بایگانی برچسب برای: synchronous machine

A Phase-Domain Synchronous Machine Model[taliem.ir]

FUZZY SLIDING MODE CONTROLLER FOR POWER SYSTEM SMIB

In this paper, a method combining fuzzy logic and sliding mode controller is proposed for the robust control of power system Single-Machine Infinite-Bus (SMIB). The aim of this study is to overcome some shortcoming of conventional power system stabilizer (CPSS), fuzzy logic power system stabilizer (FPSS) and sliding mode controllers (SMC). When conventional PSS is employed, it will result a poor performance. SMC can be used to achieve robust stability in power system. However, in the presence of large uncertainty, a higher switching gain is required, which produce higher amplitude of chattering. In this study, a direct fuzzy logic controller is designed and the sliding mode controller is added to compensate the fuzzy approximation errors. The simulation results clearly indicate the effectiveness and validity of the proposed method, in terms of convergence, time and precision.
Modeling of synchronous machines with magnetic saturation[taliem.ir]

Modeling of synchronous machines with magnetic saturation

This paper deals with a method to derive multiple models of saturated round rotor synchronous machines, based on different selections of statespace variables. By considering the machine currents and fluxes as space vectors, possible d–q models are discussed and adequately numbered. As a result several novel models are found and presented. It is shown that the total number of d–q models for a synchronous machine, with basic dampers, is 64 and therefore much higher than known. Found models are classified into three families: current, flux and mixed models. These latter, the mixed ones, constitute the major part (52) and hence offer a large choice. Regarding magnetic saturation, the paper also presents a method to account for whatever the choice of state-space variables. The approach consists of just elaborating the saturation model with winding currents as main variables and deriving all the other models from it, by ordinary mathematical manipulations. The paper emphasizes the ability of the proposed approach to develop any existing model without exception .An application to prove the validity of the method and the equivalence between all developed models is reported.
A Phase-Domain Synchronous Machine Model[taliem.ir]

A Phase-Domain Synchronous Machine Model With Constant Equivalent Conductance Matrix for EMTP-Type Solution

Interfacing machine models in either nodal analysisbased (EMTP-like) or state variable-based transient simulation programs play an important role in numerical accuracy and computational performance of the overall simulation. As an advantageous alternative to the traditional qd models, a number of advanced phase- domain (PD) and voltage-behind-reactance machine models have been recently introduced. However, the rotor-positiondependent conductance matrix in the machine–network interface complicates the use of such models in EMTP. This paper focuses on achieving constant and efficient interfacing circuit for the PD synchronous machine model. It is shown that the machine conductance matrix can be formulated into a constant submatrix plus a time-variant submatrix. Eliminating numerical saliency from the second term results in a constant conductance matrix of the proposed PD model, which is a very desirable property for the EMTP solution since the refactorization of the network conductance matrix at every time step is avoided. Case studies demonstrate that the proposed PD model represents a significant improvement over other established models used in EMTP while preserving the accuracy of the original/classical PD model.