FREEDM researchers Partha Das, Subhransu Satpathy, and Subhashish Bhattacharya were recognized in the April 2025 issue of the Products Newsletter from the IEEE Power Electronics Society for their recent paper in IEEE Transactions in Power Electronics titled “Postfault Operation of Three-Level Inverter Driven Six-Phase PMSM With Enhanced Torque–Speed Region.” The full paper can be found here and the abstract is below.

“This article presents an open-switch postfault operational technique with enhanced torque–speed region for three-level (3L) active neutral point clamped (ANPC) inverter-driven symmetrical six-phase (SSP) permanent magnet synchronous machines (PMSMs). Maximum torque (MT), minimum loss (ML), and single three-phase (STP) operations are commonly used for the postfault operations of six-phase drives. The maximum possible torque and speed in these operations are generally limited by voltage, current ratings, and the neutral point configuration of the motor. To enhance the postfault torque and speed operating region, the torque and speed limits in different postfault operational techniques are determined based on the voltage, current constraints, and neutral point configuration of the SSP-PMSM. In this work, a unified postfault operation is proposed that increases the postfault operational limits by combining MT, ML, and STP operations and modifying the neutral point configuration of the SSP-PMSM. In addition, a technique is also presented that modifies the pulsewidth modulation technique to enable full torque operation below 0.5 p.u. speed. The proposed postfault operational technique enables full-speed (1 p.u.) operation by operating in STP mode and full torque operation (1 p.u.) below 0.5 p.u. speed. The postfault operational technique is experimentally validated using a Gallium Nitride (GaN) device-based 3L-ANPC inverter-driven SSP-PMSM.”