Turbo-expanders are used in industries for cooling, liquefaction and also power generation. An important part of these turbines is the variable angle nozzle causing a nonlinear behavior that is not well recognized among the prime movers of the dispersed generators. In this paper, at first, the turbo expander system is evaluated in details and its nonlinear behavior is investigated. Then, the sy...

This paper presents a new intelligent agent supervisory loop based approach for dynamic system control. The scheme consists of three software agents that work in an autonomous manner for the precision control of a system that shows multiple modes and drastic parametric ‘jumps’. The first two agents are based on artificial intelligent techniques (fuzzy systems and Radial Basis Function Neural Ne...

In this paper we use the theory of L disturbance attenuation for linear H and nonlinear systems to obtain solutions to the Nonlinear Benchmark Problem NLBP proposed in the paper by Bupp et al By considering a series expansion solution to the Hamilton Jacobi Isaacs Equation associated with the nonlinear disturbance attenuation problem we obtain a series expansion solution for a nonlinear control...

This paper presents a new methodology for a weak grid is to make possible the addition of voltage source converters more effective. The controller is mainly composed of two parts, namely linear power damping and synchronizing controller and a supplementary nonlinear controller. The first part synchronizes a voltage source converter (VSC) to the grid by supplying damping and synchronizing power ...

The design of new optimal nonlinear voltage regulator for power systems is considered. In the proposed approach, the Hamilto-Jacobi-Belman (HJB), a partial differential equation, is solved using Taylor series expansion of its nonlinear terms. The performance of the proposed controller in a single-machine infinite-bus power system is simulated and the advantages of the nonlinear feedback control...

This paper tackles the problem of the speed control of an induction motor in a very general sense. On the one hand, the power of feedforward artificial neural network to capture and emulate detailed nonlinear mappings is used to implement a rotor speed estimator, and on the other hand a robust control strategy based on the sliding-mode controller type is performed. The proposed control scheme a...

Greenhouses are building structures that allow the creation of an indoor microclimate for crop development, protecting it from adverse outdoor conditions. Moreover this microclimate can be modified by artificial actuations such as heating, ventilation in order to provide the best environmental conditions. In this sense, several researchers used the optimal control and predictive control to deve...

A smart pitch control strategy for a variable speed doubly fed wind generation system is presented in this article. Nonlinear as well as linearized dynamic models of the wind system pitch controller and the doubly fed induction generator including the drive train are developed. A PI controller is employed to generate the appropriate pitch angle for varying wind speed conditions. An adaptive art...

In this paper, we use the theory of L2 disturbance attenuation for linear (H1) and nonlinear systems to obtain solutions to the Nonlinear Benchmark Problem (NLBP) proposed in the paper by Bupp et. al.1. By considering a series expansion solution to the Hamilton-Jacobi-Isaacs Equation associated with the nonlinear disturbance attenuation problem, we obtain a series expansion solution for a nonli...

The design of controllers for nonlinear systems in industry is a complex and difficult task. One approach which has shown promise for solving nonlinear control problems is the use of fuzzy logic control. This paper proposes a new method utilizing proportional–integral-derivative (PID) control as a hybrid fuzzy PID controller for nonlinear system. The salient feature of the proposed approach is ...