ELECTROMAGNETIC COMPATIBILITY OF DC MACHINES AND DRIVE SYSTEMS

摘要

Due to new legislation, electromagnetic emissions from electrical motors and drive systems have become a major consideration. Therefore, as part of their work in rehabilitation engineering, the authors have initiated an investigation into the electromagnetic compatibility (EMC) of motors and drives, initially focusing on DC systems.rnThis paper describes the electromagnetic interference (EMI) produced by both brushed and brushless DC motors and drives, and despite the fact that the EMI from such systems tends to contain a random element, by using appropriate measurement techniques the emissions can be measured to a mean repeatability of less than 0.35dBμV.rnA new method of representing electromagnetic emissions is presented, which gives a clear indication of the source of the EMI and the predominant frequencies. It is in the form of an annular plot which is highly suited to comparing similar types of motors and for examining the effects of parameter variations of both motors and drives. Hence, it aids understanding of the causes of EMI, and assists in the design of motors and drives with acceptable levels of EMC.