This article describes the evolution of the OCPP protocol, upgrading from version 1.5 to 2.0.1, highlighting the improvements in security, smart charging, feature extensions, and code simplification in version 2.0.1, as well as its key role in electric vehicle charging.
Table Of Contents
I.Introduction of OCPP Protocol
The full name of OCPP is Open Charge Point Protocol, which is a free and open protocol developed by OCA (Open Charge Alliance), an organization based in Netherlands. The Open Charge Point Protocol (OCPP) is a unified communication scheme between a CS and any Charging Station Management System (CSMS). This protocol architecture supports the interconnection of any charging service provider’s centralized management system with all charging stations, and is primarily designed to address the communication difficulties that arise in vendor-locked proprietary charging networks.OCPP supports the management of communication between charging stations and the centralized management system of each provider.It changes the closed nature of vendor-locked proprietary charging networks. (The official specification for OCPP 2.0.1 can be accessed via the Open Charge Alliance (OCA) website for reference.), which has caused problems for a large number of EV owners and real estate managers, and has led to a widespread call for an open model across the industry.
•Benefits of the OCPP protocol
•Open & free to use
•Prevents lock-in to a single provider (charging platform)
•Reduces integration time/effort and IT issues
1、History of OCPP
2. OCPP version introduction
As shown below, from OCPP1.5 to the latest OCPP2.0.1
Because there are too many proprietary protocols in the industry to support a unified service experience and operational interconnection between different operator services, OCA took the lead in developing the open protocol OCPP1.5. SOAP is limited by its own protocol constraints and cannot be widely and rapidly popularized.
•OCPP 1.5
communicates with central systems via SOAP protocol based on HTTP protocol to operate charging points It supports the following functions: Local and remotely initiated transactions, including metering of billing
•OCPP1.6 (SOAP/JSON)
OCPP1.6 version, joined the JSON format implementation, and increased the expansion of smart charging. The widely adopted 1.6J (JSON) version utilizes the WebSocket protocol (RFC 6455) for communication, enabling efficient bidirectional data exchange in any network environment to send each other data, the most used protocols on the market is the 1.6J version, support for websockets protocol-based JSON format data to reduce data traffic.
Supports JSON format data based on websockets protocol to reduce data traffic (JSON, JavaScript Object Representation, is a lightweight data exchange format) and allows operation on networks that do not support charging point packet routing (e.g., public internet). Smart charging: load balancing, centralized smart charging and local smart charging. Allow charging points to resend their own information (based on current charging point information), such as the last metered value or the state of the charging point.
•OCPP 2.0 (JSON)
OCPP 2.0, released in 2018, improves transaction processing, increases security, device management: adds smart charging functionality, for topologies with energy management systems (EMS), local controllers, and for EVs with integrated smart charging, charging stations and charging station management systems. Supports ISO 15118: Plug and Play and Smart Charging requirements for electric vehicles.
•OCPP 2.0.1 (JSON)
OCPP 2.0.1 is the latest version, released in 2020. It provides new features and improvements such as support for ISO15118 (Plug and Play), enhanced security and overall improved performance.
Note：The official specification for OCPP 2.0.1 can be accessed and cited via the Open Charge Alliance (OCA) website for reference. (Citation to the OCA website is recommended.)
Ⅱ.OCPP Version Compatibility
OCPP1.x is compatible with lower versions, OCPP1.6 is compatible with OCPP1.5, OCPP1.5 is compatible with OCPP1.2.
OCPP2.0.1 is not compatible with OCPP1.6, OCPP2.0.1 although some of the contents of the OCPP1.6 also have, but the data frame format has been completely different from that sent.
OCPP 2.0.1 protocol
1、Difference between OCPP 2.0.1 and OCPP 1.6
Compared with earlier versions such as OCPP 1.6, OCPP 2.0. 1 has major improvements in the following areas:
a. Improved security
OCPP2.0.1 is security hardened by introducing HTTPS connections based on Secure Sockets Layer and a new certificate management scheme to ensure the security of communications.
b.Adding New Features
OCPP2.0.1 adds many new features, including intelligent charging management, and more detailed fault reporting and analysis.
c. More Flexible Design
OCPP2.0.1 has been designed to be more flexible to meet the needs of more complex and diverse applications.
d. Code Simplification
OCPP2.0.1 simplifies the code, making it easier to implement the software.
OCPP2.0.1 firmware update added digital signature, to prevent the firmware download is incomplete, resulting in firmware update failure.
In practical application, OCPP2.0.1 protocol can be used to realize remote control of charging pile, real-time monitoring of charging status, user authentication and other functions, which greatly improves the use of charging equipment, efficiency and safety.OCPP2.0.1 details and functions than the 1.6 version of the many, the development of the difficulty has also increased.
2、OCPP2.0.1 function introduction
OCPP 2.0.1 protocol is the latest version of OCPP protocol. Compared with OCPP 1.6, OCPP 2.0.1 protocol has made a lot of improvements and optimizations. The main contents include:
•Message Delivery: OCPP 2.0.1 refines message structures and introduces new core messages (e.g., in Device Management and Security) to improve efficiency and performance. to improve efficiency and performance.
