【摘要】 三电平拓扑由于等效开关频率高,可以降低滤波器成本,在新能源发电及其他场合得到了广泛应用。由于半导体器件及驱动的个体差异,器件的开通及关断特性并不是严格一致,这就给"Ⅰ型"三电平变流器的运行带来了风险。在此首先提出了兼容电网故障穿越(FRT)逻辑的变流器过流故障判断逻辑,可以在保护变流器的同时满足电网FRT要求。然后通过分析不同情况下的"封波过程",说明了"Ⅰ型"三电平拓扑应该先关断外管再关断内管,结合风电变流器的FRT,通过分析FRT下的"再起机"过程,说明了"Ⅰ型"三电平拓扑在"再起机"时应该先开通内管。实验验证了所提过流故障判断逻辑及发波策略的有效性。更多还原

【Abstract】 Three-level topology is widely used in new energy generation and other fields because of its high equivalent switching frequency and low filter cost.Because of the individual difference between the semiconductor device and the driver,the switch-on and switch-off characteristics of the devices are not exactly the same,which brings the risk to the operation of the "type Ⅰ" three-level converter.An over-current fault diagnosis logic compatible with fault ride through(FRT) logic is proposed,which can meet the FRT requirements while protecting the converter.Then,by analyzing the "wave sealing process" under different conditions,it is shown that the "type Ⅰ" three-level topology should first turn off the outer tube and then turn off the inner tube,it is explained that the inner tube should be opened when the "type Ⅰ" three-level topology is "restarted".The overcurrent fault diagnosis logic and the wave generation strategy are verified by experiments.更多还原