Electromagnetic Torque Estimations in Dual Inverter fed WRIM Drive

This study evaluates the performance of various electromagnetic torque estimation techniques for double inverter-fed wound rotor induction machine (DI-WRIM) drives. The four estimation techniques being discussed combine stator and rotor fluxes, which are estimated variables, and stator and rotor currents, which are directly measured variables. Two crucial drive performance requirements in high-power applications, including zero-speed full-torque functioning and accuracy in calculating the low-frequency harmonics in torque, are investigated. In addition, two different control methods—current control and direct torque control—are employed for analyzing torque estimation. In the end, the paper suggests selecting the most appropriate torque estimation technique among four options for successful closed-loop operation of DI-WRIM drives. To support the analysis, comprehensive simulations and experimental findings are presented.