Operating characteristic analysis of induction machine with open phase fault under back-to-back voltage-fed SPWM frequency converter power supply

On the basis of establishing mathematical model of induction machine, the simplifying assumption of two-dimensional plane finite element model was proposed, and Dirichlet and main boundary conditions were defined. The speed governing of induction machine was realized using back-to-back voltage-fed frequency converter. The continuous output direct voltage value of three-phase non-controlled rectifier circuit was calculated, and the parameter setting of carrier signal and modulating wave signal in SPWM inverter circuit was explained. The operation status model of induction machine with open phase fault was proposed based equivalent circuit method and field-circuit coupled method. We analyzed the relation between open phase fault and rated operating phase current, the rotation change, and the variations of torque and magnetic linkage. Through comparison, it can be known that the simulation results of field-circuit coupled method were more accurate, and the curve was more smooth. Although the simulation duration of field-circuit coupled method was longer, it provided theoretical basis for motor fault diagnosis and play an guiding role for operation analysis of induction machine.