Paralleled Inverters to Drive Double Dual-Three-Phase Induction Motors With Common-Mode Voltage Mitigation for Traction Application

For railway traction application by induction motor drives, common-mode (CM) leakage current generated by traction inverter is a big threat. This article introduces the technology of paralleled inverters to drive double dual-three-phase induction motors for traction application. The pulsewidth modulation (PWM) in the paralleled inverters can eliminate the CM voltage caused by PWM of the inverters and to mitigate the CM leakage current in the dual motors. The design and analysis of the dual-three-phase induction machine is introduced at first. Through different terminal connections, dual three-phase motors can be connected in the same phase and in the reverse phase. Then, the paralleled inverters with zero CM PWM are used to drive the double motors in traction mode for both of the two kinds of windings. Considering the deadtime effect, the zero CM PWM for phase-reversed windings can obtain better CM elimination effect than the case with phase-aligned windings. At the same time, the Zero CM (ZCM) algorithm can be well combined with synchronous modulation to meet the needs of the actual railway traction system. Simulation and experimental results are provided to validate that with the proposed method, common mode current of the double induction motors can be reduced significantly and the traction performance can be obtained.