大型同步电机交交变频调速系统对电网的谐波影响分析

针对热连轧机组中同步电动机主传动的交-交变频调速系统，定量分析了同步电机负载经由交交变频器对变压器供电网侧产生的谐波影响.分别对不同的负载参数、变压器原副边电感量和变流装置的进线电抗器参数的情况进行了仿真分析.同时，对大型多组交交变频器移相组合式供电进行了数据移位方式仿真.并且对交-交变频器和交-直-交变频器所产生的谐波干扰进行了对比分析.仿真结果表明调节变压器原副边电感量再结合移相组合式供电的方法可以有效地降低大型同步机负载对供电网侧的谐波干扰，并使得总谐波率在各相中分布趋向均衡.

Harmonic Analysis of Power Supply Net Side with Large Synchronous Frequency Speed Drive System

For AC to AC variable frequency speed drive system of synchronous motors applied in hot strip continuous mills,the harmonic impact on power supply net side is analyzed in detail by advanced simulation approach.Variety of situations have been studied by changing parameters of different parts in the synchronous frequency speed drive system,such as internal inductance of original/secondary sides of the transformers,external line commutating reactors and several kinds of synchronous motors with different resistance and inductance.An approach of power supply is proposed that adopting multi-group AC-AC inverters with incremental-shifting phase module to supply power.A comparative analysis of harmonic interference between the AC-AC inverter and AC-DC-AC inverter is given.Simulation results show that the approach combination regulating transformer inductance with the incremental-shifting phase modular power supply can effectively reduce harmonic interference and make the total harmonic distribution tend to be balanced in three phases.