Abstract
Variable frequency motor drives (VFD's) have been on the market for many years. Early versions were unreliable and prone to failure. Relatively recent developments in Pulse-Width Modulated (PWM) waveform technology have improved VFD reliability and efficiency. This paper provides an overview of PWM variable frequency drive theory and operation. The second portion of the paper provides an overview of the impact of installing VFD's within the electrical distribution system, including concerns regarding harmonics and power factor. NOTE: The views expressed in this paper do not necessarily represent the views of the United States of America, the U.S. Department of Justice, or the Federal Bureau of Prisons.
Massey, G. W. (1997). Variable Frequency Motor Drives: Harmonics, Power Factor, and Energy Efficiency. Energy Systems Laboratory (http://esl.tamu.edu). Available electronically from
https : / /hdl .handle .net /1969 .1 /91248.