HOW2POWER TODAY

ISSUE: June 2010

To ensure receipt of your newsletter, please add david@how2power.com to your address book.

IN THIS ISSUE:

» From the Editor’s Desk

» How2 Get The Most Out Of GaN Power Transistors

» How To Design A 250-W HID Electronic Ballast

» Comprehensive Flux Estimator Implementation
    Procedures For Advanced Control Of Inverter-Fed
    Induction Machines

» Increasing Active-Mode Efficiency And
    Reducing Standby Power for Energy Star

» New Power Products

» Power Supply Jobs & Technology

» Other Top Power News

The terms “evolutionary” and “revolutionary” get tossed around frequently in discussions about technology. Most developments in electronics fall into the former category, though many are heralded as the latter. However, for technologies to succeed in the marketplace, they need to be a bit of both. Products can be revolutionary in their performance, but they should be evolutionary in other ways. For example, you’d like newer power components to enable revolutionary advances in efficiency or power density; but these components will be easier to adopt if they only require modest or evolutionary changes in the techniques used to design a power supply. Starting in this issue, a series of articles on GaN power transistors will convey this message, explaining how GaN’s revolutionary advances in power supply performance demand relatively modest adjustments in the circuit designs that are currently applied to silicon power MOSFETs. As this article series continues, you’ll learn more about GaN device reliability and how GaN breaks the old rules concerning Vin/Vout ratios in dc-dc converters. Meanwhile, in this edition of How2Power Today, you’ll also read about a more-integrated solution for HID lamp ballasts, a flux estimator for induction motors, techniques for meeting energy efficiency requirements in consumer products, and much more.

HOW2POWER EXCLUSIVE DESIGN ARTICLES

How2 Get The Most Out Of GaN Power Transistors

by Johan Strydom, Efficient Power Conversion, El Segundo, Calif.

Thirty years of silicon power-MOSFET development has taught us that one of the key variables controlling the adoption rate of a disruptive technology is how easy the new technology is to use. This principle has guided the design of EPC’s enhancement-mode GaN (eGaN) transistors. This article explains why eGaN devices are easy to use, describing how they operate and their similarities and differences versus power MOSFETs. With that as background, the article explains the gate-drive requirements for eGaN transistors, and presents suitable discrete and IC-based gate-driver designs for use with eGaN devices. Read the full story…

 

The new eGaN power transistors can be driven with
existing gate-driver ICs or with discrete solutions.

An HID ballast design based on the IRS2573D controller offers a simpler, more–integrated implementation of the standard three-stage topology.

How To Design A 250-W HID Electronic Ballast

by Tom Ribarich, International Rectifier, El Segundo, Calif.

Typical outdoor lighting applications today use high-intensity discharge (HID) lighting technology. HID lamps are difficult to control and the design of the electronic HID ballast to drive them is complex. Some of the functions performed by the electronic HID ballast include ignition, warm-up, constant power control, power factor correction, and protection against all lamp and ballast fault conditions. This article describes an electronic ballast circuit for a 250-W HID lamp using the new IRS2573D HID control IC. Fundamental lamp requirements and control methods are presented, as well as complete circuit schematics and waveforms. Read the full story…

Comprehensive Flux Estimator Implementation Procedures For Advanced Control Of Inverter-Fed Induction Machines

by Ali M. Bazzi and Philip T. Krein, Grainger Center for Electric Machinery and Electromechanics, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Ill.

This paper, which was originally given at the 2009 Electrical Manufacturing & Coil Winding Expo, presents the implementation of a flux estimator for induction machines. Both stator and rotor flux are estimated using the back-EMF method. A procedure for the implementation, calibration, and testing of this estimator on a digital signal processor is given. The procedure is intended for applications in which the estimator is essential but not a primary system development target. The work presented here can be extended to other estimators, especially for advanced inverter-fed motor control applications. Read the full story…

This article views the estimator as a “gray box” within the Control & Estimation block of a typical induction motor drive.

Systems such as set-top boxes contain several
subcircuits, which can be individually turned off
to reduce the system’s overall power loss.

Increasing Active-Mode Efficiency And Reducing Standby Power for Energy Star

Majid Dadafshar, Fairchild Semiconductor, Carlsbad, Calif.

As the need to meet green initiatives becomes more pressing, the International Energy Association will be mandating that suppliers of electronic equipment reduce the power consumption of their systems below 1 W, 0.5 W or even 0.25 W when operating in the standby mode. To reduce this wasted energy below the desired limits, we need to both improve consumer awareness of the problem and improve the available power supply technologies. This paper focuses on the technology side, discussing the main sources of loss in ac-dc power supplies and techniques for reducing these losses during active and standby modes of operation. Read the full story…

  — POWER PRODUCTS IN 3 IMAGES OR LESS

POWER SUPPLY JOBS & TECHNOLOGY

Opportunities in Portable Power Management

If you enjoy reading about career opportunities in power electronics, you now have another source for news about the profession. Starting in the June issue, my column on Career Development appears in Power Systems Design magazine (online now). My first column discusses opportunities for system designers, IC designers, and field application engineers in portable power applications. Read the full story…

OTHER TOP POWER NEWS