OCPP v2 in eMobility

E-mobility is growing so fast that we can say, it is becoming the new mobility standard worldwide. This is possible only with an extensive infrastructure, which is equal to good coverage of Charging Stations. To advance the rollout of charging infrastructure, open communication standards play a key role. They enable two-way power flows, real-time information exchange, demand control, and eMobility services.

The Open Charge Point Protocol (OCPP) is one of the industry-supported standards for communication between a Charging Station / Electric Vehicle Supply Equipment (EVSE) and a Charging Station Management System (CSMS). It is an open standard with no cost or licensing barriers for adoption. With every next version starting from 1.2 OCPP becomes more and more advanced. Today it can be used in different architectures for different Charging Stations.

In April 2018, the Open Charge Alliance released a new version 2.0 of the OCPP. That version solves a lot of annoying problems from version 1.6 and provides a lot of new cool features ready to implement and use.

Figure 1. OCPP placement in EV charging landscape

Figure 2. Flow diagram

Agenda

• What’s new in OCPP 2.0?

• Use Cases

• OCPP server

What’s new in OCPP 2.0?

OCPP 2.0 introduces new functionalities compared to OCPP 1.6. Due to improvements and new features, OCPP 2.0 is not backward compatible with OCPP 1.6 Let’s see what that brings…​

Device Management

Device Management (Device Model) is a feature especially welcomed by CSOs who manages a network of charging stations. It provides the following features:

• Inventory reporting

• Improved error and state reporting

• Improved configuration

• Monitoring

Transactions improvements

Handling a large amount of transactions - especially in big networks consists of 100+ Charging Stations

• Messages StartTransaction, StopTransaction, MeterValue, and StatusNotification are replaced with TransactionEvent

• Data reduction - support for WebSocket Compression

Security Improvements

• Added Security profiles (3 levels) for Charging Station, CSMS authentication, and Communication Security

• Key management for Client-Side certificates

• Secure firmware updates

• Security event log

Extended Smart Charging

In OCPP 2.0 Smart Charging functionality has been extended

• Direct Smart Charging inputs from an Energy Management System (EMS) to a Charging Station

• Improved Smart Charging with a local controller

• Support for integrated smart charging of the CSMS, Charging Station, and EV ([ISO15118-1]).

Support for ISO 15118

The ISO 15118 standard [ISO15118-1] is a newer protocol for EVSE to EV communication, compared to IEC 61851 [IEC61851-1]. ISO 15118 allows a lot of new features and more secure communication between EVSE and EV. Added features supported by ISO 15118:

• Plug & Charge

• Smart Charging including input from the EV

Improvements in customer experience

• More authorization options: Plug & Charge [ISO15118-1], Payment Terminals, local mechanical key, Smartphones, etc.

• Displaying messages (transaction-related/global) on a Charging Station to be displayed to EV drivers

• EV Driver preferred languages

• Tariff and Costs: showing the applicable tariff/price before/during an EV driver starts charging on a Charging Station

OCPP-J Improvements

• Simple Message routing

• No SOAP Support

Minor changes/extensions

• Renamed messages: message names have been changed, where appropriate, to improve clarity and understanding

• TransactionId Identification & Message Sequencing: In OCPP 2.0, transaction identifiers are generated by the Charging Station

• Extended enumerations: support more use cases

• Offline Transaction Event Indication: support for transaction event occurred while the Charging Station was Offline

• Personal message: Message that can be shown to the EV Driver

Use Cases

List of use cases supported by OCPP 2.0 and which use cases were already supported by OCPP 1.6

