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IN THIS ISSUE:
» GaN-Based Wireless Power Enables Efficient, Seamless Multi-Device Charging
» Transmitting Overpower Alert Signals With Low Latency Boosts Reliability Of Bus-Bar Power Lines
» More-Efficient Boost Converter Extends Battery Life For Wearable Medical Patches
» New on How2Power.com
Power Supplies for Industrial Applications
FAE Confidential
» Focus On Magnetics:
Debunking The Gapped Inductor Myth
» Spotlight On Safety & Compliance:
FAE Confidential
Power Factor Correction (Part 1): Why We Need It And How It Evolved
» New Power Products
» Other Top Power News
From the Editor's Desk David G. Morrison
Editor, HOW2POWER TODAY
For most of its applications, the main goal of wireless charging is simple — make charging easier, if not effortless. That simple objective leads to many challenges and complexities, both technical and market-related. In this issue, an article by Dan Costinett and his colleagues at the University of Tennessee discuss their work in developing a wireless power transfer system that overcomes some key limitations of existing wireless power designs such as limited power levels, low efficiency and lack of spatial freedom. The authors describe in detail the design of a single transmitter, multireceiver wireless charging system for use in a work station. Their prototype system supplies 100 W to five loads over a large charging area, while achieving >90% full load efficiency. Innovative coil design, use of GaN FETs, and a streamlined power architecture are among the techniques these researchers applied to achieve their goals. Others in industry may be pursuing similar paths as they attempt to deliver the benefits of wireless charging to both existing and new applications. No doubt some of these applications will be in industrial settings, and in this issue of the newsletter, we introduce How2Power’s new section on Industrial Power Supplies, which presents information on the companies that make them, where they are used, and the latest new products. This issue also presents a new installment of FAE Confidential, and articles on transmitting overpower alert signals over bus-bar power lines, a boost converter for wearable medical patches, a debunking of the gapped inductor myth, the origins of our power factor correction requirements and much more.
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HOW2POWER EXCLUSIVE DESIGN ARTICLES 
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GaN-Based Wireless Power Enables Efficient, Seamless Multi-Device Charging
by Daniel Costinett, Jie Li, Jingjing Sun and Peter Pham, The University of Tennessee, Knoxville, Tenn.
At present, commercial implementations of wireless power transfer (WPT) are largely limited to low power, low efficiency, and a charging paradigm where each device must be well aligned with a dedicated charger. This approach fails to capitalize on the promise of spatial freedom and effortless, pervasive charging which makes WPT attractive. In this article, the authors describe the design of a WPT system for a workstation in which a single transmitter seamlessly charges electronic devices of varying power levels, simultaneously, when placed in arbitrary coplanar positions above a 0.5-m x 0.5-m charging area. This work, in collaboration with Power America, leverages the capabilities of GaN transistors to enable new design paradigms for WPT systems.
Read the article…
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In the proposed WPT system, a transmit coil design provides
uniform coupling to multiple receiver coils, while use of
high Q coils and a streamlined power architecture increase
the system’s high power conversion efficiency. |
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In a dc bus-bar power distribution system,
hot swap controllers can isolate a faulty
node that’s experiencing an overcurrent condition.
But additional components will be needed to maintain
regulation under fault and while signaling the system
to throttle back on power consumption. |
Transmitting Overpower Alert Signals With Low Latency Boosts Reliability Of Bus-Bar Power Lines
by Viktor Vogman, Power Conversion Consulting, Olympia, Wash.
For server racks with dc bus-bar power distribution, the power supply is usually sized for a full-rack configuration running software that generates the highest power consumption. Such overly conservative power delivery architectures present an opportunity for significant reduction in power supply size and cost. For example, when operating in a failure/nonredundant mode, smaller power supplies can detect an anomalous excessive power condition and then generate a fast interrupt in the form of an overpower alert that signals to the servers to throttle back until the redundancy gets restored and/or power comes back into an acceptable range. This article presents a study of the conditions necessary for reliable transmission of overpower alert signals across a dc bus-bar power delivery network (PDN) in a high-power server rack. It also introduces a simple technique for broadcasting the alert logic signal across such PDNs with a small transmitter/receiver and with minimal latency in node throttling.
