Nonlinear Model Suitable for the Offline Cosimulation of Fault-Tolerant PM Motors Drives

This paper presents a dynamic model suitable for accurate co-simulation of fault-tolerant permanent-magnet motor drives featuring independent-phases structure. The model is developed in a circuital form where the usual inductive parameters and back-EMF coefficient are replaced by current and rotor position dependent functions, so that the exact electromagnetic nature and geometry of the machine is accounted over the large flux-current operating range. The model functions are pre-computed by a finite element method analysis of a single phase of the machine, once the magnetic independence among the phases has been verified. Then, the circuital model is solved by a dynamical simulator which implements also the drive system, converter and control, following on the off-line co-simulation approach. The proposed model is validated by experiments carried on a fault-tolerant five-phase permanent-magnet motor-drive for aeronautical application, controlled by BLDC technique. The results show that the modeling solution is capable to simulate the motor dynamics with a high degree of accuracy, and can be used for an effective rapid prototyping of faulttolerant drives.