SAE Update - May 2024 - 23

Overcoming EV drivetrain
testing challenges
TECH FOCUS:
TESTiNg AND DigiTAl TwiN
Hybrid and electric vehicles use four-quadrant
motor/inverter technology, meaning that the electric
motor can control velocity or torque in either
direction-the motor can accelerate, run, and
decelerate forward or backward. A four-quadrant
motoring dynamometer with the ability to drive or
load in either direction is essential to simulate/test all
modes of operation in a hybrid or EV. A standard
dynamometer is not capable of testing the system
during braking when it is in regenerative mode.
Creation of high-efficiency, AC-powered systems
typically involves the use of three-phase, inverterbased
technology to precisely control the electric
motor(s) in the system. These systems tend to be very
efficient but also generate a great deal of harmonic
distortion in the power output. So, in addition to the
motoring dynamometer, a hybrid/EV test system
typically includes a three-phase power analyzer. This
unit must be specifically designed to measure highpower
electrical values with a great deal of harmonic
distortion present.
To meet the need for a system that can fully test
hybrid and EV drive systems, SAKOR developed
HybriDyne, a comprehensive test system for
determining the performance, efficiency, and durability
of all aspects of hybrid drivetrain systems, including
electrical assist (parallel hybrid), diesel electric (serial
hybrid) and full-electric vehicle systems.
HybriDyne integrates components of SAKOR's
DynoLab powertrain and electric motor data
acquisition and control systems. Coupled with one or
more of its AccuDyne AC Motoring Dynamometers, and
one or more precision power analyzers, the modular
HybriDyne can test individual mechanical and/or
electrical components, integrated sub-assemblies, and
complete drivetrains with a single system.
UPDATE
High-voltage battery
simulation and testing
A critical element of hybrid or
electric vehicles is the highvoltage
battery and charging
system. To accurately test a
high-voltage hybrid or electric
drivetrain, the test system must
provide precise, repeatable
high-voltage DC power. Since
battery performance changes
over time depending upon their
charge state, ambient
conditions, and age, they are
typically not acceptable for
powering the DC components of
a hybrid/EV test system. A
standard off-the-shelf power
supply will not work, because it
cannot absorb power from the
regenerative system and may be
damaged or destroyed.
SAKOR developed a SolidState
Battery Simulator/Test
System specifically to test highvoltage
hybrid vehicle batteries
and simulate these batteries in
an electric drivetrain
environment. At the heart of the
system lies a high-efficiency,
line-regenerative DC power
source. During regenerative
modes, absorbed power is
regenerated back to the AC
mains instead of being
dissipated as waste heat, which
May 2024
23
SAE Update - May 2024

Table of Contents for the Digital Edition of SAE Update - May 2024
