AbstractIn this work we determine a mathematical model of a possible practical realization of the drive effecting the method of speed control of an asynchronous three-phase motor, based on the chopper control, here defined as“nonsynchronous”control, of the rotor currents performed simultaneously on the three phases at sufficiently high and constant frequency, and independently of that of the rotor currents.In particular, a procedure is described for obtaining a mathematical model of the drive in question, which makes it possible to generate automatically all conduction configurations that depend on the ON-OFF state of the semiconductor elements present in the static converters, thus obviating both a priori identification of these configurations and determination of the corresponding differential equations.This approach is of general validity and can be utilized for the study of drives, which consist of d.c. or a.c. motors and static converters.