Current Vector Phase Based Weak Open-Circuit Fault Diagnosis of Voltage-Source Inverters

This paper presents an open-circuit fault diagnosis approach for the drive inverter system in a permanent magnet synchronous motor (PMSM). This method can detect weak faults, and extract key features based on the current vector phase. Initially, the three-phase current signal is collected as the original input, and the current vector phase is calculated. Subsequently, fault detection employs time-domain inversion techniques. A current vector residual coding (CVRC) signal is constructed based on the Park's Vector. Phase characteristics are then precisely and automatically extracted through logical operations on relational patterns. Ultimately, the fault type is located according to the different combinations of characteristic variables. Compared with the traditional methods, the proposed diagnostic technique has a simple structure and is not affected by variations in load and speed. Automatic feature extraction avoids the loss of traditional sliding window sampling information and the influence of boundary effect. The experimental results show that the method is effective and practical in the open-circuit fault diagnosis of inverters.