基于开关状态的三电平NPC整流器开路故障诊断

Open-circuit fault diagnosis of three-level NPC rectifier based on switching states

为了降低三电平中点钳位型(NPC)整流器故障诊断算法的复杂度和成本,本文提出基于开关状态的开关开路故障诊断方法。首先,选取某些开关状态在半个电流周期的累计值作为诊断变量,并结合自适应阈值及电流相位实现故障桥臂的检测。其次,执行基于无功电流注入的外开关故障容错控制并对阈值进行更新。最后,在容错期间基于诊断变量的变化情况,实现故障开关的定位。所提出的方法能够同时实现单和双开关开路故障诊断,而无需额外的传感器以及复杂的计算和诊断规则,具有实现简单和成本低的优点。实验结果验证了所提出方法的有效性和鲁棒性。

In order to reduce the diagnostic complexity and cost of the three-level neutral-point-clamped(NPC)rectifier,a fault diagnosis method for the open-circuit fault of power switches was proposed.This method was based on the characteristics of switching states.Firstly,the cumulative values of some switching states in half a current cycle were selected as the diagnostic variables,which were combined with the self-adaptive threshold and the phase of currents to realize the faulty bridge arm detection.Then,the outerswitch fault-tolerant control based on reactive current injection was implemented and the threshold was updated.Finally,according to the change of diagnostic variables,the faulty switch was located during fault-tolerant process.The proposed method can realize both singleswitch and double-switch open-circuit fault diagnosis without additional sensors,complicated calculations and diagnostic rules.It has the advantages of simple implementation and low cost.The experimental results verify the effectiveness and robustness of the proposed method.