Determination of Stray-Load Losses from Field Current Ripple of a Synchronous Machine by Field Simulation Methods

An improved three-dimensional circuit-field model of the armature of a synchronous machine with combined windings for dynamic modes of short-circuit, at supplying from a rectifier of different design is proposed. The combination of the electrical circuit, field system and spatial modeling of electromagnetic fields makes it possible allows taking into account of the effect of the design features of synchronous machines, the parameters of their windings, the nonlinearity of the electro-physical properties of materials, the effects of self-induction and mutual induction in dynamic short circuit modes. A research of the influence of the fields current ripple on the electromagnetic parameters and stray-load losses in the combined windings of the armature of a synchronous machine by field simulation method was executed for the most common rectification circuits. It is proved, that the use of single-phase bridge rectifiers violates the symmetry of the resulting voltages in the parallel phases of the armature winding of synchronous machine. For this class of synchronous machine, it is advisable to use a three-phase bridge rectifier as a field system.