Implementation of modular multilevel inverter in local trains of Mumbai

Presently DC traction system in Local Trains in Mumbai has been completely converted into AC system due to the various advantages of AC over DC. Due to the heavy load on the traction system and by using various power electronics devices the Total Harmonic Distortion (THD) is more in the traction system. Author has done the complete harmonic analysis to find the harmonic content in A.C The present Local trains in Mumbai are having capacitor bank to reduce the level of harmonic but it is found insufficient but if basic inverters are replaced by modified modular multilevel inverter the value of the THD can be reduced to the certain extent. In this paper MATLAB implementation of 5 level and 7 level has been done using PI controller. Phase disposition methods like PD, POD and APOD are used to find the performance of traction motor Harmonic analysis result is compared with the simulated results of modular multilevel inverter. This comparative study shows the benefits of using modular multilevel inverter as the harmonics values have been reduced.