Modeling and Diagnosis of Induction Machines Operating under Open-Phase Fault

This paper presents a new approach for the modeling and diagnosis of the induction machines (IM) operation under open-phase fault. This fault condition is considered as the most serious one since it produces significant pulsating torque, significant losses, vibration, noise and an excessive heating of the machine. Moreover, it conducts to interturn fault according to the excessive heating of stator windings. As an early detection of open-phase fault is mandatory, particularly attention has been given in the literature to the modeling and diagnosis of IM operating under this faulty condition. In this context, we suggest a new approach for the modeling of the IM operation under open-phase fault using a state model. In asymmetrical star connected IM, the common point voltage differs from zero. As a result, the stator voltages differ from the network simple voltages. For this reason, we use line to line voltages, which are imposed by the network, as inputs in the state model of the machine. Several advantages of the proposed approach can be noted. It can be extended for the analysis of faulty induction machines. In addition, the space and time harmonics can be taken into account. Moreover, magnetic saturation, skin effect, skewed rotor and slotting effects can be integrated in the calculation of the machine inductances. It also offers a good compromise between modeling precision and simulation time. With this approach, open-phase signatures can be extracted on mechanical speed, electromagnetic torque, machine common point voltage, stator currents and fluxes. The obtained results show good agreement with other results which have been obtained using other approaches such as finite elements and symmetrical components methods. The contribution of this work is that the induction machine state equations, machine currents, machine common point voltage are established for open-phase fault condition and a state model is derived for the analysis of the IM operating under this faulty condition. Simulation and experimental results shows the consistency and the applicability of the proposed approach for the modeling of IM operation under Open-phase fault comparatively with previous works.