One key factor: Determining the nuances of how capacitors handle expected ripple currents. Sam G. Parler, Jr., P.E. Cornell Dubilier Examine a dc link capacitor’s ac ripple current and you’ll realize it arises from two main contributors: the incoming current from the energy source and the current drawn by the inverter. Of course, capacitors cannot […]
Power Electronics Handbook
Fundamentals of fast chargers for phones and notebook PCs
Overlapping protocols and competing standards have created a confusing landscape for USB chargers. Here are the important differences and similarities of most interest to designers. Masashi Nogawa, Staff Systems Engineer Qorvo The first standard for charging via USB connections allowed power delivery at a 7.5-W maximum. Recently the USB standard jumped up to support 100 […]
The advantages of Generation-Four SiC FETs
New silicon-carbide FETs perform better than previous versions and can replace silicon MOSFETs with relative ease. Anup Bhalla, VP Engineering UnitedSiC Wide-bandgap (WBG) semiconductors are now accepted as the future of high-efficiency power conversion. The reason: they provide lower conduction and switching losses than otherwise-comparable silicon-based IGBTs or MOSFETs. Since the introduction of WBG silicon […]
Handling the 48-to-12-V stepdown
A multiphase, interleaved buck converter can reduce bus voltage down to something useful in data center server racks. Brad Xiao, Nazzareno (Reno) Rossetti Maxim Integrated Hyperscale data centers that dissipate hundreds of megawatts demand efficient power delivery beyond the ability of the traditional 12-V power supplies on old server motherboards. A data center on 12 […]
The changing maze of power supply standards
Brexit altered the landscape of standards for power supply products. Here’s an update on the latest revisions. Ron Stull CUI Inc. The usual way of choosing a power supply is to search on the electrical performance parameters the application demands. But today, it is actually more efficient to start with the national or international standards […]
Super-efficient power converters help hovering drones take flight
When the task calls for a aerial system that can hover in place, the often-chosen approach is to employ a tethered drone. A tethered drone, generally a multirotor, gets its power and communications signals via a flexible wire or cable. Where battery powered multirotor drones can exhaust their batteries in 20 minutes or so, tethered […]
Battery breakthrough fatigue
Leland Teschler • Executive Editor For some cheap thrills, try Googling the words “battery breakthrough.” You’ll be presented with page after page of articles breathlessly chronicling one research result after another in energy storage. But you might wonder why, with so many earth-shattering developments, electric vehicles can’t travel 1,000 miles before needing a recharge. The […]
Applying large banks of supercapacitors
It pays to know techniques for mitigating leakage current and over- voltages in uses where several supercapacitors work in parallel. Michele Kinman Advanced Linear Devices Inc. In applications requiring rapid charge/discharge cycles or short-term energy storage, you’ll often find supercapacitors connected in series or parallel. However, there’s a potential problem when supercaps are wired together […]
How wide bandgap technologies stack up
Cutting-edge power device technologies all have a niche. Here’s a rundown on the applications in which each one likely fits. Dr. Gerald Deboy, Dr. Peter Friedrichs Infineon Technologies The process of converting electrical power to different ac and dc levels and to mechanical motion has changed dramatically over the years. The development of “switched-mode” techniques […]
Can a three-phase power supply operate from wye and delta ac inputs?
A few guidelines help clarify what three-phase input voltage best suits a particular large power system. TDK Lambda Technical Marketing AC-DC power supplies rated higher than 2.5 kW frequently have a three-phase ac input. In the U.S. the voltage can be 208/220 Vac or 480 Vac. In Europe, it is a “harmonized 400 Vac” which […]
