Experimental Investigation On The Distribution Of Voltage At The Stator Winding

Abstract

The application of inverter fed induction motors in industrial sector is growing fast due to its ability to line with smooth speed control.  However, the most common problem is the appearance of the overvoltage at the motor terminal that leads to a reduction in the life time of the motor. The characteristics impedance difference between cable and induction motor along with the fast switching devices in the motor drive cause high voltage at the terminal of motor.This paper describes investigation of the over voltages based on cable length and rise time through both experiment and simulation. Further, the study of overvoltage is extended to multilevel inverter.Moreover,the distribution of overvoltage across the windings is investigated based on the lumped parameter model.  The simulation and experimental results indicated that the voltage stress is more on the first few turns compared to the consecutive turns. Hence, the probability of premature failure of the first turn insulation is very high due to this non-uniform distribution of overvoltage across the winding. Simulation results have been validated using the hardware results