In this paper, the concept and implementation of a new simple direct-torque neuro-fuzzy control (DTNFC) scheme for pulsewidth-modulation-inverter-fed induction motor drive are presented. An adaptive neuro-fuzzy inference system is applied to achieve high-performance decoupled flux and torque control. The theoretical principle and tuning procedure of this method are discussed. A 3-kW induction motor experimental system with digital signal processor TMS 320C31-based controller has been built to verify this approach. The simulation and laboratory experimental results, which illustrate the performance of the proposed scheme, are presented. Also, nomograms for controller design are given. It has been shown that the simple DTNFC is characterized by very fast torque and flux response, very-low-speed operation, and simple tuning capability. Index Terms-Direct torque control, induction motor control, neuro-fuzzy control, voltage-source pulsewidth modulation inverters. I. INTRODUCTION A DVANCED speed control of a pulsewidth-modulation (PWM)-inverter-fed drive, based on direct torque control (DTC), is receiving wide attention in the recent literature [1]-[4], [9]-[10], [14]-[16]. Fig. 1 shows two system configurations for the DTC-controlled induction motor drive. Both systems use stator flux vector and torque estimators on a PWM-inverter-fed drive. The stator flux amplitude and the electromagnetic torque are the command signals which are compared with the estimated and values respectively, giving instantaneous flux error and torque error , as shown in the figure. In the conventional scheme [Fig. 1(a)] [14], the and signals are delivered to two hysteresis comparators. The corresponding digitized output variables and the stator flux position sector create a digital word, which selects the appropriate voltage vector from the switching table. Thus, the selection table generates pulses to control the power switches in the inverter. Among the well-known disadvantages of the DTC scheme are the following [1], [3], [9], [10], [16]:

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A recursive enumerator for a function h is an algorithm f which enumerates for an input x finitely many elements including h(x). f is a k(n)-enumerator if for every input x of length n. h(x) is among the first k(n) elements enumerated by f. If there is a k(n)-enumerator for h then h is called k(n)-enumerable. We also consider enumerators which are only A-recursive for some oracle A.

The organic derivatives of phenol are classed as dangerous compounds, and their presence has been detected in surface water, bottom water, phytoplankton, zooplankton, and mussel as well as liver and muscle of fish from the Gulf of Gdańsk and in liver, muscle, and guano of gulls residing in the coastal zone of this basin. The greatest sources of bisphenol A (BPA), 4-tert-octylphenol (OP), and 4-nonylphenol (NP) were found to be the Vistula River and the water purification plant in Dębogórze. In living organisms, concentrations of BPA, OP, and NP ranged between the limit of quantification and several hundred ng g−1 dry weight (dw), and the highest concentrations were found for BPA. Prolonged alimentary exposure to BPA, OP, and NP in fish and birds was indicated by liver/muscle concentration ratios generally >1. The most influential factors on BPA and alkylphenol concentrations in the tissues of fishes and gulls were mainly diet and habitat. The study confirmed possible bioaccumulation in the food web. High BPA and NP concentrations in guano (≤2,700 and ≤300 ng g−1 dw, respectively) indicated the ability of birds to detoxify and signalled the reintroduction of these compounds to seawater. Herring, flounder, and cod from the Southern Baltic are a safe food source for human consumption because their BPA and alkylphenol contents are low.

Abstract.A Lur'e feedback control system consisting of a linear, infinite-dimensional system of boundary control in factor form and a nonlinear static sector type controller is considered. A criterion of absolute strong asymptotic stability of the null equilibrium is obtained using a quadratic form Lyapunov functional. The construction of such a functional is reduced to solving a Lur'e system of equations. A sufficient strict circle criterion of solvability of the latter is found, which is based on results by Oostveen and Curtain [Automatica 34 (1998) 953-967]. All the results are illustrated in detail by an electrical transmission line example of the distortionless loaded RLCG-type. The paper uses extensively the philosophy of reciprocal systems with bounded generating operators as recently studied and used by Curtain in (2003) [Syst.