Performance Comparison Of Multipulse Converter And Z- Source Inverter Duos Feeding DTC Induction Motor Drive

Abstract

Non-linear loads like Direct Torque Control (DTC) induction motor drive are a major source of harmonics in the power system. To overcome the problem of harmonics, multipulse converters are widely used. This thesis highlights the performance comparison of different multipulse converters which have been simulated in MATLAB/SIMULINK. Performance comparison of the 6-pulse, 12-pulse and 18-pulse converters feeding R-load has been performed. The phase shift in the converters is achieved by using zig-zag phase shifting transformers. The Total Harmonic Distortion (THD) in input current and input voltage along with ripple content in the output voltage and output current have been measured and their corresponding waveforms have been observed. Also, performance comparison of 6-pulse, 12-pulse and 18-pulse converter with maximum constant boost control technique based Z-source inverter, in order to form duos feeding DTC induction motor drive have been performed. The results obtained with a multipulse converter and Z-source inverter duos have been compared with those obtained with the multipulse converter and traditional inverter duos. It has been observed that duo consisting of Zsource inverter provides better results in terms of THD in input voltage and input current. Zsource inverter improves the reliability of the system. It also reduces noise and electromagnetic interference. Simulation of 14-pulse converter which is a non-integer multiple of six, and its integral multiples has been carried out. It has been found that as the pulse number of a converter increases, THD in input voltage and input current along with ripple content in the output voltage and output current is decreased.