一种基于三维坐标识别的逆变器开路故障诊断方法

An open circuit fault diagnosis method for inverters based on spatial trajectory recognition

逆变器的安全性和可靠性对电力电子系统的稳定运行起着至关重要作用。为了实现对逆变器开关管开路故障进行快速精准的故障判定,提出一种基于三维坐标的逆变器开关管开路故障诊断方法。该方法通过建立逆变器开关管开路故障下的三相输出电流的数学模型,将输出三相电流转化为三维坐标。逆变器开关管开路故障时,逆变器的输出相电流发生畸变,三维坐标距离缩短,三维轨迹的形心坐标发生变化。通过求取三维坐标距离构建故障判断函数,正常时判断函数值为0,故障发生时,实时函数值变为1,由此可对逆变器开关管开路故障进行判断。计算三维轨迹的形心坐标,通过归一化处理,将形心坐标与参考故障定位表进行对比,对逆变器开路故障进行定位。通过半实物仿真平台进行实验验证,实验结果表明,在逆变器功率管单开关管开路故障、同相双开关管开路故障和异相双开关管开路故障实验中,均能通过构建的坐标距离函数判断故障发生,通过三维轨迹的形心坐标变化完成故障类型定位。该方法能适用于不同类型的逆变器功率开关管的断路故障诊断,能对故障快速反应并完成故障类型的诊断,具有一定的可靠性和有效性,可应用于逆变器的开路故障诊断。

The safety and reliability of inverter plays an important role in the stable operation of power electronic system. To realize fast and accurate fault diagnosis of inverter switch open circuit fault, an inverter switch open circuit fault diagnosis method based on three-dimensional coordinates was proposed in this paper. The mathematical model of the three-phase output current under the open-circuit fault of the inverter switch tube was established, and the output three-phase current was transformed into three-dimensional coordinates. When the inverter was in open-circuit fault, the output phase current of the inverter was distorted, the centroid coordinates of the three-dimensional trajectory were changed. The fault judgment function was constructed by taking the three-dimensional coordinate distance. The value of the judgment function was 0 in normal time, and the value of the real-time function became 1 when the fault occurred, so the open-circuit fault of the inverter switch tube can be judged. The centroid coordinates of the 3D trajectory were calculated and compared with the reference fault location table through normalization to locate the open circuit faults of the inverter. Finally, through the hardwarein-the-loop simulation platform for experiment, the experimental results show that in the experiments of the inverter powers tube single switch tube failure, in phase double switch tube failure, heterogeneous double switch tube failure experiment, the fault occurrence can be judged by the constructed coordinates of the distance function, and the fault types can be located through the change of centroid coordinates of three-dimensional trajectory. This method can be applied to the open circuit fault diagnosis of different types of inverter power switch tube, and can respond to the fault quickly and complete the fault diagnosis. It has certain reliability and validity, and can be applied to the open circuit fault diagnosis of inverter.