UC ID	Use Case	OCPP 1.6	new in OCPP 2.0
A - Security
A01	Update Charging Station Password for HTTP Basic Authentication		✅
A02	Update Charging Station Certificate by request of o CSMS		✅
A03	Update Charging Station Certificate initiated by the Charging Station		✅
A04	Security Event Notification		✅
B - Provisioning
B01	Cold Boot Charging Station	✅
B02	Cold Boot Charging Station - Pending	✅
B03	Cold Boot Charging Station - Rejected	✅
B04	Offline Behavior Idle Charging Station	✅
B05	Set Variables		✅
B06	Get Variables		✅
B07	Get Base Report		✅
B08	Get Custom Report		✅
B09	Setting a new NetworkConnectionProfile		✅
B010	Migrate to new CSMS		✅
B011	Reset - Without Ongoing Transaction	✅
B012	Reset - With Ongoing Transaction	✅
C - Authorization
C01	EV Driver Authorization using RFID	✅
C02	Authorization using a start button		✅
C03	Authorization using credit/debit card		✅
C04	Authorization using PIN-code		✅
C05	Authorization for CSMS initiated transactions		✅
C06	Authorization using local id type		✅
C07	Authorization using Contract Certificates		✅
C08	Authorization at EVSE using ISO 15118 External Identification Means (EIM)		✅
C09	Authorization by GroupId	✅
C010	Store Authorization Data in the Authorization Cache	✅
C011	Clear Authorization Data in Authorization Cache	✅
C012	Start Transaction - Cached Id	✅
C013	Offline Authorization through Local Authorization List	✅
C014	Online Authorization through Local Authorization List	✅
C015	Offline Authorization of unknown Id	✅
C016	Stop Transaction with a Master Pass		✅
D - LocalAuthorizationList
D01	Send Local Authorization List	✅
D02	Get Local List Version	✅
E - Transactions
E01	Start Transaction Options		✅
E02	Start Transaction - Cable Plugin First	✅
E03	Start Transaction - IdToken First	✅
E04	Transaction started while Charging Station is offline	✅
E05	Start Transaction - Id not Accepted	✅
E06	Stop Transaction Options		✅
E07	Transaction locally stopped by IdToken	✅
E08	Transaction stopped while Charging Station is offline	✅
E09	When cable disconnected on EV-side: Stop Transaction	✅
E010	When cable disconnected on EV-side: Suspend Transaction	✅
E011	Connection Loss During Transaction	✅
E012	Inform CSMS of an Offline Occurred Transaction	✅
E013	Transaction related message not accepted by CSMS	✅
E014	Check transaction status		✅
E015	End of charging process	✅
F - RemoteControl
F01	Remote Start Transaction - Cable Plugin First	✅
F02	Remote Start Transaction - Remote Start First	✅
F03	Remote Stop Transaction	✅
F04	Remote Stop ISO 15118 charging from CSMS		✅
F05	Remotely Unlock Connector	✅
F06	Trigger Message	✅
G - Availability
G01	Status Notification	✅
G02	Heartbeat	✅
G03	Change Availability EVSE	✅
G04	Change Availability Charging Station	✅
G05	Lock Failure	✅
H - Reservation
H01	Reservation	✅
H02	Cancel Reservation	✅
H03	Use a reserved EVSE	✅
H04	Reservation Ended, not used	✅
I - Tariff and Costs
I01	Show EV Driver-specific tariff information		✅
I02	Show EV Driver running total cost during charging		✅
I03	Show EV Driver final total cost after charging		✅
I04	Show fallback tariff information		✅
I05	Show fallback total cost message		✅
I06	Update Tariff Information During Transaction		✅
J - Metering
J01	Sending Meter Values not related to a transaction	✅
J02	Sending transaction related Meter Values	✅
J03	Charging Loop with metering information exchange		✅
*K - *
K01	SetChargingProfile	✅
K02	Central Smart Charging	✅
K03	Local Smart Charging	✅
K04	Internal Load Balancing	✅
K05	Remote Start Transaction with Charging Profile	✅
K06	Offline Behavior Smart Charging During Transaction	✅
K07	Offline Behavior Smart Charging at Start of Transaction	✅
K08	Get Composite Schedule	✅
K09	Get Charging Profiles		✅
K010	Clear Charging Profile	✅
K011	Set / Update External Charging Limit With Ongoing Transaction		✅
K012	Set / Update External Charging Limit Without Ongoing Transaction		✅
K013	Reset / release external charging limit		✅
K014	External Charging Limit with Local Controller		✅
K015	Charging with load leveling based on High Level Communication		✅
K016	Optimized charging with scheduling to the CSMS		✅
K017	Renegotiating a Charging Schedule		✅
L - Firmware Management
L01	Secure Firmware Update		✅
L02	Non-Secure Firmware Update	✅
L03	Publish Firmware file on Local Controller		✅
L04	Unpublish Firmware file on Local Controller		✅
M - ISO 15118 Certificate Management
M01	Certificate Installation EV		✅
M02	Certificate Update EV		✅
M03	Retrieve list of available certificates from a Charging Station		✅
M04	Delete a specific certificate from a Charging Station		✅
M05	Install CA certificate in a Charging Station		✅
M06	Get Charging Station Certificate status		✅
N - Diagnostics
N01	Retrieve Log Information	✅
N02	Get Monitoring report		✅
N03	Set Monitoring Base		✅
N04	Set Variable Monitoring		✅
N05	Set Monitoring Level		✅
N06	Clear / Remove Monitoring		✅
N07	Alert Event		✅
N08	Periodic Event		✅
N09	Get Customer Information		✅
N010	Clear Customer Information		✅
O - Display Message
O01	Set DisplayMessage		✅
O02	Set DisplayMessage for Transaction		✅
O03	Get All DisplayMessages		✅
O04	Get Specific DisplayMessages		✅
O05	Clear a DisplayMessage		✅
O06	Replace DisplayMessage		✅
P - DataTransfer
P01	Data Transfer to the Charging Station	✅
P02	Data Transfer to the CSMS	✅

