Wireless Charging Coil Alignment via Alternating Magnetic Orientation Field
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Solution Overview
Problem
Existing wireless charging systems for electric vehicles face inefficiencies due to stray field losses, necessitating a method to accurately align transmission and receiving coils for optimal power transfer while minimizing interference from static magnetic fields.
Innovation Solution
A method involving the generation and detection of an alternating magnetic orientation field using coils, with sensor coils designed to be unaffected by static magnetic fields, allowing for precise alignment and foreign body detection through frequency-selective detection and modulation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless power transmission is used to charge vehicle batteries, then charging convenience is improved, but stray field losses increase reducing transmission efficiency
Solution Approach 1:
The system performs preliminary alignment detection using a detection coil and alternating magnetic field before initiating full power transmission. This preliminary action ensures optimal coil positioning is achieved first, minimizing stray field losses during the actual charging process while maintaining wireless charging convenience.
Solution Approach 2:
The patent replaces manual mechanical alignment with an automated electromagnetic detection system. The detection coil automatically senses the alternating magnetic field to determine relative coil positions, substituting mechanical adjustment with field-based sensing to achieve optimal alignment and reduce energy losses.
2Loss of energy
If coil alignment is optimized to reduce stray field losses, then transmission efficiency is improved, but alignment precision requirements increase
Solution Approach 1:
The detection coil acts as an intermediary between the transmission coil and the control system. It indirectly measures the magnetic field strength to infer relative coil positioning, providing a simplified measurement mechanism that achieves sufficient alignment precision without requiring complex direct measurement systems.
Solution Approach 2:
The system uses changes in magnetic field strength parameters detected by the coil to determine optimal alignment. By monitoring field strength variations and using this information to adjust coil positions, the system achieves precise alignment through parameter-based control rather than complex geometric measurements.
3Measurement precision
If detection coils are made insensitive to static magnetic fields, then detection accuracy is improved, but coil design complexity increases
Solution Approach 1:
The detection system uses periodic alternating magnetic fields instead of static fields for detection. This periodic action inherently makes the detection coil insensitive to static magnetic field interference while maintaining sensitivity to dynamic field changes, achieving detection accuracy without complex filtering mechanisms.
Solution Approach 2:
Instead of trying to make the coil completely insensitive to all magnetic fields through complex design, the system inverts the approach by using alternating fields for detection. This inversion naturally excludes static field interference while maintaining detection capability, simplifying the overall design.
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 approach enhances alignment precision, reduces interference from static magnetic fields, and enables efficient power transfer by optimizing coil positioning and power levels, while also detecting foreign bodies to prevent charging disruptions.
Implementation Method 1
electric power is transmitted from a stationary coil (called transmission charging coil from now on) to a vehicle-side coil by an alternating magnetic field
Implementation Method 2
detecting the orientation field using at least one coil provided for inductive excitation. The orientation field may be detected in a frequency-selective manner by the coil provided for inductive excitation, and ascertaining the relative position using an orientation receiving signal, which is induced by the orientation field in the at least one coil provided for inductive excitation
Data Source
AI summary
The present disclosure relates to automobiles and, more specifically, teaches methods and systems that may be used for wirelessly charging batteries used in vehicles. In one embodiment, a method for detecting a relative position between a vehicle-side receiving charging coil and a fixed transmission charging coil, may include: generating an alternating magnetic orientation field using one of the coils; detecting the orientation field using at least one coil provided for inductive excitation, wherein the orientation field is detected in a frequency-selective manner by the at least one coil; and ascertaining the relative position using an orientation receiving signal induced by the orientation field in the at least one coil.