E-type asymmetric multilevel inverter based transformer less traction drive

Abstract

To overcome the limitations of conventional multilevel inverter such as of more no. of power semiconductor switches, large no. of capacitors, more switching loss etc., a new topology of Envelope type (E-type) MLI is used. This E-type Module has some preferable features like reduced no. of components and low switching frequency. This E-type asymmetric converter uses four unequal DC sources and ten switches to generate 13 level of output voltage. SHE modulation technique is used to achieve high quality output voltage with low harmonic content. This E-type converter configuration will be used in transformer less traction drive. Nowadays Induction motors are used as electric drives for most of the electric railways. A transformer less connection is used for feeding Induction motor. This converter-inverter configuration will convert single phase AC voltage to DC and again this DC voltage will be converted into three phase AC. The output of the E-type Multi level inverter will be used to drive the Induction motors.