Page 1
E-Vehicle and Charging Station – It’s Better If They Get Along Right Away
Smart Testing of Conformance and Interoperability
The availability of a dense network of fast charging stations is a decisive factor for the acceptance of e-mobility. Ensuring interoperability between e-vehicles and charging stations still tends to be underestimated today, so comprehensive
tests in this area are indispensable to vehicle manufacturers. Until today, common practice has been to test vehicles
manually using as many real charging stations as possible. Considering the increasing number of different e-vehicles and
charging stations, this way of doing things is now reaching its limits. Manufacturers and suppliers can only reach their
goals more quickly and cost-effectively and with considerably greater test coverage if they use a suitable test system
that enables automated conformance tests based on international standards.
The use of DC-charging with high power is planned for the
fast charging of e-vehicles (EV) along highways and expressways. Public charging like this is incomparably more complex than charging an EV at home in your garage using a
typical wallbox where power flows through your own electricity meter. Primarily in Europe and the US, the CCS
(Combined Charging System) serves as the general standard for DC fast charging. A variety of different companies
and organizations have together brought the CharIN
(Charging Interface Initiative e.V.) to life, whose task is to
further develop the CCS and establish it as a global standard for the charging of battery-powered EVs. The different
areas of responsibility are divided among five focus groups,
to which members bring their expertise and workforce. The
Focus Group Conformance Test & Interoperability is, among
other things, responsible for creating specifications for test
hardware and software that can be used by e-vehicle and
charging station manufacturers for automated testing of
their products for CCS conformance.
From Charge Park to Global Testing Events
Using test systems that correspond to these specifications,
e-vehicle and charging station manufacturers are now able
to test their products without laborious manual testing.
Manual testing, which has been common until now, will no
longer be feasible in the future due to the increasing number of EVs and variety of different charging stations. For
100% test coverage, every EV would have to be tested with
01
Page 2
every conceivable charging station (Figure 1). Large OEMs
maintain “charge parks” with a selection of representative
charging stations for this purpose. Testing events where
respective manufacturers of e-vehicles and charging stations
converge to test their product against as many other products as possible are also held across the globe on a regular
basis. In more basic cases, events like this only concern the
ECU electronics level, but they can also involve entire vehicles
and charging stations. This takes lots of effort, incurs high
costs, and exceeds the abilities of smaller manufacturers
and suppliers in particular.
This is why the future belongs to conformance tests that
companies can easily execute at their own laboratories.
Developers test their actual product against a test system
corresponding precisely to the specifications of the CharIN
Focus Group Conformance Test & Interoperability on the
hardware and software side (Figure 2). This is the only way
the complexity of CCS can actually be handled. The CCS is
a powerful system that deals with a variety of different
charging modes for DC and AC charging and must take assorted standards into account at the same time, such as
DIN70121, ISO 15118 and IEC61851-1.
Technical Article / September 2020
Figure 2: Performing a conformance test on a real e-vehicle with a
CCS test system, in this case from Vector.
with incorrect content and the like. Errors cannot be inserted
intentionally through manual tests with real counterparts,
as only good cases are tested in general here. Message
sequences and content, charging parameters and other
marginal conditions can only be flexibly modified through
simulation using test systems.
As a longer-term goal, the CCS is striving toward convenient charging following the plug-and-charge principle.
Here, the vehicle need only be connected to the charging
station with a plug, after which all the necessary actions –
such as identification, billing, negotiating electricity rates
etc. – are carried out automatically. In the future, there will
also be product certification that documents that a vehicle
can be charged at any certified charging station. This certification is being promoted by CharIN. During the certification process, test companies and test partners will be involved and will subject the test object to all tests prescribed
by CharIN.
Figure 1: Ensuring interoperability of e-vehicles and charging
stations – now and in the future.
Stress for Charging Electronics: Inserting Errors
Using automated conformance tests, fault cases can also
be covered systematically. In this context, for example, you
have to check whether the charging electronics also exhibit
behavior specified by the standard if the counterpart does
not comply with the required timing or sends messages
Instructions for Standard-Compliant Test Systems
Testing a variety of different functions begins at development departments long before the official test date. The
documents provided by CharIN contain detailed instructions on how the hardware and software of a suitable test
system can be implemented, which functions are required
and which out of hundreds of possible tests are necessary.
Anyone who has the corresponding expertise and wants to
make the effort can develop a CharIN CCS Test System
(CCTS) (Figure 2). This being the case, there isn’t just “one
CCTS” – individual implementations can differ from one
another in many details, be it the user interface on the software side or the hardware equipment depending on the
System Under Test (SUT). The power unit permits a large
number of possible variations, for example. Using a power
unit with comparatively low charging power is sufficient for
testing communication. In practice, however, customer
requirements in this area differ significantly from one
02
Page 3
Technical Article / September 2020
Figure 3: Identical test cases can be applied on a
variety of different integration levels
another. This is why the CCTS specification intentionally
covers only the minimum requirements for a test system.
Ideally, test software and CCTS of this type are designed in
such a way that they permit tests on every integration level
of the development process (Figure 3). When developing
software on the first, lowest level, hardware is not yet involved, but the test cases can already be used to check the
embedded code for errors independently of any hardware.
