Suppression of Three-Phase Short Circuit Current in Dual Three-Phase Surface-Mounted PM Machines with Different Winding Configurations

For dual three-phase surface-mounted PM (DTPSPM) machines, three-phase short circuit (3PSC) is usually assumed to happen in only one winding group whilst the remaining one is normally supplied. In this paper, by fully utilizing healthy winding group (HWG), two suppression methods against 3PSC current are proposed for DTPSPM machines with different winding configurations. The first method is regulating HWG current amplitude and angle. For DTPSPM machines with symmetrical winding configuration, it is found that the $d$ - and $q$ -axis peak 3PSC current can be reduced to its minimum value when HWG current angles are about 90 and 135 electrical degrees, respectively. In addition, the suppression effect can be further improved when HWG current amplitude increases. For DTPSPM machines with asymmetric winding configuration, the suppression effect of regulating HWG current heavily depends on 3PSC start rotor position. The second method is forcing HWG into 3PSC. This method leads to an additional inductance component in faulty winding group, which thus reduces 3PSC peak current. Finally, the theoretical analysis is validated by FE simulation.