Induction motor stator and rotor winding temperature estimation using signal injection method

A new method to estimate the induction motor stator and rotor resistance (R_s and R_r) and temperature (T_s and T_r) was proposed in this paper. Two signals with proper frequencies that yield high sensitivities of terminal measurement to R_s and R_r at a given rotor speed are injected to the induction machine to estimate R_s and R_r. The estimated R_s and R_r are then used to estimate T_s and T_r respectively, according to the relationships between R_s and T_s, and R_r and T_r. Simulation and experimental work have been carried out to verify the proposed method. The proposed method can estimate both stator and rotor resistance and temperature with high accuracy and the estimated R_s and R_r can be updated in real time. It does not require additional hardware or a large amount of finite-element analysis (FEA) or experimental data for implementation