Finite‐element calculation of electromagnetic characteristics and steady‐state stability of dual‐excited synchronous generator

Abstract

The Dual-Excited Synchronous Generator (DESG) has two sets of field windings. The magnitudes and directions of the two field currents can be regulated, so that the excitation magneto-motive force can be in any direction. The electromagnetic characteristics of the DESG may be different with those of the Traditional Synchronous Generator (TSG) for the different rotor structures of the two generators. To obtain better electromagnetic characteristics, a time-stepping finite element model (T-S FEM) of the DESG is established. The air-gap radial flux density, saturation, active and reactive power of the DESG in single-and dual-axis excitation modes are calculated and compared with those of the TSG. The electromagnetic characteristics affected by the different ratio of qaxis field current to d-axis field current are studied. On this basis, an excitation control strategy that can enhance the steady-state stability is proposed, and the steady-state stability limits with and without excitation control are calculated by the T-S FEM. A 10-kW DESG is developed to verify the correctness of the simulation results. The results show that the DESG with dual-axis excitation has better electromagnetic characteristics and stronger reactive power ability, and the steady-state stability limit of the DESG is increased obviously through the excitation control.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Optimal design of q ‐axis field winding structure of dual‐excited synchronous condenser

“…According to the finite element discrete and weighted residual method [23,24], by combining Equations ( 1) and ( 2), the electromagnetic equation can be written as follows:…”

“…According to the finite element discrete and weighted residual method [23, 24], by combining Equations () and (), the electromagnetic equation can be written as follows: $$$\boldsymbol{KA}-{\boldsymbol{C}}_{s}{\boldsymbol{I}}_{s}-{\boldsymbol{C}}_{\mathrm{f}\mathrm{d}}{i}_{\mathrm{f}\mathrm{d}}-{\boldsymbol{C}}_{\mathrm{f}\mathrm{q}}{i}_{\mathrm{f}\mathrm{q}}=\mathbf{0}$$$ …”

“…Figure24. The field currents of two field windings are supplied by the two sets of three-phase thyristor rectifier respectively.…”

A Novel Approach to Using Dual-Field Excited Synchronous Generators as Wind Power Generators

“…In the literature, DESGs have been presented as significantly better generators than conventional synchronous generators (CSGs) in strengthening the system's reliability and stability, and for their independent control of the voltage or reactive power and torque or active power [18][19][20] with DC excitation. The design and finite element analysis of DESGs with non-salient pole core rotors [21] or slot core rotors [22,23] with different excitation techniques also show that the performance of DESGs is better than that of the CSG. It has been proposed that the DESG can also be used in electric vehicles [24] with the help of a variable voltage and a variable frequency converter to overcome the present issue of the unequal diameter of wheels in vehicles.…”

Investigation of LVRT capability of wind driven dual excited synchronous generator

“…In various previous publications, DESGs have been analyzed as an important strategy for improving dynamic and steady-state stability, and increasing system reliability (Reddy et al, 2017; Xu et al, 2021). Russia in 1980s, has successively manufactured DESG with capacity from 110 up to 800 MW, and utilized them into the capital power grid with high reliability (Xu et al, 2022).…”