Three-Phase Wireless Power Coil Layout for Low Ripple Charging

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Solution Overview

Problem

Existing wireless power transfer systems for electric vehicles face inefficiencies due to the design of single-phase coils, which exhibit high ripple current and are unsuitable for large-capacity power transfer, and there is a need for a coil structure that enhances power transfer efficiency and symmetry in magnetic field distribution.

Innovation Solution

A novel coil structure for three-phase wireless power transfer is proposed, comprising three phase coils arranged in a stacked configuration with angular differences of 120 degrees, where each coil element is connected to a common power source and shares a common feeding line, ensuring opposite magnetic fields in adjacent spaces to form a stable composite magnetic field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-loop coil is used for single-phase inductive wireless charging, then the structure is simple and easy to manufacture, but it exhibits high ripple current at high power levels and is not suitable for large-capacity power transfer

Engineering Contradiction:
Improvecoil structure simplicityVSAvoidpower transfer stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The single-phase coil is segmented into two separate coil elements that are arranged to surround adjacent spaces. These segmented coil elements are connected in parallel to a common power source, which divides the current and reduces ripple current while maintaining structural simplicity and manufacturability.

Inventive Principle:
Principle #1Segmentation

2Productivity

If three phase coils are arranged in a stacked configuration with 120 degree angular differences, then power transfer efficiency is enhanced and ripple current is reduced, but the device complexity increases

Engineering Contradiction:
Improvepower transfer efficiencyVSAvoidcoil arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The three phase coils are arranged in a stacked configuration with angular differences of 120 degrees, transitioning from a planar to a three-dimensional spatial arrangement. This dimensional change enables the magnetic fields to reinforce rather than cancel each other, enhancing power transfer efficiency while maintaining phase symmetry.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If coil elements are arranged to surround adjacent spaces with opposite magnetic fields, then a stable composite magnetic field is formed, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvemagnetic field stabilityVSAvoidcoil element positioning accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The coil elements are arranged to generate opposite magnetic fields in adjacent spaces, creating an asymmetric magnetic field distribution that ultimately forms a stable composite magnetic field. This asymmetric arrangement is designed to balance the overall magnetic field, reducing the need for high manufacturing precision while maintaining field stability.

Inventive Principle:
Principle #4Asymmetry

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

The proposed coil structure achieves low ripple current and enhanced power transfer efficiency, enabling efficient large-capacity power transfer by maintaining consistent magnetic field distribution and optimizing the coil arrangement.

Implementation Method 1

a reception pad of a vehicle assembly (VA) mounted on the electric vehicle may form an inductive resonance coupling with a transmission pad of a ground assembly (GA) installed at a charging station or a charging spot and may charge the battery of the EV using electric power transferred from the ground assembly through the inductive resonance coupling

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a typical configuration of the transmission pad or the reception pad including a ferrite structure facilitating the wireless power transfer and a coil wound around the ferrite structure

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP4576495A1Coil structure for transmitting three-phase wireless power, and wireless power transmission device and method using coil structure
Publication Date: 2025.06.25 HYUNDAI MOTOR CO LTD
  • EP4576495A1 patent drawingFigure 1
  • EP4576495A1 patent drawingFigure 2
  • EP4576495A1 patent drawingFigure 3~4

AI summary

A coil structure for transmitting three-phase wireless power is disclosed. The coil structure includes: a first coil element which corresponds to a first phase and which is arranged to surround a first area; and a second coil element which corresponds to the first phase and which is arranged to surround a second area adjacent to the first area. The first coil element and the second coil element are connected to the same power source, and the first coil element and the second coil element are branched from a branch point such that the first coil element is arranged to surround the first area and the second coil element is arranged to surround the second area.