Multiphase motors had great fault tolerance under stator opencircuit faults. Related facilities, as well as research theories to improve the control strategies, were continuously proposed. However, there were few faulttolerant control strategies based on unified model suitable for multiphase opencircuit faults. A faulttolerant control strategy applying to opencircuit faults in three or fewer phases of the dual threephase permanent magnet synchronous motor (PMSM) system was proposed, which supported better electrical and dynamical performances of the motor. The unified mathematical model for PMSM opencircuit faults in 1~3 phases was presented, and the matrixes representing asymmetry of the motor under faults were extracted. Corresponding decoupling transformation matrixes were derived from voltage equations. Subspaces were also created for harmonics suppression regardless of the harmonic types. With the number of open phases increasing, a faulttolerant control strategy for the neutral point current of threephase open circuit was presented, which aimed at reducing the amplitude of phase currents and increasing the system redundancy. Simulation and experimental results of these faulttolerant control strategies were provided for verification of the theoretical analysis.