Truck & Off-Highway Engineering - April 2024 - 22

Overcoming EV drivetrain testing
CHALLENGES
Effective hybrid/EV test
systems add capabilities
to test high-power
regenerative electric drives,
high-voltage battery and
charging systems and
communicate with smart
control modules.
by Randal Beattie
T
EV powertrain/driveline
test systems help
companies realize
the energy-efficiency
benefits promised by
hybrids and EVs.
ransportation markets have seen a tremendous surge of interest
in hybrid and electric vehicle technology. To gain the promised
efficiency benefits and green profile of these vehicles, it is
important to conduct driveline and component testing during
design and manufacturing that is specially adapted to hybrids and EVs.
Hybrid and electric drivetrains have several features that make
testing them very different from the standard testing conducted on
internal combustion (IC) only systems. Hybrid and electric systems
use regenerative braking, which typically requires the addition of AC
inverter technology and often more complex transmissions.
These vehicles also typically have several module control units
(MCUs), essentially small onboard computers, that control the functions
of major subsystems such as the engine, transmission and
charging system. To properly test these components, the test system
needs to be able to communicate with one or more of these units via
high-speed in-vehicle networks. The technology exists to ensure
proper testing and realization of the energy-efficiency benefits promised
by hybrids and EVs.
Types of hybrid/EV driveline testing
Hybrid or electric driveline testing is conducted at several stages during
the development of a vehicle, and each has an important role to play.
Engineering testing - Accurate measurements are critical so design
engineers can extract every bit of efficiency from their designs.
Most vehicles use three-phase AC motors driven by inverter technology,
so sophisticated power analyzers are needed to properly measure
three-phase AC power with a large amount of harmonic content.
22 April 2024
These test systems tend to be rather complex and are
usually the most sophisticated, with many elements to
be tested and coordinated.
In-process and end-of-line testing - Manufacturing
end-of-line testing is usually performed to verify that no
defects were introduced in the manufacturing process
and that the components will perform to specifications.
Typical tests include operational validation, quick performance
testing, as well as rigorous testing to validate
that high-voltage electrical systems are properly isolated
and are therefore safe to use in vehicles.
In-process testing also may be conducted to test
partial assemblies along the production line. This improves
manufacturing efficiency and significantly reduces
the chance that faulty components will find
their way into the finished product.
Quality control testing - Quality control (QC) testing
is usually done on a percentage of the components
to verify that they perform over the specified range
and are relatively free of defects. For example, a forklift
company may conduct QC testing on a shipment of
imported electric motors. The company would use QC
testing to verify that the shipment coming from its
supplier performs as specified and will not experience
high failure rates in the field. This type of test system is
typically less complex because it does not have to
measure as many items, nor to the degree of accuracy,
as those tested in engineering systems.
TRUCK & OFF-HIGHWAY ENGINEERING
SAKOR TECHNOLOGIES
Truck & Off-Highway Engineering - April 2024

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