Stator and Rotor Temperatures Estimation in Three-Phase Open-ended Winding Induction Motor Drives

The main aim of this paper is to present a stator and rotor temperatures monitoring technique for open-ended winding induction motor drives. The thermal status of the electrical machine is periodically monitored by imposing the current flowing in one of its phases to zero and estimating the magnetizing voltage and the air gap active power absorbed by the motor. From the last quantities a satisfying estimation of both stator and rotor resistances at steady state can be carried out with limited computational efforts, without additional sensing. Then, stator and rotor temperatures are calculated from the change of these resistances. Simulations and experimental tests on a 2.2kW induction motor drive confirm the feasibility and effectiveness of the method.