Analysis of armature inter‐turn fault in the multiphase synchronous generator‐rectifier system

Abstract

The multiphase synchronous generator-rectifier system could provide an ideal DC power source for more electric aircraft (MEA). When the inter-turn short-circuit fault occurs in phase windings of the generator, a large short-circuit current would be introduced inside the armature windings, which could cause severe damages to the system for overheat in the windings and irons as well as huge electromagnetic forces on the end coils. To improve the reliability of the MEA, this study researches on the inter-turn fault of the multiphase generator-rectifier system including the theoretical analysis, numerical simulation and experiment verification. A 12-phase system is taken, for example, and a multi-loop mathematical model is built up to calculate all voltages and currents in the multiphase synchronous generator-rectifier system with armature inter-turn fault. Many factors are thoroughly considered in the model including the location and short turns of fault, space harmonics of the airgap magnetic field and the changing circuit topology of the system. Moreover, the mathematical model is verified by fault experiment results. Moreover, the electric characteristics of the fault are summarised, which could provide a quantitative basis for early detection of the inter-turn faults in the multiphase generator-rectifier system.

Diode rectifier configurations with a multiphase synchronous generator

“…Five sets of three-phase, star, FP, series-stacked rectifiers are shown to provide the best option in terms of generator copper losses, peak power capability and power factor, although other options provide lower DC voltage ripple. This study has specifically addressed healthy performance, supplementing [20,22] on fault tolerance, giving new insight that the use of split-phase GRS to improve fault tolerance can also give steady-state performance benefits.…”

Multi‐loop model for fractional pole‐path ratio synchronous generators with stator winding internal faults

“…Taking these coils as examples, the inductance parameters were calculated using the method proposed in this paper and the method in [21–24]. For the convenience of analysis and comparison, the inductance calculation method in [21–24] is called the existing calculation method, which cannot consider the effect of changes of coil pitch on inductance parameters. The method proposed in this paper is called the improved calculation method.…”

“…In [22], an improved multi‐loop model considering the effect of the distributed capacitances is proposed, and the model is more accurate in simulating the windings to ground faults. In [23, 24], the model of multiphase synchronous generators with internal faults is established by the multi‐loop method.…”

“…It should be noted that in [21–24] when the mutual inductance parameters of stator coils are calculated based on the multi‐loop method, the pitch of stator coils should be consistent. However, due to the special structure of the fractional pole‐path ratio windings, the pitch of stator coils is not always equal.…”

“…However, due to the special structure of the fractional pole‐path ratio windings, the pitch of stator coils is not always equal. Obviously, the multi‐loop model proposed in [21–24] is not suited to analyse the internal faults of fractional pole‐path ratio synchronous generators.…”