•Digital Certificates: In OCPP 2.0.1, digital certificate-based security mechanisms were introduced to provide hardened device authentication and message integrity protection. This is a significant improvement over OCPP1.6 security mechanisms.
•Data Model: OCPP 2.0.1 updates the data model to include support for new device types and features.
•Device Management: OCPP 2.0.1 provides more comprehensive device management functions, including device configuration, troubleshooting, software updates, etc.
•Component models: (Example: SetVariablesRequest): OCPP 2.0.1 introduces a flexible component model, which replaces the rigid configuration key structure of 1.6J. This helps enable more advanced features such as V2X (Vehicle-to-Everything) and V2G (Vehicle to Grid).
•Smart charging: OCPP2.0.1 adds support for smart charging, for example, charging power can be dynamically adjusted according to grid conditions or user needs.
•User Identity and Authorization: OCPP2.0.1 provides improved user identification and authorization mechanisms, supports multiple user authentication methods, and puts forward higher requirements for user data protection.
III. Key Technical Innovations of OCPP 2.0.1
1. Intelligent charging
External Energy Management System (EMS)
OCPP 2.0.1 addresses this problem by introducing a notification mechanism that notifies CSMS (Charging Station Management System) of external restrictions. Direct smart charging inputs that support energy management systems (EMS) can solve many situations:
Electric vehicles connected to charging points (by ISO 15118)
OCPP 2.0.1 supports ISO 15118 -updated protocol for EVSE-to-EV communication. ISO 15118 standard plug-and-play charging and smart charging (including inputs from EVs) are easier to implement using OCPP 2.0.1. Enable charging station operators to send messages (from CSMS) about charging stations for display to EV drivers.
Smart charging uses:
(1) Load Balancer
Load Balancer is mainly aimed at the internal load of the charging station. The charging station will control the charging power of each charging post according to the pre-configuration. The charging station will be configured with a fixed limit value, such as the maximum output current. In addition, the configuration can include optional options for optimizing power distribution. For instance, the limit value may be based on the local energy tariffs or real-time grid conditions, requiring the CSMS to use the Clear Charging Profile command when the limit is exceeded.
(2) Central intelligent charging
Central smart charging assumes that charging limits are controlled by a central system, which calculates part or all of the charging schedule after receiving the grid operator’s prediction information about the grid capacity, and the central system will impose charging limits on charging stations and set charging limits by responding to messages.
(3) Local intelligent charging
Local intelligent charging is realized by a local controller, which is equivalent to an agent of the OCPP protocol, responsible for receiving messages from the central system and controlling the charging behavior of other charging stations in the group. The controller itself can be equipped with charging stations or not. In the mode of local intelligent charging, the local controller limits the charging power of the charging station. During charging, the limit value can be modified. The limit value of the charging group can be configured locally or by the central system.
2. System Introduction
systematic framework
software architecture
The functional modules in OCPP2.0.1 protocol mainly include Data Transfer module, Authorization module, Security module, Transactions module, Meter Values module, Cost module, Reservation module, Smart Charging module, Diagnostics module, Firmware Management module and Display Message module
IV. Future development of OCPP
1. Advantages of OCPP
OCPP is a free and open protocol, and is also an effective way to solve the current charging pile interconnection, and has been popularized and used in many countries around the world, the future interconnection between the operator’s services will have a language to communicate.
Before the advent of OCPP, each charging post manufacturer developed its own proprietary protocol for back-end connectivity, thus locking charging post operators to a single charging post manufacturer. Now, with virtually all hardware manufacturers supporting OCPP, charging post operators are free to choose hardware from any vendor, making the market more competitive.
The same is true for property/business owners; when they purchase a non-OCPP charging station or contract with a non-OCPP CPO, they are locked into a specific charging station and charging post operator. But with OCPP-compliant charging hardware, homeowners can remain independent of their providers. Owners are free to choose a more competitive, better priced, or better functioning CPO. also, they can expand their network by mixing different charging post hardware without having to dismantle existing installations.
Of course, the main benefit of EVs is that EV drivers do not need to rely on a single charging post operator or EV supplier. As with purchased OCPP charging stations, EV drivers can switch to better CPOs/EMPs. a second, but very important benefit is the ability to use e-mobility roaming.
2, OCPP in the role of electric vehicle charging
(1) OCPP helps EVSE and CSMS communicate with each other
(2) Authorization of electric vehicle users to start charging
(3) Remote modification of charging configuration, remote charging control (start/stop), remote unlocking gun (connector id)
(4) Real-time status of charging station (available, stopped, suspended, unauthorized EV/EVSE), real-time charging data, real-time power consumption, real-time EVSE failure
(5) Smart charging (reducing grid load)
(6) Firmware Management (Over The Air update, OTA)
Linkpower was founded in 2018, with more than 8 years aiming to provide turnkey research and development... We have extensive empirical experience: Both AC and DC fast charger with OCPP1.6 software have already finished testing with more than 100 OCPP platform suppliers. We leveraged this experience to update OCPP 1.6J to 2.0.1. The commercial EVSE solution is equipped with IEC/ISO15118 modules, which is a solid step towards V2G bi-directional charging. (Download Our Detailed Case Study: Linkpower's Seamless Migration from 1.6J to 2.0.1 on Multi-Platform Testing
Post time: Oct-21-2024