At the next level it is the turn of the A or B sample of the
ECU. The communication hardware is connected, and communication via Powerline Communication (PLC), PulseWidth Modulation (PWM), etc. can be tested, but this still
occurs without the flow of energy. On the third level, the
pre-series or series is tested. The entire CCTS test setup,
including the power unit with a high voltage source, is required. When the vehicle requests power, the test system
can actually supply power, thus representing a complete
charging process. In any case, early testing pays off, as
troubleshooting becomes more expensive the later an error
is discovered.
Available Test Solution With a Large Number of Test
Cases in the Source Code
Vector is a contributor in the Focus Group Conformance
Test & Interoperability and is offering test cases for testing
conformance and ensuring interoperability with the CANoe
Test Package EV product. These test cases are fully oriented
toward the existing test specifications of the individual
protocols of the CCS standard and their amendments by
CharIN and fit seamlessly into the existing Vector test tool
chain. The new test package is based on the CANoe .SmartCharging option and the vTESTstudio test editor and includes a large number of individual tests available in the
source code.
As a modular system for HIL tests, the VT System test
hardware with the VT7870 insert card is available. The latter
is responsible for charging communication via PLC and
PWM. The test cases can be run immediately on the
VT System. Upon request, Vector can upgrade the VT System
to a full-featured CCTS with an additional power unit. The
power electronics are always designed individually for each
customer, as the requirements can differ not only in the
case of the final power level here. In one case, for example,
charging voltages up to 600 V are sufficient, whereas 1,000 V
are required in another. This puts Vector in a position to
supply all the required components from a single source.
The Vector E-Mobility Testing Solution also supports the
CharIN interface. This is an interface which makes it possible
to combine CCTS hardware and software from different
manufacturers. In this way, the Vector E-Mobility Testing
Solution can be used in conjunction with third-party hardware if this also supports the CharIN interface and provides corresponding drivers. The user is not only able to
continue using the available or preferred hardware but also
doesn’t have to buy expensive new hardware.
Easy Operation and Transparent Tool Flow
Operation and tool flow of the CANoe Test Package EV follow the Vector product philosophy and are simple and
clearly structured. The user generates a test unit with the
push of a button using the vTESTstudio test editor. This is
then loaded into CANoe, which functions as the executing
instance and controls the test hardware. At the end of each
test run, the system automatically generates a test report
(Figure 4). As the test scripts are available in the source
code, the user is not only able to comprehend exactly what
happens in each individual case but can also adapt the
tests to the existing test environment if necessary, for
example – once again with vTESTstudio. The tests to be
executed can easily be selected with a click of the mouse.
During the test run, the tester can already see in CANoe
which tests were successful, which were not passed, and
which are still to be executed.
This simple workflow is identical on all development levels
with the same tools, whether it’s for software testing, testing the ECU with the VT System or testing the finished
03
Page 4
Technical Article / September 2020
Figure 4: The workflow of CANoe Test
Package EV with the tools vTESTstudio
and CANoe from Vector.
pre-series/series in conjunction with the entire CCTS. In addition to CANoe, the vVIRTUALtarget software tool is used
to test the embedded code. Even when general vehicle
tests not related to e-mobility are carried out, the same
tools are always used and the processes are analogous,
which has a positive effect on investment costs.
Support for International Standards CCS, GB/T and
CHAdeMO
The CANoe Test Package EV will always be continuously
developed and supports all global charging standards. In
addition to the CCS, this primarily includes the Chinese
GB/T standard and the CHAdeMO standard, which originated in Japan. A corresponding test package is also in the
works for charging station manufacturers.
The modular nature of the Vector solution makes it possible
for users to assemble their desired test system customtailored to their needs and to only use those options and
charging standards they actually need. In addition to
CANoe with the smart charging option and vTESTstudio,
the CCS also requires the CANoe Ethernet option, as CCS
communication uses Ethernet protocol-based Powerline.
GB/T, on the other hand, uses the J1939 protocol for communication, for which the CANoe J1939 option is to be used.
CHAdeMO works solely with CAN and does not require any
additional options.
flexible in its adaptation to customer requirements and
also works with test hardware from other manufacturers
over the CharIN interface. Support for current standards is
continually being expanded, and existing test cases are always being updated based on availability and the publication of corresponding test specifications. While the CCS
and GB/T charging standards are already supported,
CHAdeMO will follow in a later version of the CANoe Test
Package EV.
A test package for the testing of charging stations will also
be released by Vector beginning in 2021. The procedure for
charging station tests will be largely identical to the one
described here for e-vehicles, and the same tools will be
used.
Jan Großmann
has been with Vector since 2011 and is responsible for the Vector
E-Mobility Testing Solution in the field of networks and distributed
systems.
Translation of German publication in Hanser automotive,
issue 7/2020
Conclusion and Outlook
The test solution presented here frees vehicle manufacturers
and suppliers from the time-consuming and laborious testing
of their products with real charging stations and also provides significantly more detailed test results. It’s extremely
Image rights: Vector Informatik GmbH
04
Loading...