A new concept in modular motor drive systems

This paper describes a comprehensive drive system to cover all the needs of the variable speed drives market at higher power levels (LV up to 575 V AC supply). Its adaptability stems from its modular approach; allowing the use of programmable or alternative control sources by means of a standardised interface to the option of a variety of power stages. These easily removable stages range from simple rectifiers, through DC thyristor output stages, to complex inverter units using input and output bridges based on IGBTs. Higher power requirements are accommodated by paralleling smaller units mounted in a `rack´ arrangement. The system has also been designed to allow the use of common DC link schemes: a growing need in multiple drive work utilising inverters. An important advantage of the system is the ease by which new developments in power devices may be incorporated with a minimum of disruption to the overall design. The original concepts are discussed, and examples of the applications given