永磁直驱风力发电系统中两电平与三电平变流器比较

摘要

Paralleled two-level converters are widely used in low-voltage permanent magnet direct-drive wind power generation systems, while three-level converters are more suitable in medium-voltage systems. The output performances and power losses are compared between two-level and three-level converters in permanent magnet direct-drive wind power generation systems. Loss models of power device and filtering inductance are established for evaluating the power losses of the converters. Based on the operating principle of two-level and three-level converters, a practical loss calculation method is derived. Simulation and experiment results show that, comparing with two-level converter, the three-level one features lower grid-side current harmonic components and less power losses.%永磁直驱风力发电系统在低压等级下多采用两电平变流器并联运行,而在中压等级下采用三电平变流器较为合适.从系统输出性能和损耗2个方面对两电平与三电平变流器在永磁直驱风力发电系统中的应用进行了综合比较.建立了变流器功率器件和滤波电感的损耗模型,根据两电平和三电平变流器的工作原理,得出了一套实用的损耗计算公式.仿真和实验结果表明,相对于两电平变流器,三电平变流器网侧电流谐波含量较小,损耗明显降低.