Acoustically quiet marine propulsion motors with stator reconfiguration and active magnetic balancing

The present development pertains to high-power synchronous and induction propulsion electric machinery in the range of 1-40 MW. The active magnetic balancing comprises an integral electronic switch for winding segregation using either thyristors, MCTs or IGBTs. The system also comprises a virtual instrument based winding fault detection system including means for classification and identification of winding faults. The fault detection system controls the triggering of the electronic switch forming programmable, segmented primary windings. Each phase is grouped into sub-phases which are individually switched into or out of the excitation supply or load on a sub-cycle interval during the de-energization sequence. The internal fault detection system is able to isolate selected segments of the stator responsive to the level of stator faults detected and derive the mode with the lowest acoustic signature. This uses a spatial attenuation pattern of airgap radial flux established for each stator. A design example is shown for a 40 MW PM propulsion motor. Test results are shown for a 300 hp, 480 V drive motor and a 500 kW linear induction catapult motor