The aim of this paper is to use the combination of Reproducing kernel Hilbert space method (RKHSM) and fractional differential transform method (FDTM) to solve the linear and nonlinear fuzzy impulsive fractional differential equations. Finding the numerical solutions of this class of equations are a difficult topic to analyze. In this study, convergence analysis, estimations error and bounds errors are discussed in detail under some hypotheses which provide the theoretical basis of the proposed algorithm. Some numerical examples indicate that this method is an efficient one to solve the mentioned equations.

No abstract

This paper deals with design and stability of a new nonlinear fuzzy state feedback controller for HVDC systems. A novel simplified nonlinear dynamic model is developed for HVDC system that can be used to design the controller. The proposed nonlinear dynamic model decomposes into several linear systems around its important equilibrium points. These local linear models describe the plant dynamical behavior at its different operating points. The proposed controller is used in the control loops of the HVDC system. The simulation is carried out based on the Cigré benchmark model. Simulation results show improvement of overall AC/DC/AC system performance when severe faults occur, compared to the conventional controller. Also, the stable behavior of a very weak AC/DC system (SCR<2) with proposed controller is very significant when a sudden change in current order and/or a switched reduction in ESCR is applied. The same situation with conventional control brings the system into unstable region.

In this work, the Adomian Decomposition Method (ADM) is applied to compute the Fourier transform (FT) of functions on R. The basic properties of the Fourier transform are again obtained by ADM and examples assuring the applicability of ADM are presented.

No abstract