Implementation of OCPP Protocol for Electric Vehicle Applications

. The ability of the software and hardware systems to interchange information is a key factor for the success of the electric vehicle industry. Standards have been developed and are in use to ensure base level interoperability of the front-end communication and signaling processes for smart charging between electric vehicles and charge stations. The Open Charge Alliance (OCA), a group of European industries, have developed an open source common back-end protocol, called Open Charge Point Protocol (OCPP), for charging stations to reduce and secure overall investment costs. OCPP intends to enable grid services based on smart charging. In this paper the authors provide a review of the functionalities OCPP offers and how it can be used in the electrical vehicle-charging infrastructure.


Introduction
For the budding EV charging market, assortment is something worth being thankful for. Rivalry drives down expenses and raise mechanical upgrades. Today, government or private charging suppliers look over a large number of charging station makers and system framework merchants. This wide decision brings up the issue of interoperability, or, as it were, the capacity of every EV accusing station to impart of a focal framework, paying little heed to the maker or IT backend seller. That is the place the Open Charge Point Protocol (OCPP) comes in.
Keep in mind when you initially purchased a mobile phone and it just worked with one transporter? You were secured to their administration bundle regardless. The Open Charge Point Protocol (OCPP) ensures that you can switch among equipment and programming suppliers without your speculation getting to be old. It's as basic as exchanging the SIM card in your telephone. The objective of OCPP is to empower a genuinely interoperable EV charging foundation -a framework that is versatile and simple to work both for EV drivers and system administrators. With the OCPP, clients can incorporate charging stations from a few merchants into a similar IT back-end framework. They can likewise choose the most fitting charging station vendor(s) and the most proper IT back-end provider freely.
OCPP was advanced by the Open Charge Alliance and has turned into an inexorably well-known convention and a true standard in excess of 50 nations and over 10,000+ charging stations. In contrast to restrictive correspondence conventions, OCPP is open and not associated with any permitting expense or prerequisite, making it simple to receive. Embraced by many charge point sellers and focal framework providers, OCPPconsistence is presently turning into an "absolute necessity have" prerequisite among speculators. They consider it to be an approach to keep their foundation merchant nonpartisan and to decrease costs.
Open Charge Alliance discharged another sort of convention called OSCP (Open Smart Charging Protocol) This convention can be utilized to impart a 24hour forecast of the neighborhood accessible ability to the Charge Spot Operator. The Service Provider will fit the charging profiles of the electrical vehicles inside the

OCPP Version History
There are mainly three different versions of OCPP from the time of its first release. They are OCPP 1.5, OCPP 1.6 and OCPP 2.0 respectively.

OCPP 1.2
This version of OCPP is similar to OCPP 1.5, with fewer functionalities.

Implementation of OCPP 2.0
The OCPP protocol describes many use cases and messages. There are 16 Functional Blocks with one or more use cases in each of them. Out of these only some are needed to implement a basic Charging Station or CSMS. Table III lists messages that are typically implemented to deliver basic functionality for an OCPP managed Charging Station.

Booting, Configuration and Resetting a Charging Station
Booting, configuring and resetting of the Charging Station Functionalities goes under the Provisioning Functional block of OCPP 2.0. This Functional Block depicts every one of the functionalities that assistance a CSO arrangement their Charging Stations, enabling them to validate certifications and recover setup data from these Charging Stations over a system. Also, it comprises of the capacity to make changes to the Charging System configuration, as well. There are 12 use cases which gone under this functional block, among

Authorization options
This functionality comes under the Authorization Functional block of OCPP 2.0, This functional block describes all the authorization-related functionalities, it contains different ways of authorizing a user (online and/or offline), the AuthorizeRequest message handling, and the Authorization Cache functionality, etc. When a user wishes to unplug the electric vehicle from the Charging Station, the Charging Station needs to verify that the user is either the one that initiated the charging or that the user is in the same group and thus allowed to terminate the charging. Once authorized, the Charging Station informs the CSMS that the charging has been stopped. This functional block has 16 Use Cases in which any one of these -EV Driver Authorization using RFID, Authorization using a start button and Authorization using PIN-code are mandatory for the basic implementation.

Sample Interface
The OCPP protocol ensures the standardized communication between the Central Management System (CSMS) and the Charging Station. A user interface will make it convenient to for the users to work with this protocol running in the back-end. Figure II shows possible user interfaces, which can be used by the CSO in the CSMS and the consumer charge the electric vehicle at the charging station.
This sample implementation of the OCPP 2.0 protocol was developed using the Java programming language. Concepts like to object oriented programming and web sockets offered by the Java language makes it easy to implement the requirements of this protocol. The frontend design uses JavaFX to generate the graphical user interface (GUI).

Conclusion
This paper reviews the Open Charge Point Protocol (OCPP), which can be adopted as a standard for the back-end communication between electric vehicle charging stations and the central management system. The various versions of the protocol were discussed along with the improvements in its functionalities and features. Sample user interfaces of the possible implementation of the OCPP protocol were also shown for the central management system and the charging station, both. Point