Fault Analysis of Inter-Turn Short Circuit of Switched Reluctance Motor for EV Application

Switched Reluctance Motor (SRM) is a best candidate for propelling an Electric Vehicle (EV) because of its simple and rugged construction, and most importantly due to the absence of permanent magnets. Even though these motors are fault tolerant in terms of motor-body fault, they are subjected to inter-turn fault. Diagnosis of this fault is very much important for reliable operation of SRM. This paper discusses the fault analysis techniques for the diagnosis of inter-turn fault. The mathematical modeling of a 6 phase, 12/10 pole, 850 W, 72 V, 9600 rpm SRM has been formulated. Two types of fault analysis techniques are mainly discussed (i) Partially shorting one phase winding (ii) By injecting a high frequency voltage signal to the non-operating phase. In first type, different scenarios including one-pole fault and two-pole fault are analyzed to study the effect on the motor parameters especially on the flux density distribution and on the motor inductance. In the second type, effect of adding a high frequency voltage signal in the phase current is analyzed. Finite element analysis (FEA) using ANSYS Maxwell is used to analyze these fault techniques, and the simulation results are presented. These techniques shall be utilized in the detection and diagnosis of the inter-turn fault in SRM.