Analysis on Bidirectional Multilevel Converter for Electric Locomotive

Abstract

Nowadays, power converters have been mainly introduced to solve the difficulty where the semiconductor switches cannot connect directly to the high-speed traction drives. newlineThe difficulty can be overcome by the multilevel converters by using high-power switches with high-speed switching techniques, which gives a great flexibility for the traction motors when compared with the conventional converter. Multilevel converter has a high-power rating which is used for high-speed control applications. newlineIn the past few years, the new topologies for multilevel converter have been developed. The aim of this research is to deeply evaluate and investigate the converter to achieve the high switching speed with the increased level of the output voltage and to achieve IEEE standard and Railway standard total harmonic distortion below 5% in the output voltage and the output current for the three-phase AC induction motor in the locomotives. Sinusoidal pulse width modulation (SPWM) technique is used and the pulse was controlled by the controller which is the artificial intelligence process. newlineDiode-Clamped Multilevel Converter (DCMC), Flying Capacitor Multilevel Converter (FCMC) and Cascaded H-Bridge Multilevel Converter (CH-BMC) is designed with three-phase induction motor for locomotives using MATLAB/Simulink. During running conditions, when the induction motor operates above the synchronous speed, the bidirectional converter converts the voltage and this voltage is newlineix newlinecalled regenerative voltage by the regenerative braking approach where the regenerated DC voltage is stored in the battery where it can be used for the DC circuits in the locomotives. The switching technique in this research helps to reach the perfect harmonic balance and also to maintain the circuits in feasible cost. newlineThe closed loop system is simulated using PID and ANFIS controller, to control the speed of the induction motor for the locomotive to reduce the electromagnetic torque and also the Total Harmonic Distortion (THD) is reduced.