electrical machines and drives systems电机和驱动器系统英文原版电气工程教材教程详解.doc

Electrical Machines And Drives Systems电机和驱动器系统英文原版电气工程教材教程 1Introduction and review ofbasic theory1.1 Aim of the bookOn entering the world of electrical machines, the student meets manyconceptual difficulties not experienced for example in the early studies ofdigital systems, with their simple and precise 2-state operation. Moreassistance is required to permit the new-comer to gain confidence indealing with non-linear, 3-dimensional, rotating electromagnetic devices.The purpose of this book is to provide this aid to understanding byshowing how, with a limited number of equations derived from basicconsiderations of power flow and elementary circuit and electromagnetictheory, the electromechanical performance can be explained and pre-dicted with reasonable accuracy.Such an aim, which will permit the calculation of power-input/outputc haracteristics almost close enough in engineering terms to those of thedevice itself, can be achieved by representing the machine as a simpleelectrical circuit - the equivalent-circuit model. This concept is explainedin many books, for example in the author’s companion volume ElectricalMachines and Their Applications. Though more detailed theoretical treat-ment is given there, substantial portions of the present text may beregarded as suitable revision material. This expanded 3rd edition can, as awhole, be considered as a textbook with particular, but not exclusive,emphasis on Electrical Drives, taught through worked examples, for areader having some familiarity with basic machine theory.Perhaps it is appropriate to point out that complete and exact analysis ofmachine performance is so complex as to be virtually impossible. Theadditional accuracy achieved by attempts to approach such methods isprimarily of interest to the specialist designer who must ensure that his 2 Electrical Machines and Drive Systems(1.1)product will meet the user’s needs without breakdown and he must judgewhen the analytical complication is justified. For