Design and Development of a 36-Pulse AC-DC Converter for Vector Controlled Induction Motor Drive

In this paper, an autotransformer based 36-pulse AC-DC converter fed vector controlled induction motor drives (VCIMD's) is presented for reduction of harmonic-currents. A 36-pulse converter is realized using a specially designed autotransformer and two 18-pulse diode bridge rectifiers. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed AC-DC converter. A set of power quality indices on input AC mains and on DC bus for a VCIMD fed from 6-pulse and 18-pulse AC-DC converters are also given to compare their performance. It is observed that input current total harmonic distortion (THD) less than 5% is possible with the proposed topology at varying-loads. A laboratory prototype of this 36-pulse AC-DC converter is developed and test results are presented to validate the design and simulation model. It improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.