Indian Journal of Science and Technology

Abstract

Harmonics are the major issues in Variable Frequency Drive systems. The objective of project is the analysis of harmonics in the signatures of motor current in various fault conditions of Variable Frequency Drive systems. The simulation is done on VSI fed induction motor at constant voltage/frequency and was carried out using MATLAB/ Simulink. Variable Frequency drives commonly uses “Insulated Gate Bipolar Transistor” (IGBT).To get sine wave at required frequency IGBT uses “Pulse Width Modulation” technique for simulation. Simulation of an induction was developed and by observing the current, torque and speed responses, its dynamic response was verified to set up the acceptability of the developed system. Simulation of three various fault conditions were carried out here: one IGBTs gate signal is open circuited, one IGBT in the inverter section is blown off, line to ground fault occurs in one phase of the motor terminal. The technique of frequency domain analysis is used as a method to discriminate various faulty conditions. For various faulted conditions frequency responses characteristics were analyzed and collated to setup the use of Fast Fourier Transform algorithm to distinguish the characteristics of fault. Frequency responses of three various faulty states were emphatically different and were indubitably shown.
Keywords: Fast Fourier Transform, Insulated Gate Bipolar Transistor, Pulse Width Modulation, Variable Frequency Drive