T型三电平变流器开路故障容错控制研究

Research on Open-circuit Fault Tolerant Control of T-type Three-level Converter

针对T型三电平变流器功率器件开路故障问题,提出了一种基于载波调制的容错控制策略。通过分析开路故障状态下三电平变流器的换流路径,研究系统工况对于故障影响范围及容错控制实施的影响。在此基础之上通过调制波同步补偿和异步补偿的方法,在保证线电压输出不变性的前提下实施有效的容错控制。该控制策略相较于传统基于空间矢量调制的容错控制策略省略了无效空间矢量定位和纷杂的矢量替换等实施环节,大大降低了容错控制的复杂度,并且能够根据系统的运行工况实时调整容错控制的实施范围,仿真和实验结果表明所提控制策略的正确性和有效性。

For open circuit fault of the T-type three-level converter power device,a fault tolerant control strategy based on carrierbased modulation is proposed.By analyzing the commutation path of the three-level converter in the fault state,the influence of the system operating conditions on the fault range and the implementation of fault tolerant control is studied.On this basis,by modulation wave synchronous and asynchronous compensation,effective fault tolerant control is implemented under the invariance of line voltage.Compared with the fault tolerant strategy based on space vector modulation,the proposed method omits implementations of invalid vector positioning and vector replacement,which greatly reduces the complexity of the fault tolerant control.In addition,the proposed method can adjust implementation scope of fault tolerant according to the system operating state conditions.Simulation and experimental results show the correctness and effectiveness of the proposed control strategy.