The three-phase induction machine with non-salient poles is the most widespread electric motor because of its simple and robust construction; it is perhaps the electrical machine that has the least intuitive operation (Caron and Hautier, 1995). It has been the subject of very many technical publications.
Starting from the equivalent three-phase electrical circuit of the induction machine without neutral current, let us establish initially the relations between the various electrical variables.
Definitions and notation of motor parameters:
Ls = Lm + ls
Lr = Lm + lr
Definitions and notations of mechanical and electrical angular frequencies: