A novel concept for multimachine drive systems with rotor time constant estimation

In recent years, multiphase machines are gaining an increasing interest due to the advantages they possess compared to the conventional three-phase machines. One of these advantages is their additional degrees of freedom. In this paper, extensive simulation studies of series connected multimachines system supplied by a single inverter are presented. This system consists of a six-phase induction machine and a three-phase induction machine. The stators windings of both machines are connected in series in appropriate manner. The dynamic decoupling of each machine from the group is obtained using the indirect vector control algorithm. Mathematical modeling of the multimachine system showed the possibility of independent control of each machine in the group. The independent control is demonstrated by analyzing the characteristics of the torque and speed of each machine obtained via simulation of multimachine system under indirect vector control scheme. However, the independent control scheme is model-based thus very sensitive to changes in certain parameters of the series connected machines. To overcome this problem, these parameters are estimated on line and used to update the control scheme. The simulation results obtained demonstrate the improved robustness of the multimachines system under the proposed control algorithm.