The influence of non-sinusoidal voltage sources on the steady state performance of different NEMA Designs of IMs

Abstract

Voltage distortion has become one of the most common power quality problems in industrial applications, which has gained a great deal of attention in recent years because of the widespread usage of non-linear loads. Three-phase induction motors are widely used and one of the factors that confirm the reduction of their performance is the presence of harmonics in their volt age supply. In this paper, the impact of non-sinusoidal supply voltages on the steady-state performance of different NEMA designs of squirrel cage induction motors (SCIMs) is presented. It presents the analytical modeling based on the equivalent circuit taki ng into consideration the skin effect impedance that incorporates the skin effect on the rotor bars, which is used to investigate the motor performance under such conditions. The importance of this study is that it compares all NEMA designs in terms of electromagnetic torque, efficiency, losses, power factor, stator and rotor currents, and derating factor under a distorted supply voltage that is polluted by the most significant odd harmonic orders at adjustable levels in the range of (0 25) % of THDv %. The obtained results are compared and validated with the system employed by using MATLAB/Simulink software. The simulation and the analytical model results have shown good accuracy.