HOW2POWER TODAY

ISSUE: January 2025

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IN THIS ISSUE:

» Assessing Performance Of A 10-kW String Inverter Based On GaN FETs

» Designing An Open-Source Power Inverter (Part 23): Inverter Driver Design Refinement

» Focus On Magnetics:
The Importance Of Knowing Magnetic Core Saturation Field Strength For Accurate Hysteresis Loss Calculation

» Industry Event:
Call For Papers: World Magnetic Conference–Coil Winding Innovation In The Spotlight

» Power Products

» New on How2Power.com

» Other Top Power News

I began this new year with my usual trek to CES where I joined 141,000+ attendees in a quest to see the latest tech from 4500+ exhibitors. While the scope of this event is extremely broad, you don’t have to look very far to discover exhibits relevant to power design. Many of the tech trends driving development of power electronics, which were seen at previous shows, continued to be on display at CES 2025: just about everything that moves is being electrified, robots of various kinds abound, portable consumer devices and smart appliances are ubiquitous, and solar energy and energy storage products for the home are becoming commonplace. The batteries and chargers that support such applications were on display too. Despite my attention here to the power aspects, it was the AI theme that continued to be dominant at CES, perhaps even more so this year with Nvidia’s CEO Jensen Huang giving the opening keynote. Huang introduced Project DIGITS, a personal AI supercomputer based on the company’s new GB10 Grace Blackwell superchip, and presented other AI news and predictions. This too is power-relevant as AI is driving advanced power supply development. I’ll drill down further into the power-related news from CES 2025 in upcoming coverage. But for now, I’ll just observe that CES, which showcases an ever-widening array of tech products and services beyond consumer electronics, also seems to be expanding in other ways. For example, there appeared to be more country pavilions this time, both in the Eureka Park startups section and in other exhibit halls. Among these, the Korea pavilion stood out, not only for its many startups, but also its multiple universities. In addition, various industry and governmental organizations had a strong presence at this show. Seeing this range of stakeholders participating in CES together with the vendors from across the electronics ecosystem conveyed a real sense of how globally dispersed and competitive the tech industry has become, and how economically vital it is in all regions.

HOW2POWER EXCLUSIVE DESIGN ARTICLES

Assessing Performance Of A 10-kW String Inverter Based On GaN FETs

by Riccardo Ruffo and Vedatroyee Ghosh, Texas Instruments, Freising, Germany

The implementation of wide-bandgap power devices based on gallium nitride (GaN) helps string inverters in photovoltaic systems achieve lower switching losses. At the same time, they enable use of much smaller magnetic components thanks to a significant increase in switching frequency compared to silicon-based power devices. In this article, we’ll describe a low-cost 10-kW single-phase string inverter based on GaN power devices. The string inverter consists of two nonisolated power stages—a dc-dc converter comprised of two interleaved boost converters and a dc-ac converter. The design’s high efficiency also enables you to connect a nonisolated dc-dc converter directly to an energy storage system (ESS), and to install it on the same heat sink with other power-conversion systems. Read the article…

Interesting aspects of this design include
the bidirectional operation of the dc-dc
stage that manages power flow to and from
the battery, the use of the HERIC topology
in the dc-ac stage, and digital control of
all three power stages using a single MCU.

In this part we correct some errors in
the H-bridge circuitry by making adjustments
to the bypass capacitance, changing the
off-biasing of the high-side driver for a
better voltage margin, and other fixes.

Designing An Open-Source Power Inverter (Part 23): Inverter Driver Design Refinement

by Dennis Feucht, Innovatia Laboratories, Cayo, Belize

Experienced design engineers can anticipate almost all of what needs to be considered in a design project. More involved projects, such as the design of an oscilloscope for instrument engineers, are straightforward for perhaps 95% of the project before anomalous behavior is encountered on the bench. The final 5% of the project becomes a research effort to find causes for unanticipated problems that can absorb 50% of the time of the project. This is why in the 1960s at Tektronix, planners would multiply the project time resulting from careful estimation by two to devise a more realistic project schedule. The Volksinverter design is no exception, and refinement of the earlier design work discussed in previous parts is necessary. In this latest installment in the Volksinverter series, some further attention is given to the design of the inverter stage. Read the article…

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

The Importance Of Knowing Magnetic Core Saturation Field Strength For Accurate Hysteresis Loss Calculation

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

Magnetic cores manufacturers very seldom provide full hysteresis loops for their products. Although a previous work has shown how to calculate core power loss using an expression for the hysteresis loop derived from a core’s data sheet specifications, it assumed values H_sat and -H_sat based on B_sat/µ, without clearly defining how to determine the acceptable value of permeability. In this article, a method is proposed for defining H_sat based on an analytic expression for the core permeability dependence on the magnetizing field induced in the core. It assumes dependence of permeability on the applied magnetic field and a value of an admissible permeability loss due to the magnetization strength H rise. Using the new expression for H_sat derived here, we’ll see how it can be applied to the previously derived expression for hysteresis loss in a design example. Read the article…

INDUSTRY EVENT

Call For Papers: World Magnetic Conference–Coil Winding Innovation In The Spotlight

Coiltech North America 2025, which will be held June 11-12 in Novi, Michigan, is set to become a key platform for the full coil winding supply chain. A two-day gathering of the most innovative players in electric motors, transformers, and generators, this edition of Coiltech secured over 200 booked booths in the first six months since the announcement of its launch. Central to the event is the World Magnetic Conference (WMC), a prestigious forum connecting academic and industry leaders to share cutting-edge research, technical advancements, and practical solutions for the design, production, and maintenance of energy-efficient systems in power grids and industrial equipment. Read the full story…

POWER PRODUCTS

NEW ON HOW2POWER.COM

In Industry Events:

“Electronica 2024 Showcased Power Developments For AI, EVs, Robots And Other Applications”

by David G. Morrison, Editor, How2Power.com

In this article I present my impressions of Electronica 2024, discuss power-related developments presented at the fair, and offer a slide show of interesting power-related demos encountered on my tour of the exhibition. Read the article …

OTHER TOP POWER NEWS

onsemi has entered into an agreement to acquire the SiC JFET technology business, including the United Silicon Carbide subsidiary, from Qorvo for $115 million in cash.

The U.S. Department of Energy (DOE) has announced publication of the 2024 Report on U.S. Data Center Energy Use produced by Lawrence Berkeley National Laboratory, which outlines the energy use of data centers from 2014 to 2028.

Infineon Technologies and Eve Energy, a manufacturer of lithium batteries, have signed a memorandum of understanding aimed at enabling comprehensive battery management system solutions for the automotive market.