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This paper presents the modeling and steady-state performance of a novel dual-winding reluctance generator (DWRG) that uses a multiple-barrier (MB) rotor. A simple math-ematical model was developed, and the effects of external parameters (speed, field current, and load) on the steady-state performance were analyzed. Experimental results conducted on a prototype machine were also provided to justify the theoretical approach and performance calculations. The developed model takes into account the magnetic saturation and core loss and enables a quantitative prediction of load characteristics from the no-load test data. Index Terms--Core loss, dual winding, equivalent circuit, magnetic saturation, multiple-barrier (MB) rotor, reluctance generator.

Doubly fed generators have been used as adjustable-speed pumped-storage generator motors and wind turbine generators. Accurate determination of field currents and reactances is important for the design of these machines. We propose a calculation method to obtain the field currents and reactances of machines with rotor duct pieces under any steady-state balanced load condition. The method links two-dimensional static finite-element analysis (FEA) with an approximate calculation to consider three-dimensional (3-D) skin effect in the duct pieces. Its advantage is that the computational time is much smaller than 3-D transient FEA when the slip frequency is not zero. The method will contribute to improvement of the design of doubly fed generators with rotor duct pieces. It was applied to a 395 MVA machine, and the calculated field currents agreed well with the measurements. Variation in the reactances due to saturation is also discussed. Index Terms--Adjustable-speed pumped storage system, cross magnetization, finite-element method, inductance, skin effect, slip.

A simple magnetic circuit of salient-pole synchronous machines is presented. A method for calculating steady-state electrical performances using the circuit is described. Magnetic saturation including the cross-magnetizing phenomenon is considered in the method. The saturated reactances, field currents, and load angles are calculated easily from the method without much computational effort as compared with the finite element method. Despite the simplicity of the magnetic circuit, the calculated reactances at various load conditions using the method are close to the measured and FEM values. Index Terms--Cross-magnetization, magnetic circuit, magnetic saturation, reactances, synchronous machines.

It is important to understand the relationship between leakage flux distributions and machine characteristics for better design of synchronous machines. This paper presents a calculation method for leakage inductances of saturated salient-pole machines with damper circuits. All leakage inductances are divided into the self-leakage, gap leakage, and winding-differential leakage inductances. The leakage inductances correspond directly to the leakage flux distributions in the machines. Cross-magnetizing inductances are also calculated. The method is applied to a 300-MVA class generator. The relationship between the winding distributions, flux distributions, saturation, and inductances is discussed. Weak magnetic influence of the damper circuits on the armature in the d-axis is quantitatively illustrated through values of the winding-differential leakage inductances. The cross- magnetizing inductances, except for the d-axis damper circuits, are relatively large. Variations of the armature self-leakage inductances with saturation are small, and variations of the field and damper self-leakage inductances are larger. Index Terms--Cross-magnetizing effect, damper circuits, finite element methods, leakage inductances, magnetic saturation, salient-pole synchronous machines.