非侵入式逆变器功率管开路故障诊断方法

A Non-Intrusive Diagnostic Technique for Open-Circuited Faults of Inverters

针对逆变器中较高的开关管故障率,该文提出一种非侵入式的逆变器开路故障在线诊断与定位方法。提出适合三相逆变电路的故障特征参数预处理方法,处理逆变器已有传感器所采集的特征信号;建立输出线电压包络线函数和诊断函数,利用线电压包络线和故障参数特征,精确定位开关管开路故障,为逆变系统的容错控制和快速检修提供可靠故障信息。该方法无需采集逆变器控制信号,与逆变控制方式无关;无需增加额外的传感器,受负载影响小,适应性强;采用简单的硬件结构,诊断系统成本低,可靠性高,定位时间短;最后,通过搭建实验样机验证了所提出的理论,通过样机试验分析了负载突变、不同控制频率和不同故障时刻对所提出方法的影响,证明了方法的有效性和适应性。

In view of the relatively high failure rate of IGBT in inverters, a non-intrusive online open circuit fault diagnosis method is proposed in this paper. A proper preprocessing technique for fault characteristic parameters is proposed. A line to line output voltage envelop function is built. All the switches＇ open circuited faults can be diagnosis and located precisely by using the fault characteristic parameters and the line to line output voltage envelop. So the reliability of inverter is enhanced and the maintenance process is speed up. The proposed method is implemented with simple hardware to achieve the diagnosis and locating algorithm, which has advantages of low cost, high reliability and speed. In addition, no extra sensors are needed as well as the IGBT trigger signals, so the independence of new diagnosis method to both inverter control strategy and load conditions are guaranteed. An experimental prototype is built. Several test are proceeded to analysis the influence of load variation, different control strategies and fault occurrence time on the proposed method. The results validate the proposed method and indicate that the method has great adaptability.