Frequency Control of a 9-Phase Induction Motor at Switched Supply Sequence

The nine-phase induction motor operating at a variable frequency was presented in the paper. The control method was supplemented with the additional possibility based on the supplied voltages sequence switching of the 9-phase supply system made of the IGBT voltage source inverter. This allows for shaping of the motor mechanical characteristics increasing the maximum torque for a greater number determining the sequence. So, such a motor work can be suitable for some electric vehicles where the sequence switching gives a similar effect as the mechanical gear-box. In this paper the 9-phase motor work comprising the mentioned effects was shown by the results of practical laboratory tests and computer simulations.