8 electrification
Taking high-voltage system integration,
charging and safety testing of electric
vehicles to the next level
BEV (Battery Electrical Vehicle) development requires adaptations to
both the development process and its environment. While the testing of
physical components for the combustion engine has been fundamental
for the development of conventional and hybrid vehicles, the demands
for a BEV are different. Adapting to these demands presents OEMs with
a new set of challenges.
But with new challenges come new opportunities. In shifting to BEV development,
the opportunity arises to question and adapt the conventional
testing environments such as the powertrain testbed to the specific needs
of the battery electric vehicle.
In a conventional or hybrid vehicle, calibrating the powertrain requires a
lot of effort. The combustion engine interacts heavily with the transmission,
the exhaust aftertreatment system and other systems, and therefore all must
be present for the final OBD, driveability and emission calibration. On the
powertrain testbed all of these and other relevant systems are present, and
together with the high level of automation that is possible, it makes the testbed
a powerful and valuable tool.
In a BEV, however, the powertrain can be largely calibrated and optimized
at the component level, as there are fewer complex interactions to investigate
and no pollutant emissions to consider.
The calibration of the inverter
is done with an inverter testbed using
an e-motor emulator, and the complete
Electrical Drive Unit (EDU)
can be calibrated on the e-drive testbed.
But with so much being done
on the inverter and e-drive testbeds,
what is left for the system testbed?
“The challenge lies in securing the
integration of all the control units
of the vehicle, especially since a BEV
is typically equipped with connectivity
options besides components
for the electrical powertrain itself,”
says Mats Ivarson, Chief Engineer
Testfield Innovation and Operation
at AVL.
Throughout the development process
there are usually multiple loops
of testing required to secure safety
and functionality of the High Voltage
(HV) network in the vehicle.
Without all tests being passed, the
software suite cannot be released for usage. Besides the HV tests for the
in-vehicle systems, charging tests must also be conducted to ensure safety
and the correct functionality. This effort is highly significant since there are,
for example, many different component and system providers, safety and
performance standards and power levels. However, when systems fail, the
customer’s dissatisfaction is directed to the vehicle OEM. Therefore, there
is a high level of motivation to conduct comprehensive testing in order to
secure robustness to known potential disturbances, and continuously add
newly discovered disturbances to the testing program.
Electric
Powertrains
Create a Shift
in Testing