Multi-phase synchronous motors: Minimum dissipation fault-tolerant control with currents saturation

Multi-phase motor drives are more reliable than the traditional three-phase ones because they can continue to operate safely even in case of faults such as the loss of one or more phases. This paper deals with the control of multi-phase permanent magnet synchronous motors under open-phase fault condition. Using a vectorial approach the optimal current references in fault condition which provide the desired torque minimizing the dissipation and satisfying the limit current are obtained in the rotating reference frame. The approach is as general as possible: the proposed control law can be used for any shape of the rotor flux, for a generic odd number of phases and in presence of one or more phase failures.