Decoupling Wireless Charging Transmitters via Reactance Element

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Solution Overview

Problem

Existing wireless power transfer systems face inefficiencies due to mutual inductance between multiple transmitter coils, which can lead to unstable and inefficient energy transfer, especially when receivers are positioned between or far from the coils.

Innovation Solution

Incorporating a common reactance element connected to multiple driver coils to at least partially cancel mutual inductance between them, allowing for adjustable characteristics of the coils based on the receiver's position, thereby decoupling the coils and optimizing energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple transmitter coils are used to expand power delivery area, then coverage area and versatility are improved, but mutual inductance between coils causes instability and inefficiency

Engineering Contradiction:
Improvepower delivery areaVSAvoidenergy transfer stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A common reactance element is introduced as an intermediary component connected between multiple transmitter coils. This reactance element mediates the magnetic coupling between coils by providing a shared reactive path that cancels mutual inductance effects, allowing coils to operate more independently while maintaining expanded coverage area

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the electrical parameters of the transmitter coils by adding a common reactance element that modifies the overall impedance and magnetic coupling characteristics. This parameter change transforms the coils from being magnetically coupled to being effectively decoupled, improving energy transfer stability while maintaining multi-coil operation

Inventive Principle:
Principle #35Parameter changes

2Productivity

If multiple transmitter coils are used to deliver power over larger area, then scalability is improved, but mutual inductance reduces energy transfer efficiency

Engineering Contradiction:
Improvepower delivery scalabilityVSAvoidenergy transfer efficiency
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The common reactance element serves as a mediator that eliminates harmful mutual inductance between multiple transmitter coils. By providing a shared reactive compensation path, it allows the system to scale to multiple coils without suffering from energy losses due to magnetic coupling, thus maintaining high transfer efficiency across expanded power delivery areas

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If receiver position is adjusted for optimal charging, then power transfer efficiency is improved, but precise alignment requirements reduce ease of operation

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidalignment precision
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The transmitter is segmented into multiple independent coils, each capable of addressing specific receiver positions. This segmentation allows the system to maintain high efficiency by activating only the coil nearest to the receiver, eliminating the need for precise alignment while preserving energy transfer efficiency through localized power delivery

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts which transmitter coil is active based on receiver position detection. This dynamic operation allows the system to automatically optimize efficiency for any receiver position without requiring manual alignment, as the control system selects the appropriate coil to maintain optimal coupling conditions

Inventive Principle:
Principle #15Dynamics

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 solution enhances the efficiency and stability of wireless power transfer by reducing mutual inductance, allowing for scalable and flexible power delivery to multiple receivers over a larger area without the need for precise alignment.

Implementation Method 1

The reactance element is configured to at least partially cancel mutual inductance between the first driver coil and the second driver coil

Methodology Applied
Scientific EffectMutual inductance: Electromagnetic Induction

Data Source

PatentEP2891254B1Systems and methods for decoupling multiple wireless charging transmitters
Publication Date: 2019.12.18 QUALCOMM INC
  • EP2891254B1 patent drawingFigure 1~3
  • EP2891254B1 patent drawingFigure 4~5
  • EP2891254B1 patent drawingFigure 6

AI summary

This disclosure provides systems, methods and apparatus for decoupling multiple wireless charging transmitters. In one aspect, a device is configured to transmit wireless power to a first receiver. The device includes a first driver coil and a second driver coil. The device further includes a common reactance element connected to the first driver coil and the second driver coil. The reactance element is configured to at least partially cancel mutual inductance between the first driver coil and the second driver coil.