OCPP server

Now it’s time to develop an OCPP server which will support communication with Charging Point using OCPP 2.0. What does it actually mean?

Assumptions

Well, the first mandatory thing is communication via the WebSocket interface (communication via SOAP is not supported anymore). Therefore all of the stuff concerning security in the network traffic layer must be set.

The second is implementation messages compliant with standard OCPP 2.0 (transactions handling mostly).

The third: we must know, that there is no need to cover all of the use cases. Most of them aren’t mandatory to support the major process of EV charging, so we can easily select features for the MVP phase.

The fourth: we don’t need Charging Point in the first development phase. Of course, later that’s required, but now we can create a simple Charging Point Simulator to emulate charging.

Technology

For our purpose (backend OCPP server) Java 11 with Spring Boot framework was used, but you can choose other backend technology you like which allows you to create backend module and support WebSocket communication. Of course, everything is embedded in docker images including database, service, etc.

Connect with written simulator via WebSocket

Connecting to OCPP Server using a simulator and connect function

Figure 3. Connect using simulator

And the result…​

Figure 4. Connection result

Yes, it seems to work fine!

Sample of implemented Use Cases

• C01 - EV Driver Authorization using RFID / AuthorizeRequest

[
  2,
  "123456789",
  "Authorize",
  {
    "idToken": {
      "idToken": "T01",
      "type": "Central"
    }
  }
]

• E02 - Start Transaction - Cable Plugin First / StatusNotificationRequest (set connector to Occupied state)

[
  2,
  "123456789",
  "StatusNotification",
  {
    "timestamp": "2021-03-19T07:10:11",
    "connectorStatus": "Occupied",
    "evseId": 1,
    "connectorId": 1
  }
]

• E02 - Start Transaction - Cable Plugin First / TransactionEvent (Started) Connect using simulator

[
  2,
  "123456789",
  "TransactionEvent",
  {
    "eventType": "Started",
    "timestamp": "2021-03-19T07:10:11",
    "triggerReason": "CablePluggedIn",
    "seqNo": 1,
    "transactionInfo": {
      "transactionId": "324567986",
      "chargingState": "EVConnected"
    }
  }
]

• E09 - When cable disconnected on EV-side: Stop Transaction / TransactionEvent (Ended)

[
  2,
  "123456789",
  "TransactionEvent",
  {
    "eventType": "Ended",
    "timestamp": "2021-03-19T07:11:11",
    "triggerReason": "EVCommunicationLost",
    "seqNo": 3,
    "transactionInfo": {
      "transactionId": "324567986"
    },
    "idToken": {
      "idToken": "T01",
      "type": "Central"
    },
    "meterValue": [
      {
        "timestamp": "2021-03-19T07:10:11",
        "sampledValue": [
          {
            "value": "75",
            "unitOfMeasure": {
              "unit": "Wh",
              "multiplier": 3
            }
          }
        ]
      }
    ]
  }
]

• G01 - Status Notification / StatusNotificationRequest (statuses according to ConnectorStatusEnumType)

[
  2,
  "123456789",
  "StatusNotification",
  {
    "timestamp": "2021-03-19T07:20:11",
    "connectorStatus": "Available",
    "evseId": 1,
    "connectorId": 1
  }
]

And let’s see how G01 looks like in OCPP simulator (request & response)

Figure 5. UC G01 example

Nicely done! That works!