:
By implementing local quality through position-dependent winding width, the patent optimizes the magnetic field distribution so that wider windings are placed where strong coupling is needed, while narrower windings are placed where stray field reduction is prioritized. This localized control of field characteristics achieves effective coupling with minimized health risks from stray fields.
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 enhances energy transmission efficiency, particularly for large outputs, and minimizes health risks from electromagnetic fields, while allowing for flexible power adjustment and reduced losses during low-output transmissions.
Implementation Method 1
By employing a transmitter coil a magnetic field is generated, that in an oppositely arranged receiver coil generates a current
Data Source
AI summary
Transmitter coils (1, 1a . . . 1f) for contactless energy transmission systems (8) include a winding (2) with a number of turns of at least one conductor. Such winding (2) occupies ring area (3) between an outer larger unequilateral rectangle (4) and an inner smaller unequilateral rectangle (5). This ring area (3) is wider on the longer side (x1) of the outer rectangle (4) than it is on shorter side (x2). Transmitters (6) with such transmitter coils (1, 1a . . . 1f) may include a number of conductors and a number of power supplies (7, 7a, 7b) that may be switched and/or controlled independently of each other. Energy transmission systems (8) with such transmitter coils (1a . . . 1f)/such transmitters (6) as well as receiver coils (10) installed in motor vehicles (9), are also disclosed.