Three-Phase Inverters Open-Circuit Fault Diagnostic Based on Voltage Residual

Aiming at the open circuit fault diagnosis of three-phase inverters, a fault diagnosis method based on residual theory with dynamic reference quantity is proposed. Using the existing phase voltage sampling signal of the inverter closed-loop control system, the phase voltage sampling signal with one period delay is used as a dynamic reference, and the voltage residual waveform is obtained by comparing the dynamic reference voltage signal with the current phase voltage signal. By setting a reasonable fault detection threshold, the voltage residual waveform can be used to accurately diagnose the open circuit fault of the inverters. Simulation results show that this method has the ability to resist unbalanced load and load mutation interference, and the diagnosis time is less than one fundamental wave cycle.