EV Wireless Charging Coil Alignment via Phase Detection

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Solution Overview

Problem

Existing wireless power transfer systems for electric vehicles face challenges in ensuring optimal alignment of inductors for efficient power transfer and safety, as incorrect alignment can lead to sub-optimal power transfer and potential hazards from electromagnetic fields, and current alignment systems add complexity and cost.

Innovation Solution

The system employs a method to detect periodic variations in transmission signals between frequencies to determine the phase of the base system induction coil signal, allowing for precise alignment of the electric vehicle induction coil, using resonant structures and feedback mechanisms to ensure efficient energy transfer while minimizing safety risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If inductive power transfer systems are used for wireless charging, then convenience and safety are improved by eliminating physical connectors, but alignment precision deteriorates making optimal coil alignment difficult

Engineering Contradiction:
Improveconvenience of wireless chargingVSAvoidcoil alignment precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The system uses feedback mechanisms where the receiver vehicle detects the phase of the transmitter coil signal and communicates alignment information back to the transmitter. This enables automatic adjustment and optimization of coil alignment without requiring manual precision positioning, resolving the contradiction between ease of operation and alignment precision.

Inventive Principle:
Principle #23Feedback

2Productivity

If alignment detection systems are added to ensure optimal coil positioning, then power transfer efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system makes the induction coils serve multiple functions: they simultaneously perform power transfer and alignment detection. By using the same coils for both purposes, the system avoids adding separate alignment detection hardware, thus improving power transfer efficiency through alignment detection while minimizing the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If phase detection methods are implemented to determine coil alignment, then alignment accuracy is improved, but cost increases due to additional components

Engineering Contradiction:
Improvealignment measurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system uses the existing coil structures and their inherent electromagnetic properties to perform alignment detection. The receiver vehicle's coil naturally responds to the transmitter's magnetic field, and this response is used to determine alignment. This self-service approach provides accurate phase detection without requiring additional expensive sensors or alignment components.

Inventive Principle:
Principle #25Self-service

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 enables efficient and safe wireless power transfer by ensuring accurate alignment of induction coils, reducing complexity and cost, and providing a convenient, reliable, and safe charging solution for electric vehicles.

Implementation Method 1

An alternating current in the primary inductor produces a fluctuating electromagnetic field. When the secondary inductor is placed in proximity to the primary inductor, the fluctuating electromagnetic field induces an electromotive force (EMF) in the secondary inductor, thereby transferring power to the secondary power receiver device.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

detecting a transmission signal in a wireless power transmission. The transmission signal includes periodic variations between a first frequency and a second frequency. determining a phase of a base system induction coil signal based on the detected transmission signal.

Methodology Applied
Scientific EffectFrequency variation detection:

Data Source

PatentEP3096972B1Systems and methods for electric vehicle induction coil alignment
Publication Date: 2019.05.29 WITRICITY CORP
  • EP3096972B1 patent drawingFigure 1
  • EP3096972B1 patent drawingFigure 2
  • EP3096972B1 patent drawingFigure 3

AI summary

Systems and methods in accordance with particular embodiments provide for alignment of an electric vehicle induction coil with a base system induction coil through a determination of the phase of a base system induction coil current signal. In certain embodiments, an electric vehicle induction coil that receives a transmission signal can be determined to be in greater alignment with a base system induction coil that transmits the transmission signal as the phases of the current signals at the base system induction coil and the electric vehicle induction coil converge. One embodiment includes a method of receiving wireless power, including detecting a transmission signal in a wireless power transmission, the transmission signal comprising periodic variations between a first frequency and a second frequency. The method further includes determining a phase of a base system induction coil signal based on the detected transmission signal.