Integrated smart power modules will run mechanical loads that would otherwise sap fuel mileage. THOMAS YIM | ON SEMICONDUCTOR GOVERNMENT REGULATIONS are stimulating demands for more economical vehicles that produce not just fewer NOx pollutants, but also less CO2. Vehicle tax policies currently favor less polluting models, and car makers must cope with new legislation […]
Power Electronics Handbook
Forced Air Cooling and Fan Selection
It’s easy to over-specify a cooling fan. But there are ways of keeping temperature down with fans that are sized just right. JEFF SMOOT | CUI INC. THE FIRST STEP in any thermal management task is understanding the thermal path taken for removing excess heat. Most systems, and particularly those that employ an enclosure, will […]
Secrets of measuring
currents above 50 amps
There is an art to getting accurate readings of high current values. It pays to know a few of the tricks. GEORGES EL BACHA, EVAN SHORMAN, HARRY CHANDRA | ALLEGRO MICROSYSTEMS LLC IT CAN BE CHALLENGING to sense currents exceeding 50 A because the task often involves thermal management, must take place in a limited […]
The basics of thermistors in thermal management
Thermistors can reliably switch in thermal protection to keep power electronics cool. SONJA BROWN | EPCOS, A TDK GROUP CO. All semiconductors generate thermal losses, of course. Thermal losses in power semiconductors can range from a few watts to multiple kilowatts. In heatsinks, the conductive capability is typically measured in °K/W. The smaller the conductive […]
The different routes to measuring energy efficiency
Power measurements made with conventional meters can be drastically inaccurate. Here’s how to decide when to bring in a specialized power analyzer. BOB ZOLLO | KEYSIGHT TECHNOLOGIES, INC. IT’S IMPORTANT to measure energy efficiency accurately in applications running from limited power sources such as batteries. And an understanding of how a device consumes energy can […]
Better high-frequency power design through EM simulation
Here’s how a 3D EM simulation can be used to accurately gauge gate-driver trace inductance. JOHN RICE | TEXAS INSTRUMENTS INC. HIGH ELECTRON MOBILITY TRANSISTORS (HEMTS) were first introduced in the early 1980s and are touted for their exceptional switching qualities. These so-called heterojunction, field effect transistors (FETs) were originally developed for high-frequency RF power […]
DC-DC converters with renewable energy in mind
Modern battery, fuel cell and solar cell systems need ways of transferring power in two directions. New dc-dc converters that are bidirectional can eliminate the need for bulky transformers in these applications while bringing more efficient operation. ANKUR PATEL VICOR CORP. ALTERNATIVE energy scenarios involving renewable sources are characterized by the sending of power both […]
A better way to squelch transients
Modern dc-dc converters can double as compact transient suppressors in vehicular electrical systems characterized by a lot of hash on the battery power lines. By TIMOTHY HEGARTY, Non-isolated Power Solutions, Texas Instruments, Inc. THE proliferation of electronic subsystems in vehicles has created a need for small, inexpensive and highly reliable electronics able to operate in […]
Bumpless control for power factor correction
It can be difficult to correct for power factor in converters that have different conduction modes. A special technique can make corrections smoothly. By Joel Steenis, Alex Dumais, MICROCHIP TECHNOLOGY, INC. DESIGNERS of power factor correction (PFC) circuits will invariably notice distortion as the input current approaches zero. The distortion problem becomes progressively worse at […]
Better thermal design means better efficiency
The strategic use of computational fluid dynamics can speed the development of high-tech products. BORIS MAROVIC, JOHN PARRY MENTOR GRAPHICS CORP. TRADITIONALLY, analysis using computational fluid dynamics (CFD) took place late in the design process once changes to part geometries had pretty much stopped. But CFD is starting to be applied at earlier stages of […]
