EV Charging Sequence Diagrams and State Machines

A collection of open-source UML sequence diagrams and finite-state machines for common EV charging protocols:

• SAE J1772 PWM Charging (Control Pilot)
• SAE J1772 PWM Controlled Charging with OCPP 1.6J
• ISO 15118-2 Controlled Charging with OCPP 1.6J
• ISO 15118-2 HLC Optimized Charge Scheduling with OCPP 2.0.1
• SAE J1772 EVSE Control Pilot FSM

📊 Diagram Comparison Overview

• SAE J1772 PWM Charging (Control Pilot)
  Focuses solely on the low-level, analog control pilot and proximity handshake between EVSE and EV to establish a charge session, modulate current and end a session.

• SAE J1772 PWM Controlled Charging with OCPP 1.6J
  Builds on the pure PWM sequence diagram by weaving in OCPP 1.6J messages between EVSE and CSMS for session management and grid-side coordination.

• ISO 15118-2 Controlled Charging with OCPP 1.6J
  Uses ISO 15118-2:2013 over HomePlug GreenPhy (HPGP) Powerline Communication (PLC) for EV ↔ EVSE and OCPP 1.6J for EVSE ↔ CSMS. The CSMS can push a charging profile to the EV, but there’s no bidirectional negotiation to balance driver energy needs and departure times with grid constraints—vehicles simply follow the profile provided by the Secondary Actor via the CSMS.

• ISO 15118-2 HLC Optimized Charge Scheduling with OCPP 2.0.1
  Retains the ISO 15118-2 HLC flows but upgrades to OCPP 2.0.1’s richer set of messages and adds true negotiation. EV, CSMS, and optionally a Secondary Actor exchange requirements and constraints so that the final schedule optimally meets both driver departure/energy needs and grid/operator limits.

• SAE J1772 EVSE Control Pilot FSM
  A finite-state machine view of the SAE J1772 control pilot, ideal for understanding basic pilot-voltage state transitions.

ℹ️ Acknowledgments & Attribution

The National Charging Experience Consortium, or ChargeX Consortium, is a collaborative effort between Argonne National Laboratory, Idaho National Laboratory, National Renewable Energy Laboratory, electric vehicle (EV) charging industry experts, consumer advocates, and other stakeholders.

These diagrams (and any derivatives thereof) were developed by the ChargeX Consortium, specifically Argonne National Laboratory.

If you publicly use, display, or redistribute them—or any modified versions—please include the following attribution in your documentation, presentations, or source:

“Diagram(s) based on work by Argonne National Laboratory (www.anl.gov).”

📂 Repository Structure

├── README.md
├── LICENSE
├── CONTRIBUTING.md
├── diagrams/
   ├── sequence/
   │   ├── pwm-charging/
   │   │   ├── pwm-charging.puml    # PlantUML source
   │   │   ├── pwm-charging.svg     # Rendered diagram (editable in Visio)
   │   │   ├── pwm-charging.png     # Rendered diagram
   │   │   └── README.md            # Description of the diagram
   │   ├── iso15118_2-ocpp2/
   │   │   ├── iso15118_2-ocpp2.puml
   │   │   ├── iso15118_2-ocpp2.svg
   │   │   ├── iso15118_2-ocpp2.png
   │   │   └── README.md
   │   ├── iso15118_2-ocpp16/
   │   │   ├── iso15118_2-ocpp16.puml
   │   │   ├── iso15118_2-ocpp16.svg
   │   │   ├── iso15118_2-ocpp16.png
   │   │   └── README.md
   │   └── pwm-ocpp16/
   │       ├── pwm-ocpp16.puml
   │       ├── pwm-ocpp16.svg
   │       ├── pwm-ocpp16.png
   │       └── README.md
   └── state-machine/
       ├── evse-control-pilot/
           ├── evse-control-pilot.puml
           ├── evse-control-pilot.svg
           ├── evse-control-pilot.png
           └── README.md      

🔧 Development Environment

1. Install the PlantUML extension
   • In VS Code, open the Extensions view (Ctrl+Shift+X / Cmd+Shift+X) and install PlantUML by jebbs.
2. Install prerequisites
   • Java JDK (version 8 or later) for PlantUML’s runtime.
   • Graphviz (https://graphviz.org/) to render diagrams.
3. Configure PlantUML in VS Code
   • Open Settings (Ctrl+, / Cmd+,) and search for plantuml.
   • If using a local PlantUML JAR, set plantuml.server to the file path (e.g., "/path/to/plantuml.jar") and ensure java is in your system PATH.
   • Set plantuml.exportFormat to svg (or png) as preferred.
4. Preview and export diagrams
   • Open any .puml file and press Alt+D to launch the PlantUML preview.
   • Use the export buttons in the preview toolbar to generate .svg or .png files directly.

🤝 Contributing

• Fork, add your diagram or update existing, submit a PR.
• Please follow the naming conventions in the folder structure.
• See CONTRIBUTING.md for details.

📄 License

This project is licensed under Apache 2.0. See LICENSE for details.