三相无桥功率因数校正器开路故障的快速诊断与定位策略

A Fast Open Circuit Fault Diagnosis and Location Strategy for Three-Phase Bridgeless Power Factor Corrector

为了提高三相无桥功率因数校正(PFC)工作时的可靠性与安全性,分析了其开路故障机 理和故障特征,并针对该变换器故障状态种类较多且状态样本稀疏等问题,提出一种基于近邻算 法的无桥变换器开路故障诊断策略。该策略以三相输入电流作为故障特征量,通过坐标变换和相 似性分析对各状态的已知样本进行优化,采用基于标准化曼哈顿距离的 K 最近邻算法进行故障模 式识别。仿真和实验结果显示,该诊断策略能够实现以较高采样速率对无桥变换器进行在线的实 时诊断,诊断的准确率较高,诊断速度较快,且对负载突变、谐波干扰等特殊状态具有一定鲁棒性。

In order to improve the reliability and safety of three-phase bridgeless PFC, open circuit fault mechanism and fault characteristic were analyzed. Considering the problems of numerous fault states and sparse feature samples, a novel method based on K-nearest neighbor algorithm is proposed for open circuit fault diagnosis and location. Three-phase input currents are taken as the characteristic variables, and the fault features are extracted by coordinate transformation and similarity analysis. Then the K-nearest neighbor algorithm based on normalized Manhattan distance is used to identify different fault modes. The feasibility has been verified by simulation and experimental results. The proposed method implements a high sampling rate for online real-time diagnosis with higher diagnosis accuracy and faster diagnostic time. It is also robust to some special conditions such as load mutation and harmonic interference.