Evaluation Engineering - 23

"The benefit of
HIL testing is
that engineers
can validate their
control code for
a full range of
operating and
fault conditions
without damaging
prototype power
supplies."

Keysight Technologies E36200 Series 200- and
400-W autoranging power supplies.
Copyright Keysight Technologies. Reproduced
with Permission.

Lennon, market manager for power electronics control design.
Lennon identified a trend over the past
year toward advances in hardware-in-theloop (HIL) testing.1 "HIL testing helps engineers validate the control software they
program on a microcontroller or FPGA,"
he said. "The HIL test system consists of a
computer with appropriate I/O that runs
the analog components as a real-time simulation." The real-time simulation model
consists of code generated from a model
developed in Simulink and other software,
he said, adding, "The benefit of HIL testing is that engineers can validate their
control code for a full range of operating
and fault conditions without damaging
prototype power supplies."

Lennon cited several challenges in
power-supply design. "Power supplies are
often required to operate in conditions
with varying loads and sometimes fluctuating power inputs," he said. "Simulink
lets engineers design their digital control algorithms in models where these
varying conditions can be simulated."
He pointed out that fault conditions can
also be simulated. "Using simulation
helps engineers uncover errors in their
control algorithms before they move to
prototype testing," he said.
MathWorks serves a variety of application areas. "Simulink can be used to
model most electrical systems, and the
models can generate code that can be run
as a real-time simulation," Lennon said.
"This means that engineers can begin validating the control code for their power
supply against a real-time simulation of
an electric-vehicle drivetrain, a solarpanel system, a microgrid, etc."
Keysight Technologies offers a variety
of software solutions, ranging from simulation to test automation. "Our PD1000A
Power Device Measurement System for
Advanced Modeling paired with our
Advanced Design System (ADS) simulation solution enable thermal simulation
of complex power-converter designs," said
Ryo Takeda, power semiconductor solution architect; Bernhard Holzinger, power
semiconductor technical architect; and
Mike Hawes, power solution consultant.
The combination targets industries such
as HEV and EV manufacturers who are
migrating their power-conversion designs
to wide-bandgap devices.
Bill Griffith, who works in product marketing at Keysight, commented, "Keysight's
DC power solutions combine custom hardware and software to solve industries'
toughest test challenges. Examples include
IoT battery-life testing, photovoltaic (PV)
string inverter testing, HEV/EV testing,
and single- and 2-quadrant high-power
testing with a regenerative power supply."
He added that application-specific
software allows high-performance power supplies to test a variety of devices.
The software includes distributed solar
array simulator control platforms for
testing PV string inverters in real-world
conditions as well as for implementing

industry-standard test-automation strategies in accordance with the EN 50530 standard2 for PV inverter MPPT (maximum
power point tracking) efficiency tests.
Specific Keysight offerings include the
DG9000A advanced/multi-input PV inverter test software. "Distributed solar
array inverters are difficult to test," said
Griffith. "Missing test points leads to
an inaccurate representation of energy
conversion." Keysight's DG9000A can test
multiple input inverters and manage up to
12 separate MPPT operations simultaneously, he said.
The company also offers Solar Array
Simulator (SAS) Control Pro as part of
its BenchVue software, which automates
static and dynamic EN 50530 MPPT test.
Simply input the test parameters, and
click "Start Test," said Griffith, adding,
"Once the test is complete, SAS Control
Pro creates a report formatted to the EN
50530 standard."
Griffith also said, "Keysight has formed
an automotive and energy group to continue building DC power solutions with
state-of-the-art hardware and software.
Keysight PathWave Test 2020 software
suite enables 5G, IoT, and automotive
engineers and managers to streamline
product development processes and facilitate rapid decision making."
Finally, Tektronix's recently released
I-V tracer software allows the Keithley
2400 Series Graphical SourceMeter instruments to behave as modern replacements to old Tek curve tracers like the 370
and 576, according to Wilson Lee, technical marketing manager, Americas. "We
developed this software in collaboration
with several customers to address needs
in areas like failure analysis and incoming
inspection, where benchtop instrument
use and immediate feedback is a must,"
he said. "One of the great benefits of the
software is that it exists on the SMU itself,
so you can easily transport a curve tracer
around a lab under your arm!"
REFERENCES

1.	Hardware-in-the-Loop Testing for Power
Electronics Control Design, White Paper,
MathWorks, 2019.
2.	Overall efficiency of grid connected
photovoltaic inverters, EN 50530, European
Standards, 2010.

APRIL 2020 EVALUATIONENGINEERING.COM

23
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