Research on multiple topology and modulation strategy of large capacity traction inverter for high speed maglev train

Considering the characteristics of high capacity and high output voltage of traction inverter for high-speed maglev train, this paper presents a multi-unit module series topology, in which the unit module adopts single-phase three-level full-bridge topology. Compared with the two-level topology, the voltage stress of each switch in the three-level topology is only half of the DC bus voltage, so the corresponding DC bus voltage can be doubled. Besides, the use of multiple series structure can increase the output voltage and capacity. Meanwhile, in this paper, the Third Harmonic Injection Pulse Width Modulation (THIPWM) algorithm based on carrier phase-shifting technology is adopted to improve the output capability of the inverter and reduce the harmonic distortion of the output waveform. In this paper, the load is a long stator linear synchronous motor (LSM), and the electrical parameters of the motor are obtained by ANSYS simulation software. The simulation verifies the superiority of the topology and modulation algorithm.