An Efficiency Estimation Method for Inverter Fed Induction Motors

This paper presents an efficiency estimation method for inverter-fed induction motors using a rotor currents observer. A recursive linear combination of stator currents and previous rotor currents' values are used to calculate the currents. The deep-bar model machine parameters are estimated from a no-load motor start-up transient instantaneous impedance. During the efficiency estimation process, the algorithm requires the stator current measurement and the machine parameters. The proposed methodology was experimentally validated using an induction motor with a load ranged between 30% to 105%. The results are compared with the IEC600-34-2-2013-TS, with a deviation of 0.5% for the worst case. This performance demonstrates the application of the methodology in in-situ applications.