WLAN Handoff Protocols for Dynamic EV Wireless Charging

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Solution Overview

Problem

The existing protocols for dynamic wireless power transfer (D-WPT) in electric vehicles lack standardized message sequencing and rules, making it difficult to perform association, pairing, and handoff processes between an electric vehicle communication controller (EVCC) and a supply equipment communication controller (SECC) using wireless local area network (WLAN) technology, especially in multiple-AP environments.

Innovation Solution

A charging communication method utilizing WLAN technology for electric vehicles, involving association, pairing, and SECC discovery protocol (SDP) between EVCC and SECC, with processes for handoff and information exchange to accommodate changes in driving situations, including alignment checks and power transfer management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dynamic wireless power transfer (D-WPT) is implemented without standardized protocols, then power transfer capability is provided, but communication reliability and system stability deteriorate due to lack of standardized message sequencing and handoff rules

Engineering Contradiction:
ImproveD-WPT service capabilityVSAvoidcommunication reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by establishing standardized message sequencing parameters and communication protocols for D-WPT systems. Specific message types, transmission sequences, and handoff rules are defined to transform the unstandardized communication into a reliable standardized process, resolving the contradiction between providing D-WPT service capability and ensuring communication reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The communication process is segmented into distinct standardized phases including association, pairing, authentication, and handoff procedures. Each phase has defined message sequences and protocols, allowing the complex D-WPT communication to be broken down into manageable, reliable segments that can be executed in a predetermined order

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If multiple access points (APs) are used for D-WPT service, then service coverage and adaptability are improved, but device complexity and communication management difficulty increase

Engineering Contradiction:
Improveservice coverageVSAvoidcommunication management complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent implements dynamic handoff mechanisms that allow the EVCC to automatically switch between multiple APs and SECCs based on real-time communication quality and positioning information. This dynamic approach enables the system to manage multiple access points efficiently by actively selecting the optimal connection, thereby expanding service coverage while maintaining manageable complexity through automated decision-making protocols

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Positioning information and communication quality metrics are continuously fed back to the EVCC and SECC, enabling real-time decisions about which AP to connect to. This feedback mechanism allows the system to dynamically adjust connections across multiple APs based on actual performance, expanding coverage area while keeping communication management complexity manageable through data-driven decisions

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If association and pairing procedures are performed without standardized protocols, then system flexibility is maintained, but communication efficiency and power transfer reliability deteriorate

Engineering Contradiction:
Improvesystem flexibilityVSAvoidcommunication efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing association, pairing, and authentication procedures before actual power transfer begins. These preparatory steps are standardized to ensure efficient communication setup, allowing the system to maintain flexibility in choosing different APs while ensuring that communication efficiency is optimized through pre-established protocols and procedures

Inventive Principle:
Principle #10Preliminary action

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 efficient dynamic wireless power transfer while a vehicle is in motion, facilitating seamless communication and power transfer between EVCC and SECC, even in multiple-AP environments, ensuring reliable charging operations.

Implementation Method 1

a reception pad of a vehicle assembly (VA) mounted in 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 EffectInductive resonance coupling: Electromagnetic Induction

Data Source

PatentEP4606633A1Wireless-LAN-based charging communication apparatus and method for dynamic wireless power transfer, and handoff method
Publication Date: 2025.08.27 HYUNDAI MOTOR CO LTD
  • EP4606633A1 patent drawingFigure 1
  • EP4606633A1 patent drawingFigure 2
  • EP4606633A1 patent drawingFigure 3

AI summary

A charging communication method according to the present disclosure may be performed by an electric vehicle communication controller (EVCC) in an electric vehicle and may include: performing an association with a supply equipment communication controller (SECC) correlated with a primary assembly transferring power to the electric vehicle based on compatibility information shared between the EVCC and the SECC; identifying the SECC providing a dynamic wireless power protocol (D-WPT) based on an SECC discovery protocol (SDP) related to the SECC; and identifying a common protocol applicable between the SECC and the EVCC.