One-Cycle Control of induction machine traction drive for high speed railway part I: Multi-pulse width modulation region

The configuration of a single-phase AC-DC converter plus a three-phase inverter traction system has been widely applied in high-speed railway electrical drive systems. With the single-phase power feeder, the instantaneous power is fluctuating at twice of the power line frequency, and so is the DC-link voltage. Associated with the DC-link voltage fluctuation is a severe problem, when the electric frequency of the motor is in the neighborhood of the DC link ripple frequency, the motor stator currents and torque ripples will dramatically increase when traditional multi-pulse width modulation (M-PWM) is used for inverter-motor drive system. This phenomenon may cause severe damage to the motor. In order to alleviate this problem, typically, large capacitor bank and possibly an additional large L-C filter are placed to attenuate the DC bus ripples. This solution is workable at the high price of weight, size, cost, and reliability. In this paper, a solution based on One-Cycle Control (OCC) method is proposed for the high speed railway inverter-motor drive system that does not require a large capacitor bank. The performance of OCC scheme is compared with M-PWM method, and the effectiveness and advantage of OCC scheme is confirmed by simulation tests.