CAN Bus Termination Detection for EV Charger Presence Status
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric vehicle charging systems face challenges in determining the presence status of an electric vehicle after the charging procedure is completed, as communication interfaces become inactive, making it difficult to assess whether the vehicle is still connected to the charger.
Innovation Solution
A detection unit is integrated into the charging system that utilizes a two-line bus, specifically a CAN bus, to detect the presence status by measuring voltage and current differences across bus terminations, allowing for the determination of the vehicle's connection status even after charging has finished.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the communication interface is deactivated after charging is complete, then energy consumption is reduced and communication reliability is improved, but the ability to detect vehicle presence is lost
Solution Approach 1:
The patent extracts the presence detection function from the communication interface by utilizing the passive electrical characteristics (bus termination resistance) of the connected vehicle. This allows presence detection to occur through the existing two-line bus infrastructure without requiring active communication or additional dedicated detection circuits, thereby maintaining communication reliability while enabling continuous presence detection.
2Difficulty of detecting and measuring
If additional detection circuits are added to the charger, then vehicle presence detection capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent makes the existing two-line bus serve multiple functions: both communication during charging and presence detection after charging. By measuring the electrical characteristics (voltage, current, or resistance) of the bus lines, the system determines whether a vehicle is connected without requiring separate detection circuits, thus avoiding increased device complexity while maintaining detection capability.
Solution Approach 2:
The connected vehicle's own bus termination resistance serves as the detection element. The vehicle's electrical characteristics passively provide the information needed for presence detection, eliminating the need for the charger to implement additional active detection components. The system uses what is already present in the connected vehicle rather than requiring the charger to provide separate detection functionality.
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 method enables the detection of an electric vehicle's presence status independently of communication protocols, allowing for efficient management of charging stations, billing, and grid optimization, as it can determine if a vehicle is connected or not, even after the charging session has ended.
Implementation Method 1
detecting a second bus termination arranged within the electric vehicle by means of a voltage measurement and/or a current measurement of the two-line bus
Data Source
AI summary
A method and system for detection of an electric vehicle via a two-line bus includes a detection unit for detecting a presence status of an electric vehicle. The electric vehicle connects to a charger having the detection unit. The detection unit includes a first output for driving a two-line bus, which connects the charger and the electric vehicle; and a first input for receiving signals from the two-line bus. An additional input detects a second bus termination arranged within the electric vehicle through a voltage measurement and/or a current measurement of the two-line bus, wherein detecting the second bus termination is an indication of the presence status of the electric vehicle.