Performance Estimation of an Inverter Fed Three Phase Induction Motor at Reduced Flux Condition

A sensor-less, low cost technique for parameter estimation under reduced flux condition is presented here for better evaluation of losses and performance of inverter fed induction motors in field weakening mode. For this purpose, transient voltage and current data have been recorded with a digital storage oscilloscope. From these measured inverter output voltage and current data, equivalent circuit parameters, losses and inertia of the machine have been estimated using particle swarm optimization. This estimation has been carried out considering dynamic model of a three-phase induction motor. Machine parameters have also been determined from classical dc resistance test, no load test and blocked rotor test as per IEEE guideline. The estimated parameters have been compared with the parameters obtained from the abovementioned tests. Performance characteristics have also been predicted for both estimated and experimentally obtained parameters and compared with the measured values. The above-mentioned procedure has also been carried out for sinusoidal supply voltage fed to the same induction motor. The comparative study has been presented in this paper.