IEEE Power Electronics Magazine - December 2020 - 4

From the Editor

by Ashok Bindra

Robotics Power Systems
Present Many Challenges

esigning and developing a
power delivery system for a
robot, both static or mobile,
is challenging as there are several factors that must be taken into consideration. Besides powering a broad variety of loads that could be part of a
typical robot, such as high-power
artificial intelligence (AI) computing
systems, motor drives, sensors, RF
communication systems, logic boards,
and microprocessors/microcontrollers
to name a few, there is also the electro-magnetic interference (EMI) to
suppress. EMI problem is natural in
such designs because the system is
closely-packed and dense and uses
high-power switching regulators. As
a result, robotics power systems
confront many challenges that are
unique to these products. Consequently, new approaches are needed to address them.
In the cover feature " Rethinking
the Power Delivery Networks of Mobile Robots, " Anna Giasson and Stavros Dokopoulos of Vicor Corporation
explore fundamental engineering
principles and discuss experiences
from supercomputing applications.
Applying the experience gained, the
authors show how the performance
and design flexibility of advanced
robotic power systems can be enhanced by leveraging fixed-ratio
power converters and high-efficiency
Digital Object Identifier 10.1109/MPEL.2020.3033574
Date of current version: 16 December 2020

IEEE POWER ELECTRONICS MAGAZINE

wide-input-range buck or buck-boost
regulators. In essence, this article discusses two approaches:
1) The use of buck and buck-boost
regulators with wide input voltage
ranges in power delivery networks
(PDN) up to 75 V, within the 110 V
dc safety extra-low voltage limits
per IEC. This allows low voltage
robotic power conversion stages to
be smaller than their isolated dc-dc
counterparts, and/or be adaptable
to higher or lower battery voltages
used on larger or smaller platforms.
2) The use of fixed-ratio converters
to scale the voltage of sources efficiently up or down as well as
enhancing their dynamic response
capabilities within the same PDN,
or to adapt it to a much higher voltage source.
In summary, the above two power
topologies provide the designers with
multiple options to consider for a mobile robotic system that meets their
design goals.
The advent of AI has brought a
challenge to the engineers specialized
in power electronics which is already
a complex, interdisciplinary and fastmoving technology. AI provides very
powerful tools for design, simulation,
control, estimation, fault diagnostics,
and fault-tolerant control of power
electronic systems, which are particularly important in modern smart
grid and renewable energy sources
(RES). In the next feature " Artificial
Intelligence Techniques: How Can it

z December 2020

Solve Problems in Power Electronics? " Prof. Bimal K. Bose of the University of Tennessee, Knoxville, TN,
presents fundamental AI techniques
that have recently emerged as the
powerful and advancing frontier in
power electronics to bring intelligence to a wide range of traditional
and non-traditional applications,
including RES and motor drives.
To create more robust gallium nitride (GaN) devices, the third feature
" Intrinsic Failure Mechanisms in
GaN-on-Si Power Transistors " by Alex
Lidow, Robert Strittmatter, Shengke
Zhang, and Alejandro Pozo, Efficient
Power Conversion Corp., discusses
the test-to-fail methodology. This article shows that by understanding
the intrinsic failure mechanisms that
may limit device performance under
stress, the devices demonstrate flawless reliability in a wide variety of realworld conditions. For eGaN FETs, the
article indicates that 123 billion device
hours of use in the field have been
documented covering January 2017
through February 2020 in EPC's key
automotive and telecommunications
applications. As a result, there has
been a total of three device units that
have failed. These three device units
failed for an extrinsic failure mechanism, a defect in the wafer fabrication
that has since been fixed, according to
the article.
The fourth feature " How to Design
and Implement an Adapter Power
Supply with Active Clamp Flyback " is

IEEE Power Electronics Magazine - December 2020

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