dc-charging-station

This repository contains glue code in order to create a fully working DC charging station.

In our case we use open-plc-utils EcoG-io/pyslac for SLAC, EcoG-io/iso15118 for the ISO15118 stack, an EVAcharge SE for powerline communication and a Kratzer Automation battery tester EA-PSB 11000-10 as a bidirectional HV power supply.

Components

The idea of this repository is to have hardware abstraction interfaces which can be implemented for different hardware. All of these interfaces (python abstract base classes) are defined in the base_classes.py file.

For implementing a charging station you need to implement the ChargingStation class as well as the HighVoltageSource class. You can then give them as parameters to the ISO15118 EVSE controller based on EcoG-io/iso15118. This controller will handle vehicle detection, iso15118 communication and high voltage source parameter setting.

Running

First connect your PC via ethernet to both the EVAcharge and the EA-PSB. In our setup both have static IP addresses configured in a /24 network. 192.168.188.100 for the EA-PSB and 192.168.188.250 for the evacharge.

Connect to the evacharge via ssh, flash the modem and run socat for forwarding the low level controls.

# ./flash-qca-temporarily.sh
# socat tcp-l:2020,reuseaddr,fork,crlf file:/dev/ttyAPP2,echo=0,b57600,raw

In a second terminal start the actual charging station code:

$ python -m venv venv
$ . venv/bin/activate
$ pip install -r requirements.txt
$ NETWORK_INTERFACE=enx7cc2c61f051e FREE_CHARGING_SERVICE=True LOG_LEVEL=INFO python3 secc-main.py

After plugging in the vehicle the charging process should start automatically.

Environment Variables

dc-charging-station

These variables control the main application logic and the selection of hardware interface implementations.

ENV	Default Value	Description
LOG_LEVEL	INFO	The logging level for the Python log service. Applies to the entire application.
NETWORK_INTERFACE	eth0	The network interface name (e.g., enx7cc2c61f051e) used for the communication.
HIGH_VOLTAGE_CONTROLLER_IMPL	mock	Specifies which implementation of the HighVoltageSource abstract base class to use.
DIN_61851_IMPL	mock	Specifies which implementation to use for the basic PWM signaling according to IEC 61851-1.
FREE_CHARGING_SERVICE	False	If set to True, the charging service is provided without requiring authorization.

pyslac (SLAC Protocol)

These variables are used to configure the SLAC (Signal Level Attenuation Characterization) process, which is managed by a pyslac adaptation.

ENV	Default Value	Description
SLAC_INIT_TIMEOUT	50	Timeout in seconds for the reception of the first SLAC message after Control Pilot state B is detected.
ATTEN_RESULTS_TIMEOUT	None	Timeout in milliseconds for the reception of all MNBC (Mid-Network Beaconing and Communication) sounds. If not set, the system uses the timeout defined by the EV.
EVSE_ID	DE*THI*H007000000	The unique identifier of the charging point.
NID	None	The 56-bit Network Identifier (NID) for the SLAC protocol, used to identify the logical network.
NMK	None	The 128-bit Network Membership Key (NMK) for the SLAC protocol, used to secure the communication on the logical network.

SECC (ISO 15118 Communication)

These variables configure the SECC (Supply Equipment Communication Controller) and the high-level communication based on the ISO 15118 standard.

ENV	Default Value	Description
SECC_ENFORCE_TLS	False	If set to True, the SECC will enforce a TLS-secured connection for all communication.
PKI_PATH	<CWD>/iso15118/shared/pki/	Path to the Public Key Infrastructure (PKI) directory containing the necessary certificates.
MESSAGE_LOG_JSON	True	Set to True to log the EXI messages as JSON. This requires the LOG_LEVEL to be set to DEBUG.
MESSAGE_LOG_EXI	False	Set to True to log the raw EXI bytestream messages. This requires the LOG_LEVEL to be set to DEBUG.
PROTOCOLS	DIN_SPEC_70121,ISO_15118_2,...	A comma-separated list of enabled communication protocols on the SECC.
AUTH_MODES	EIM,PNC	A comma-separated list of selected authentication modes for the SECC (e.g., EIM for External Identification Means, PNC for Plug and Charge).
USE_CPO_BACKEND	False	Set to True to indicate that a CPO (Charge Point Operator) backend is available to fetch certificates or authorization data.
ENABLE_TLS_1_3	False	Set to True to enable the use of TLS version 1.3 for the communication link between the SECC and the EVCC.

Hubject PKI (pki/chargebyte.py)

pki/chargebyte.py registers this charging station at the Hubject OPCP PKI and keeps the SECC leaf certificate up to date. It writes seccLeafCert.pem, cpoCertChain.pem, the CA certificates and the private key into <PKI_PATH>/iso15118_2/, i.e. exactly where the iso15118 stack looks for them.

$ HUBJECT_CLIENT_ID=... HUBJECT_CLIENT_SECRET=... EVSE_ID='DE*THI*H007000000' python3 -m pki.chargebyte

Nothing is requested as long as the stored certificate belongs to the given EVSE ID, matches the stored private key, has a complete chain and does not expire within the next HUBJECT_RENEW_BEFORE_DAYS days.

ENV	Default Value	Description
HUBJECT_CLIENT_ID	-	OAuth2 client id for the Hubject API. Required.
HUBJECT_CLIENT_SECRET	-	OAuth2 client secret for the Hubject API. Required.
HUBJECT_ENV	qa	qa or prod, selects the OPCP base URL and the OAuth audience.
HUBJECT_TOKEN_URL	https://auth.eu.plugncharge.hubject.com/oauth/token	Token endpoint, the same one for both environments.
HUBJECT_OPCP_URL	https://eu.plugncharge-qa.hubject.com	OPCP base URL, derived from HUBJECT_ENV if not set.
HUBJECT_AUDIENCE	value of HUBJECT_OPCP_URL	OAuth audience requested for the access token.
HUBJECT_EVSE_ID	derived from EVSE_ID	The EVSE ID registered at Hubject. Hubject requires the DIN SPEC 91286 notation DE*THI*E1234567, so a different type identifier (as in the default DE*THI*H007000000) is replaced by E.
SECC_COMMON_NAME	value of HUBJECT_EVSE_ID	Common name of the SECC certificate. Set this to use a SECC ID (DE-THI-S-<32 to 59 characters>) instead of the EVSE ID.
HUBJECT_ORGANIZATION	Technische Hochschule Ingolstadt	Organization name in the CSR.
HUBJECT_COUNTRY	DE	Country code in the CSR.
HUBJECT_RENEW_BEFORE_DAYS	14	Renew the certificate this many days before it expires.
HUBJECT_MANUFACTURER, HUBJECT_DEVICE_NAME, HUBJECT_DEVICE_SW_VERSION, HUBJECT_EVSE_SERIAL, HUBJECT_OCPP_VERSION	chargebyte, EVAcharge SE, 1.0, 1, 2.0.1	Device information sent to Hubject when registering the EVSE ID.
FORCE_CERTIFICATE_ENROLLMENT	False	Request a new certificate even if the stored one is still valid.

Unit Tests

This repository is using pytest to test the implementations of interfaces to various devices. In the root directory use the following to run all tests:

pytest .