Digital Communications for Plug-in Electric Vehicles
This SAE Information Report SAE J2931 establishes the requirements for digital communication between Plug-In Vehicles (PEV), the Electric Vehicle Supply Equipment (EVSE) and the utility or service provider, Energy Services Interface (ESI), Advanced Metering Infrastructure (AMI) and Home Area Network (HAN).
This is the second version of this document and completes the step 2 effort that specifies the digital communication protocol stack between Plug-in Electric Vehicles (PEV) and the Electric Vehicle Supply Equipment (EVSE). The purpose of the stack outlined in Figure 1 and defined by Layers 3 to 6 of the OSI Reference Model (Figure 1) is to use the functions of Layers 1 and 2 specified in SAE J2931/4 and export the functionalities to Layer 7 as specified in SAE J2847/2 (as of August 1, 2012, revision) and SAE J2847/1 (targeting revision at the end of 2012).
Communications between the EVSE and other than PEV entities such as AMI, ESI, HAN, Utility head-end, etc. as shown in Figure 2 are outside of the scope of this document. It is presumed that a bridging device will be required to carry PEV information beyond the EVSE and may be collocated with the latter.
The effort continues however, to step 3 that allows public review for additional comments and viewpoints, while the task force also continues additional testing and early implementation. Results of the step 3 effort will then be incorporated into updates of this document and lead to a republished version.
The SAE J2931 family of documents has been organized into several “slash” subsections:
This document, SAE J2931/1, defines architecture and general requirements including association, registration, security, and HAN requirements, as well as mapping to other SAE documents.
SAE J2931/2 is under development and is proposed to define a MAC & PHY layer implementation of digital communications using FSK and the SAE J1772™ Pilot wire.
SAE J2931/3 is under development and is proposed to define a MAC & PHY layer implementation of digital communications using NB OFDM and either the SAE J1772™ Pilot wire or mains.
SAE J2931/4 defines the MAC & PHY layer implementation of digital communications using BB OFDM and either the SAE J1772™ Pilot wire or mains.
Testing and validation of the aforementioned physical layer specifications is ongoing, and it is possible that the results of said testing may preclude one or more of the proposed solutions as unable to meet the technical requirements. Reduction of the available options to a single, worldwide standard remains the long-term goal.
The document mapping of the PEV communication standards are further defined in section 4.
This SAE Technical Information Report is being updated to include information on the layers 3 to 6 of the ISO OSI 7-layer Communications stack to support DC Charging Application as specified in SAE J2847/2 over Broadband PLC defined in SAE J2931/4. The intent is that this stack will be also able to support SAE J2847/1. Application for PEV Communications with the Utilities based on SEP 2.0. This provides a more complete representation for this communication requirements document.
The main drivers for this revision are as follows:
Efforts to harmonize DIN, IEC, ISO and SAE related standards in the area of Vehicle to Grid (V2G) Communications starting with DC off-board charging.
Support of Combo Charging system based on SAE J1772™, SAE J2847/2, SAE J2931/4.
Ease of future integration and backwards compatibility of SEP2.0 or similar XML-based approach for PEV with Power Grid (Utility) Communications.
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