Fault-tolerant Operation Strategy for Claw-pole Generators with Stator Turn-to-turn Short Circuits

The stator turn-to-turn short circuit is an important type of fault in automotive claw-pole generators (CPGs). If left unprotected, the fault may develop into catastrophic stator winding failures or stator core failures. This paper proposes a fault-tolerant operation strategy for CPGs with stator turn-toturn short circuits. A dynamic model of the CPG with stator turn faults is presented in this paper to analyze how the fault would interact with the connected battery and the static full-bridge rectifier, and how it would affect the generator's output voltage and current. The derived model, when implemented in its equivalent-circuit form, is able to accurately determine the fault current from the observed fault signature. Using a database generated by this model, an optimal fault-tolerant operation strategy is proposed to prevent the stator winding insulation from further thermal degradation while preserving as much as possible the limp-home capability of the automobile. Although the method is originally proposed for CPGs, it is also applicable to other poly-phase AC generators with a DC link rectifier.