Read the article…
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More-Efficient Boost Converter Extends Battery Life For Wearable Medical Patches
by Eddie Lee and Nazzareno (Reno) Rossetti, Maxim Integrated, San Jose, Calif.
With their ability to continuously record and transmit a patient’s state of health, wearable medical devices are transforming the healthcare industry. But these devices pose some difficulties in power management. This article reviews the challenge of powering a wearable medical patch placed on a patient’s chest while meeting the requirement to operate for five days on a single disposable zinc-air battery. When regulated by a typical boost converter, the battery voltage fails to meet the device operating time requirement. However, when powered by a high-efficiency, low-quiescent boost converter such as the the MAX17224, the same device meets and exceeds the five-day runtime demand.
Read the article…
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In this medical patch, the sensors
collect data for 4 sec, which is then
transmitted in 100-ms bursts by the
radio to a centralized receiver. |
NEW ON HOW2POWER.COM
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Power Supplies for Industrial Applications
This section presents information and resources to help designers select and evaluate power supplies for industrial applications, which typically feature challenging or unusual electrical, mechanical and/or environmental requirements along with demands for high reliability and long operating life. These power supplies find use in areas such as industrial/factory automation; railway; ships; industrial vehicles and construction equipment; energy generation, power utilities and power distribution; mining; oil & gas; medical equipment and scientific research.
Visit this section
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FAE Confidential
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In this latest installment of FAE Confidential, the authors continue to discuss how the role of semiconductor FAEs has changed over the years. How and why did the role change so radically? Here in part 2 of their series the authors attempt to answer that question by examining the period when companies began to question the value of their FAEs.
Read The War On FAEs (Part 2): New Management Brings Benign Neglect
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FOCUS ON MAGNETICS
Sponsored by Payton Planar Magnetics
A monthly column presenting information on power magnetics design, products, or related technology |
Debunking The Gapped Inductor Myth
by Gregory Mirsky, Vitesco Technologies, A Spinoff Of Continental Automotive Systems, Deer Park, Ill.
While browsing the Internet, the author recently discovered that many engineers do not treat gapped magnetics correctly: some state that an air gap increases the saturation flux density, others say that inductors based on an air gap in the magnetic core store energy in the gap only. Neither statement is true because the gap in the core just lowers the core’s effective permeability, leaving the core material saturation flux density intact. And the energy is stored in the whole gapped magnetic, with the energies stored in the gap and the rest of the core in reverse proportion to the permeabilities of air and the magnetic material. Sometimes, the energy stored in the core may be substantial. Anyway, we have to deal with all possible cases of magnetic energy storage distribution over the gapped core as will be explained and illustrated in this article. A new approach to designing gapped-core inductors is also presented.
Read the full article…
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SPOTLIGHT ON SAFETY & COMPLIANCE
Sponsored by Power Integrations
A monthly column discussing standards and regulatory requirements affecting power electronics |
Power Factor Correction (Part 1): Why We Need It And How It Evolved
by Kevin Parmenter, Chair, and James Spangler, Co-chair, PSMA Safety and Compliance Committee
The application of power factor correction (PFC) in switched-mode power supplies is well established and the circuits used to implement active PFC are widely known. Along with knowledge of PFC circuits and components, many engineers likely have an awareness of the PFC standards that govern product compliance. But when it comes to why these PFC requirements are in place and what were the industry or market conditions that drove their adoption, the record is not so clear. Here in part 1 we review the history of how PFC evolved and the technical requirements it produced. This discussion includes a review of the IEC 61000-3-2 power factor standard and the limits it imposes on harmonics generated by non-resistive loads, and where PFC is currently required.
Read the full article…
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 — POWER PRODUCTS IN 3 IMAGES OR LESS
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 ARPA-E has announced funding opportunity announcements for four new programs funding new technology development for electric aviation, feedstock monitoring, and carbon storage technology, as well as an opportunity to scale energy technology.
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