Minimize Winding Losses in High-Frequency Inductors

Tag : electric inductance

Power electronics are rapidly expanding into new applications ashigh-power semiconductor devices increase their rated operatingcurrent and frequencies to higher and higher levels. As a basicbuilding block of virtually all power electronics equipment,inductors have a unique potential for improvement. That's becauseinductors are usually the largest, most expensive andvolumetrically inefficient items in a power system.
 
Consequently, improvements in inductor design can have a greatimpact on the size and cost of the inductor, which can have asignificant impact on the rest of the power electronics design. Oneway to help shrink a power inductor is to reduce its losses at highfrequencies, so that a lower value of inductance may be specifiedand, therefore, a smaller inductor may be used in the system.
 
To lower an inductor's power losses at high frequencies, designersmust understand the role of winding losses and the optionsavailable for reducing those losses. Those options include a newfoil-winding technique that achieves low losses for inductorsoperating at high ripple current and high power levels. Fordesigners looking to optimize inductor designs using Litz wire,there's also a new tool to aid the design process.

This tool takesthe form of a freeware program that allows the user to optimize thestranding and positioning of the winding inside of the availablewinding window. Understanding Winding Losses
There are two principle mechanisms for loss in inductors, corelosses and winding losses. Core losses involve the magneticproperties of the core material, which exhibits power losses in theform of hysteresis and eddy currents within the core itself.Winding losses come from the resistance in the winding, typicallycopper.