HOW2POWER TODAY

ISSUE: May 2024

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IN THIS ISSUE:

» Characterizing Dynamic C_OSS Losses in 600-V GaN HEMTs

» A Guide To Designing Your Own Rogowski Sensor (Part 2)

» Focus On Magnetics:
Designing An Open-Source Power Inverter (Part 17): Transformer Winding Design For the Battery Converter — Alternative Configurations

» Industry Event: ITEC 2024

» Power Products

» Industry Event: EnerHarv 2024

» Other Top Power News

The market reports tell us that usage of GaN power devices is rising quickly. For example, a recent post by Yole discussing the GaN power device market says, “Revenue is forecast to rise at a compound annual growth rate (CAGR) of 46% over the 2023-2029 period.” Although this type of data, doesn’t tell us how many engineers are designing with GaN power semiconductors, we can infer that those numbers are probably growing too. So it would seem that more designers are discovering the benefits of GaN devices, but also the new challenges they bring. One of the well-known benefits is these devices’ ability to operate more efficiently than silicon at higher switching frequencies. Nevertheless, as switching frequencies go higher, the losses associated with charging and discharging of C_OSS become more important as noted by Stefano de Filippis and Matthias J. Kasper in their article in this issue. And as they explain, such losses are not easy to characterize and some of the existing methods for doing so do not accurately reflect actual device usage. De Filippis and Kasper go on to present an addition to the calorimetric characterization method that both eases test setup and speeds the temperature measurements needed to accurately determine C_OSS losses for 600-V GaN devices under real operating conditions. Such articles would seem to signal the progress that’s being made in adoption of GaN technology as more of the articles being published move beyond the basics of designing with GaN power switches, to more advanced subjects that help engineers design with these transistors more effectively. This edition of the newsletter also presents part 2 in Gregory Mirsky’s series on designing a Rogowski coil sensor, further details of Dennis Feucht’s transformer design procedure, the latest power component news and more.

HOW2POWER EXCLUSIVE DESIGN ARTICLES

Characterizing Dynamic C_OSS Losses in 600-V GaN HEMTs

by Stefano de Filippis and Matthias J. Kasper, Infineon Technologies Austria, Villach, Austria

Every time a power device is switched, its output parasitic capacitance C_OSS incurs a loss because it is charged and discharged. C_OSS losses, then, are proportional to switching frequency. Because GaN enables higher-frequency operation, C_OSS is more of a consideration for GaN power HEMTs than MOSFETs made from other materials. However, C_OSS losses are not easy to characterize and the industry still lacks a solid understanding of the underlying physics mechanism. This article will explore different methods for characterizing C_OSS losses — nonlinear resonance, Sawyer-Tower, and calorimetric. After explaining the advantages of the calorimetric characterization method, it will present a novel addition to this method that simplifies setup calibration and speeds C_OSS loss characterization by eliminating the need to wait until the thermal system has reached thermal equilibrium. Read the article…

As the proposed test method
demonstrates, C_OSS losses are
dependent upon slew-rate,
displacement current (I_COSS),
switching frequency and
drain-source on-resistance.

An integrator based on a fast op amp
U2 can restore the measured current
waveform and scale it to the needed
output voltage range. C3, R7 and R1
are integrating components, while R8
is a phase correction resistor.

A Guide To Designing Your Own Rogowski Sensor (Part 2)

by Gregory Mirsky, Design Engineer, Deer Park, Ill.

In part 1 we learned that a response to the trapezoidal current of a Rogowski coil is essentially a derivative of the measured current waveform. To restore the current waveform, we have to integrate the coil’s output voltage. Analytical expressions for these waveforms were derived in part 1 and as noted in that article, we have to push the exponential pulse through an integrator to obtain the expected rectangular output. In this second part of the article, we’ll derive the integrator’s transfer function and then show how this is used to select the integrator’s key components. Read the article…

FOCUS ON MAGNETICS       
Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology

Designing An Open-Source Power Inverter (Part 17): Transformer Winding Design For the Battery Converter — Alternative Configurations

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

This latest installment in the Volksinverter design series takes the winding design procedure and formulas from part 16 and applies them to winding configurations in search of the optimal winding plan. The winding sequence is primary first (onto the center-leg of the core), secondary last (exposed to ambient). In general, all windings of the input current polarity are primary and all windings of opposing output currents are similarly lumped together as the secondary winding(s). The Volksinverter has two identical primary windings and only one secondary winding. In part 16 the winding geometric configuration (sequential) and allotment of winding areas in the window were determined, and given the turns, the maximum bundle sizes were determined. But we also need to consider eddy-current resistance ratios in winding design plans, which we’ll do here. With large bundle radius, winding aspect ratio becomes a significant geometric parameter affecting winding design. Consequently, we’ll examine the wire size fit for the given winding area dimensions. Read the full article…

INDUSTRY EVENT

ITEC 2024 Will Tackle Latest Issues In Vehicle Electrification

The IEEE Transportation Electrification Conference & Expo (ITEC), which will be held June 19-21, 2024 at the Donald E. Stephens Convention Center in Rosemont, Illinois, has published its final program. The program includes a full slate of technical lectures, tutorials, short courses and keynote talks with speakers representing a range of organizations in the transportation electrification field. Meanwhile, ITEC 2024’s panel presentations highlight many of the top-of-mind issues facing the industry today. These include “Sustainable Freight Transportation,” “Off-Highway Vehicle Electrification, “Electric Motors are the Forgotten Link in the EV Chain,” “Emerging EV Charging Technology and Policy Trends,” “Advanced Battery Technology,” and “Grid-Tied Electric Vehicle Integration with Artificial Intelligence Advancements.” Read the full story…

POWER PRODUCTS

INDUSTRY EVENT

EnerHarv Workshop Announces Confirmed Speakers

The 3rd EnerHarv International Energy Harvesting Workshop, which will be hosted by the Noise in Physical Systems (NiPS) Lab at the University of Perugia in Perugia, Italy, 26-28 June, 2024, has announced its confirmed speakers. This event will be live and in-person including keynotes and paper, poster and demo presentations from energy harvesting technology leaders from both academia and industry. This year, EnerHarv will be co-located with the NiPS Summer School. Read the full story…

OTHER TOP POWER NEWS

On August 6, 2024, the IEEE EMC + SIPI symposium will feature a keynote by Ed Godshalk on “The Story of the Transatlantic Telegraph and the World’s First Internet”.

Power Integrations has announced an agreement to acquire the assets of Odyssey Semiconductor Technologies, a developer of vertical GaN transistor technology.

Apex Microtechnology has announced the launch of its radiation-tolerant product portfolio and highlighted some of the notable space missions on which APEX products have been onboard.

Infineon has provided FOXESS with power semiconductors to improve the efficiency and power density of energy storage applications.