Evaluation of the Harmonics in Permanent-Magnet Synchronous Traction Motor with Low Switching Frequency Power Supply

For high-speed railway traction system, the switching frequency is limited to mitigate switching losses, which leads to the increase of harmonic components in the traction PMSM. In this paper, based on the co-simulation model, harmonics distribution of the traction PMSM for high-speed train with low switching frequency voltage-source power supply is analyzed. The co-simulations are carried out with different modulation methods. It is proved that low fundamental-carrier wave frequency ratio will lead to higher harmonics near the carrier frequency and THD performance of stator current becomes worse with the increase of the fundamental frequency of the traction PMSM. Furthermore, the saturation effect will influence the THD performance a lot.