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Communication for Smart Charging of Plug-in Electric Vehicles Using Smart Energy Profile 2.0: SAE J2847-1
SAE J2847-1 (revised August 2019) defines the communication requirements for smart charging of plug-in electric vehicles (PEVs) using the Smart Energy Profile 2.0 (SEP2.0) protocol. This standard enables utility-controlled charging, demand response, and pricing programs while ensuring grid stability and customer convenience. It focuses on forward power flow (grid to vehicle) and references SAE J2847-3 for reverse power flow (vehicle-to-grid).
Scope and Purpose
The primary purpose of SAE J2847-1 is specifying communications needed for grid-optimized energy transfer to PEVs. It supports information flows that allow vehicle owners to voluntarily participate in utility-controlled charging programs, minimizing grid stress and reducing costs. The standard covers use cases from SAE J2836-1, including direct load control, real-time pricing (RTP), critical peak pricing (CPP), and optimized energy transfer. Implementers are encouraged to consult the SEP2.0 schema and application specification for further details.
🔍 Note: This standard explicitly covers forward power flow only. Reverse power flow (V2G) is specified in SAE J2847-3.
Technical Requirements and Use Case Mapping
SAE J2847-1 maps SEP2.0 function sets to SAE J2836-1 use cases. Each use case includes a description, client device requirements, and sequence diagrams. The following table summarizes key use cases and their objectives.
| Use Case | Description | SEP2.0 Function Sets |
|---|---|---|
| U2 Direct Load Control | Utility sends direct load control events to manage charging load. | Demand Response, Load Control |
| U3 Real Time Pricing (RTP) | Charging based on real-time price signals. | Price, Tariff, Meter |
| U4 Critical Peak Pricing (CPP) | Utility triggers critical peak events with higher prices. | Price, Tariff, Demand Response |
| U5 Optimized Energy Transfer | Charging optimized based on user preferences and grid conditions. | Energy Management, Flow Reservation |
Sequence diagrams are essential for understanding the communication flows between PEV, EVSE, utility, and Energy Management System (EMS). The standard also specifies handling of loss of communications or power, requiring defined fallback behaviors to ensure safe and reliable charging.
Implementation Considerations and Common Pitfalls
Designers should carefully implement the SEP2.0 schema for precise interoperability. Common mistakes include assuming this standard covers reverse power flow, neglecting robust fallback for communication loss, and misinterpreting pricing programs. The following design insights can help avoid these issues:
- Use Cases Mapping: Ensure explicit mapping from SAE J2836-1 use cases to SEP2.0 function sets as described in the standard.
- Sequence Diagrams: These are critical for understanding the required communication flows; rely on them for proper implementation.
- Loss of Communication: Implement defined fallback behaviors (e.g., safe charging mode) as per section 4.4.1 of the standard.
- Pricing Programs: Understand differences between CPP, RTP, and other tariff structures; each has distinct mapping requirements.
⚠️ Common Mistake: Do not assume J2847-1 covers V2G. For reverse power flow, refer to SAE J2847-3.
Frequently Asked Questions (FAQs)
Q1: How can SEP2.0 be implemented to enable smart charging while ensuring grid stability?
A1: Follow the sequence diagrams and use case mappings in SAE J2847-1. Implement loss-of-communication fallbacks and support utility demand response or price-based signals as described.
Q2: What should be done when communication is lost between the PEV and the utility?
A2: The standard requires defined fallback behaviors, such as reverting to a safe charging state or a default schedule, to prevent unsafe or unpredictable charging.
Q3: Does this standard support vehicle-to-grid (V2G) power flow?
A3: No. J2847-1 covers forward power flow only. V2G reverse power flow is specified in SAE J2847-3.
Q4: What are the key differences between CPP and RTP in SEP2.0 communication?
A4: RTP uses continuously updated real-time prices, while CPP relies on occasional critical peak events. Both require distinct function set mappings as outlined in the standard.
For further details, consult the full SAE J2847-1 document and the SEP2.0 application specification.
