Inductive Charging Winding Segmentation for Metal Detection

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Solution Overview

Problem

Existing systems for contactless energy transmission to vehicles via inductive coupling face challenges in achieving optimal positioning and metal detection within strong magnetic fields, which affects efficient energy transfer and safety.

Innovation Solution

A system with a primary winding and a secondary winding, each composed of multiple partial windings, is used for inductive coupling, where the windings are arranged to ensure equal induced voltages and phase shifts, allowing for precise positioning and metal detection by monitoring voltage differences across the windings, even in strong fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a primary winding is used for contactless energy transmission to a vehicle, then energy can be transmitted inductively to the vehicle, but it becomes difficult to detect metal objects and achieve optimal positioning in the strong magnetic field generated

Engineering Contradiction:
Improveenergy transmission powerVSAvoidmetal detection difficulty
Core Design Contradiction:
PowerVSDifficulty of detecting and measuring

Solution Approach 1:

The primary winding is divided into multiple partial windings (first partial winding, second partial winding, etc.) that can be independently controlled. This segmentation allows the system to activate only the necessary partial windings for metal detection, reducing the overall magnetic field strength during detection while maintaining high power transmission capability when needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the primary winding are activated based on local requirements. The partial windings can be selectively energized to create localized magnetic fields for metal detection in specific areas, rather than generating a uniform strong field across the entire transmission area.

Inventive Principle:
Principle #3Local quality

2Productivity

If the vehicle is positioned quickly and accurately, then optimal coupling is achieved for efficient energy transfer, but complex positioning control is required

Engineering Contradiction:
Improvepositioning speedVSAvoidpositioning control complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system continuously monitors the magnetic coupling between primary and secondary windings by measuring parameters such as impedance changes or induced voltages. This feedback information is used to automatically adjust the vehicle's positioning, guiding it to the optimal coupling position without requiring complex manual control systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The positioning system utilizes the inherent magnetic coupling characteristics of the inductive transmission system itself to provide positioning guidance. The system self-regulates by using the coupling strength as both the objective function to optimize and the measurement signal, eliminating the need for separate positioning sensors or complex control mechanisms.

Inventive Principle:
Principle #25Self-service

3Productivity

If high-voltage current is applied to the primary winding for rapid energy transmission, then energy transfer efficiency increases, but the risk of fire from metal heating increases

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoidfire risk from metal heating
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

Before applying high-voltage current for rapid energy transmission, the system performs a preliminary metal detection phase using low-power partial windings. This preliminary action identifies and flags the presence of metal objects, preventing subsequent high-power operation that could cause overheating and fire hazards.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system converts the potentially harmful strong magnetic field into a useful detection tool by using the same magnetic coupling mechanism for both metal detection and energy transmission. The magnetic field that could heat metals is first used to detect their presence through induced voltage measurements, turning a safety hazard into a detection advantage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Enables rapid, targeted positioning of vehicles and safe energy transfer by determining optimal coupling and detecting metal presence, reducing the risk of incorrect positioning and potential fires.

Implementation Method 1

an alternating current is fed into the primary winding 71, with a winding arrangement 2 being arranged in the area of the primary winding 71, each having a first and a second winding, in particular with the winding arrangement 2 arranged in the middle of the primary winding 71

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the partial windings each having such a number of windings and such a wrapped area that the, in particular changing, magnetic flux of the Primary winding induced voltages of the partial windings are equal in magnitude

Methodology Applied
Scientific EffectMagnetic flux coupling: Electromagnetic Induction

Data Source

PatentEP2928044B1System for the contactless transmission of energy from a primary winding to a vehicle comprising a secondary winding that can be inductively coupled to the primary winding, method for positioning a vehicle, method for determining a direction and position control device
Publication Date: 2020.10.21 SEW EURODRIVE GMBH & CO KG
  • EP2928044B1 patent drawingFigure 1
  • EP2928044B1 patent drawingFigure 2
  • EP2928044B1 patent drawingFigure 3

AI summary

Method for positioning a vehicle in a position of optimal coupling between a primary winding (71) and a secondary winding in a system for contactless energy transmission from the primary winding (71) to a vehicle comprising the secondary winding inductively coupleable to the primary winding (71), wherein an alternating current is impressed into the primary winding (71), wherein a winding arrangement is arranged in the region of the primary winding (71) and on the vehicle, each arrangement comprising a first and a second winding, wherein the first and second windings are each composed of at least two partial windings, wherein the areas wound by the partial windings of a respective winding are exposed to a magnetic flux generated by the primary winding (71) and are spaced apart from each other, wherein the partial windings each have such a number of windings and such a wound area,that the voltages induced by the magnetic flux of the primary winding (71) in the partial windings are of equal magnitude, wherein the first winding is arranged such that it is twisted and spaced apart from the second winding such that each partial winding of the first winding is inductively coupled to each partial winding of the second winding, wherein, before reaching the optimal position, an alternating voltage is applied to the first winding (31) of the winding arrangement located in the region of the primary winding (71) and the vehicle is steered in the direction where the magnitudes of the voltages induced in the partial windings of the second winding of the winding arrangement (630) located on the vehicle are maximized, wherein the induced voltages have a phase shift of substantially 180° to the alternating voltage.