(R) Communication Between Plug-In Vehicles and Off-Board DC Chargers
|Publication Date:||1 April 2015|
This SAE Recommended Practice SAE J2847-2 establishes requirements and specifications for communication between Plug-in Electric Vehicle (PEV) and the DC Off-board charger. Where relevant, this document notes, but does not formally specify, interactions between the vehicle and vehicle operator.
This document applies to the off-board DC charger for conductive charging, which supplies DC current to the Rechargable Energy Storage System (RESS) of the electric vehicle through a SAE J1772™ coupler. Communications will be on the SAE J1772 Pilot line for PLC communication. The details of PowerLine Communications (PLC) are found in SAE J2931/4.
The specification supports DC energy transfer via Forward Power Flow (FPF) from source to vehicle.
SAE has published multiple documents relating to PEV and vehicle-to-grid interfaces. The various document series are listed below, with a brief explanation of each.
SAE J2836™ General Requirements and Use Cases. This document is divided into several sections. SAE J2836/1™ is for Utility/Smart Grid messaging, SAE J2836/2™ is for DC Charge Control, SAE J2836/3™ is for Reverse Energy Flow. SAE J2836/4™ is for Diagnostics. SAE J2836/5™ is for Consumer Requirements and the HAN. SAE J2836/6™ is for Wireless Charging.
SAE J2847 Functional Messaging Requirements. This document defines the functional messages required for a given function. This document is divided into several sections that correspond to SAE J2836 above. SAE J2847/1 is for Utility/Smart Grid messaging, SAE J2847/2 is for DC Charge Control, SAE J2847/3 is for Reverse Energy Flow. SAE J2847/4 is for Diagnostics. SAE J2847/5 is for Consumer Requirements. J2847/6 is for Wireless Charging.
SAE J2931 Digital Communications for PEVs. This series of documents defines the requirements to enable digital communications for PEVs. It is divided into several sections. J2931/1 describes overall requirements, J2931/4 is wired communications using PLC, J2931/5 is Telematics and J2931/6 is for Wireless Charging. J2931/7 includes the Security for each of these.
SAE J2953 Plug-In Electric Vehicle (PEV) Interoperability with Electric Vehicle Supply Equipment (EVSE). This is the series that include the requirements in J2953/1 and test procedures in SAE J2953/2, for all the previous documents, including SAE J1772's control pilot and proximity circuits and functions.
SAE J3072 Interconnection Requirements for Onboard, Utility-Interactive Inverter Systems. This document includes the requirements for onboard inverters to send/receive the grid signals for Vehicle to Grid (V2G) functions.
The summary of documents for DC Charging is then as follows:
SAE J1772™ is the PEV to EVSE systems document and includes the system and timing diagrams for DC Charging
SAE J2836/2™ starts with the Use Cases for DC Charging communications
SAE J2847/2 then transforms these Use Case requirements into the signals and messages
SAE J2931/1 is where the Protocol requirements are placed for all PEV communications
SAE J2931/4 is used for the PLC communication requirements for DC Charging since it is only a wired median
SAE J2953/1 is the Interoperability requirements
SAE J2953/2 is the Interoperability procedure and plan
SAE J2931/7 includes the security
The primary purpose of SAE J2847-2 is to provide the communication to achieve RESS charging control irrespective of RESS variations or energy storage technology.
SAE J2847-1 identifies the functional messaging for the PEV to connect to the utility or service provider and participate in available programs. This document, J2847-2, identifies the additional messages for DC energy transfer to the PEV.
The specification supports DC energy transfer via Forward Power Flow (FPF) from grid to vehicle, and DC Reverse Power Flow (RPF) from vehicle to grid is included in SAE J2847-3.1 DC Forward Power Flow is used to charge the vehicle's rechargeable energy storage system (RESS).