The rising of single-phase distributed generators and imbalanced loads in the electrical power grid can cause the three phases voltage to unbalance, causing in risen losses and overheating in motors. As a consequence of the growing usage of electronic equipment and non-linear load, the waveform of the voltage source of the electrical system is becoming distorted and variations appear among the phases. This work explores the negative impacts of imbalanced of 10 HP three phase induction motor squirrel-cage fed by three phase IGBT inverter at full load. The drive system has been designed and simulated by MATLAB/Simulink. The inverter switches are controlled by a pulse controller, which consists of two level pulse width modulation (PWM). The results represent the effects on the performance of the motor. The results of the Simulation show the negative impacts of imbalanced non-sinusoidal voltages which are higher than the case of balanced non-sinusoidal voltages. Also, the computation of voltage unbalance factor (VUF) depending on positive and negative sequence components are considered.

Voltage unbalance is an adverse global phenomenon impacting three-phase induction motor output. Three-phase source voltage may become imbalanced in a variety of respects, while a balanced system preserves stable voltage magnitude and angles in three phases, but a completely balanced state is difficult to get. Imbalanced cases may differ in multiple ranges which may practically affect the motor. So, this work is an effort to analyze the operations with appropriate propositions. The output of a three-phase induction motor working with an imbalanced supply grid, MATLAB/SIMULINK is further used for simulation purposes and programming based on the asymmetrical component approach is adopted. A new design for system rerating is being proposed. As a case study, a 10 HP three-phase induction motor was used. The findings of the study show that to determine the output of the induction motor, positive voltage series must be respected under the voltage unbalance factor (VUF) or proportion voltage unbalance index with six various voltage magnitude imbalance conditions, the copper losses of three-phase induction motors were calculated under full load conditions by simulation. So, the qualified percentage change in total copper losses for the motor operating under imbalanced and balanced voltages was determined.