基于直流侧电流检测的逆变器开路故障诊断方法

针对变频驱动系统中的逆变器开关管开路故障，应用开关函数的双傅里叶变换技术，分析逆变器的直流侧电流在正常运行、单管开路故障及一相开路故障时的频谱：逆变器正常运行时，其直流侧电流频谱的低频部分只包含直流成分；逆变器单管开路故障时，其直流侧电流频谱的低频部分会出现调制信号的频率成分；逆变器一相开路故障时，其直流侧电流频谱的低频部分除了直流成分外，还会出现调制信号的二次谐波成分。通过检测直流侧电流的频率成分就可实现逆变器单管开路故障及一相开路故障的故障诊断。实验结果验证了该方法的正确性和有效性。

Invester Fault Diagnose Based on Detecting DC Side Current

For diagnosing the inverters transistor base drive open fault in variable frequency drive system, the frequency spectrum in normal, open fault of one transistor and open fault of two transistors in one phase is analyzed by introducing the double Fourier transfor of the switch function: The low frequency spectrum of DC side current contains DC component only when the inverter runs in normal; The low frequency spectrum of DC side current contains the DC component and some harmonic of modulation signal when one transistor is open; The low frequency spectrum of DC side current contains the DC component and the second harmonic of modulation signal only when two transistors in one phase are open. The open fault of one transistor and open fault of two transistors in one phase can be examined by detecting the frequency components of DC side current. Theoretical analysis is verified by esperinent results.