Page 27 - PEN eBook December 2022

Power Supplies DESIGN

due to derating required at low AC nominals. It was also limited in functionality and controllability,
requiring inconvenient and expensive external hardware and modifications to the PSU. A better solution
was the HPA1K5 from XP Power, a 1,500-W PSU based on a DSP platform that operates on single-phase

80–264 VAC, with near-zero impact on output rating, for operation in any market. The digital control
eliminated the external circuitry and PSU hardware modifications and added functionality including,
critically, safe shutdown if the system enables signal fails. When proven by the user, through the
supplied GUI, the settings were then factory-configured by XP Power before product shipment. The
customer was able to leverage extra value from the PSU’s I C bus by interfacing to a credit-card–sized
2
single-board computer, which in turn provided a gateway to the user’s cloud network and enabled
monitoring of the end-product power-rail performance globally, from a European control center. The
user has a more competitive product with a component count, cost, and footprint reduced, with
enhanced reliability a welcome bonus.

Products like the HPA1K5 extend their applicability with worldwide ITE and medical (2 × MOPP) safety
approvals and high power density. Nominal outputs can be configured as constant voltage, programmable
0% to 105% of rated nominal, or as constant current 0% to 110% of the rated maximum. Features also
include remote sense, current share for parallel units,
a 5-V standby supply, and a temperature-controlled
SiC MOSFET Reliability
fan.

Similar products in the “HP” range with DSP
functionality from XP Power include the HPL5K0 range, Studies at Ohio State:
rated at 5 kW with three-phase 180- to 264-VAC input,
intended for higher-output-voltage applications, with Short-Circuit Capability
optional nominals of 60 V, 100 V, or 200 VDC. Another
example is the HPT5K0, also rated at 5 kW but with
a three-phase 180- to 528-VAC input, again with high By Sonu Daryanani, contributing writer to Power Electronics News
nominal output-voltage options and two case-style

variants. Both the HPL and HPT ranges include all The superior performance of silicon carbide MOSFETs in high-power switching applications has led to
of the digital control and monitoring described and its widespread usage in some key growth areas, such as in the control of industrial motor drives. One of
fast output slew rates, useful for challenging test the key performance metrics for power semiconductor devices in this application is their short-circuit
applications (Figure 3). (SC) withstand capability. The harsh environment that motor drives operate in can result in overcurrent
levels from fault conditions like inverter shoot-through events and insulation breakdown in the motor
Figure 3: The HP range of products from XP and CONCLUSION windings. Hence, SC capability is one of the reliability tests that device manufacturers perform on their
their programming GUI
The era of “software-defined power” is finally with us, parts. The test is unique because the device is subject to high voltage and high current for particular

with AC/DC products available in which output voltage, current, and all functionality can be controlled stress intervals with the gate pulsed on.
and optimized simply by the user, then embedded in firmware for production, all without compromising
cost and efficiency. Products can operate globally with certifications for a wide range of end applications Professor Agarwal and his team at The Ohio State University have been at the forefront of conducting
and be upgraded or reprogrammed for new ones with a simple connection to a laptop using software reliability studies on various aspects of SiC devices. In this article, we will review some of the findings
1–5
and a GUI available from the manufacturer, putting the user now firmly in control. from their work and highlight some improvements in SC capability by various groups.

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