A new modular motor-modular inverter concept for medium-voltage adjustable-speed-drive systems

In this paper, a new modular motor-modular inverter concept for medium-volt age adjustable-speed drive (MV-ASD) systems is introduced. It is shown that standard MV motor winding connections can be reconnected into several thre e-phase groups, each powered by a separate three-phase pulsewidth modulatio n inverter, resulting in a high-performance MV-ASD system. The proposed app roach is fault tolerant and can continue to operate at reduced power levels , under inverter and/or motor faults. An example 250-hp four-pole 60-Hz 230 0-V/4160-V motor winding connection diagram along with the associated inver ter configurations is analyzed. Results from analysis are presented on the aspects of faults and motor operation under partial winding excitation. Exp erimental results on a low-voltage (460 V) 10-hp ASD are demonstrated.