基于模糊逻辑的三电平T型逆变器故障诊断研究

Research of Fault Diagnosis of Three-level T-type Inverter Based on Fuzzy Logic

三电平T型逆变器由于具有较低损耗、较少元件数量和较高耐压等级而被广泛应用.但其功率开关管因其高频工作,容易出现故障.发生功率管开路故障后,交流侧输出的畸变电流会对电网产生损害.因此,其功率管的开路故障诊断显得尤为重要.本文提出一种模糊逻辑方法诊断三电平T型逆变器功率管开路故障.该方法对三相电流值求均方根,用来判断功率管开路故障是否发生.如果发生故障,将逆变器输出的三相电流平均值模糊化、模糊推理、反模糊化后实现故障定位.根据建立的适当模糊规则,可以对三电平T型逆变器功率管单管、双管开路故障精确定位.

Three level T-type inverter is widely used because of its low loss,less number of components and high tolerant voltage level.However,the power switch of three level T-type inverter is prone to failure because of its high-frequency operation.After the open circuit fault of power tube in three level T-type inverter,the distorted current output at the AC side will damage the power grid.Therefore,the open circuit fault diagnosis of power tube is particularly important.A fuzzy logic method is proposed to diagnose the open circuit fault of power tube in three-level T-type inverter.Firstly,the root mean square of three-phase current value is obtained to judge whether the open circuit fault of power tube occurs or not.In case of the fault occurrence,the average value of three-phase current output is processed by fuzzification,fuzzy reasoning and anti-fuzzification to realize the fault location.It appropriates for the establishment of fuzzy rules,the open circuit faults of single and double power tubes in three-level T-type inverter can be located accurately.