O emisiji buke iz izmjeničnih pogona upravljanih pulsno-širinskom modulacijom

The paper presents and analyses the experimental acoustic noise of AC motors controlled by drives using different PWM techniques. After a discussion upon PWM methods concerning noise reduction, measure based comparisons are interpreted. Five criteria are taken into account: motor type, motor power, rotor speed, switching frequency and PWM method.U radu se izlaže eksperimentalna analiza buke emitirane iz izmjeničnih pogona upravljanih različitim postupcima pulsno-širinske modulacije (PWM). Nakon izlaganja utjecaja izbora PWM postupka na stupanj redukcije buke, uspoređeni su i interpretirani mjerni rezultati. Uzeto je u obzir pet kriterija: tip motora, snaga motora, brzina vrtnje, sklopna frekvencija i tip PWM postupka

Représentations Systèmes Multi-Machines (SMM) de machines polyphasées

Cet article présente le principe de décomposition de machines polyphasées en machines fictives monophasée et diphasées non couplées magnétiquement. Après la description de la méthodologie de décomposition SMM (Systèmes Multimachines Multiconvertisseurs), deux cas sont étudiés. Une machine synchrone pentaphasée, est d'abord analysée avec son modèle de machines équivalentes. Un second cas plus original est ensuite étudié : deux machines pentaphasées connectées en série et alimentées par un onduleur 5 bras.This paper presents the equivalence of multi-phase machines with a set a of 1-phase and 2-phase machines with no magnetic couplings. Two cases are then studied. First, a 5-phase machine supplied by a Voltage Source Inverter(VSI) is analyzed. Then, a model is established for a single 5-leg VSI supplying two 5-phase machines whose windings are connected in series

Bourdieusian Reflections on Language: Unavoidable Conditions of the Real Speech Situation

The main purpose of this paper is to shed light on Pierre Bourdieu’s conception of language. Although he has dedicated a significant part of his work to the study of language and even though his analysis of language has been extensively discussed in the literature, almost no attention has been paid to the factthat Bourdieu’s account of language is based on a number of ontological presuppositions, that is, on a set of universal assumptions about the very nature of language. This article aims to fill this gap in the literature by offering a detailed overview of 10 key features which, from a Bourdieusian point of view, can be regarded as inherent in language. On the basis of this enquiry,the study seeks todemonstrate that——contraryto commonbelief——there is not only a Bourdieusian sociology of language but also a Bourdieusian philosophy of language, which provides a useful theoretical framework for examining the unavoidable conditions of the real speech situation. The paper draws to a close by reflecting on the flaws and limitations of Bourdieu’s approach to language

Control laws of a synchronous machine fed by a PWM voltage source inverter

International audienceThe introduction of a micro-processor into a command loop permits us to envisage new control structures. In line with this, we propose to set up modern adjusters to control the electro-magnetic torque in the synchronous machine fed by a PMW inverter. The first technique, called STATE SPACE FEEDBACK, consists in decomposing the dynamics of the procedure into two time scales, and in giving a reduced-order action model. This reduced-state model serves as a base for the construction of a dynamic flux observer. We next develop a state space feedback allowing control of the transitory evolution of state variables in a speed variator. The second technique, called ADAPTIVE CONTROL, is concerned with setting-up a self-tuning regulator ensuring adaptation of the regulator's parameters as the function point. This technique requires a line identification procedure which permits knowledge of the different conefficients of the equivalent-transfer function

Torque control of a synchronous motor with field using a state feedback

International audienceIt is noted that the introduction of microprocessors in a control loop allows the implementation of new control structures. On the basis of this idea, the authors propose modern regulation techniques for the control of the electromagnetic torque of a synchronous motor. From the state-space representation of systems, they propose the decomposition of the process dynamic into two time scales, in order to give a reduced-order action model of the device. This reduced state model will be the basis for the construction of a flux observer, with a structure simple enough to be implemented, in real time, in the control loop of the motor. A modal control system which allows the control of the transient-state evolution of state variables in the speed drive is developed

A self-adaptive control of a variable speed drive using a synchronous machine associated with a PWM inverter

International audienceThe speed control of a self controlled Pulse Width Modulated converter fed synchronous motor drive, is usually done by an Integral-Proportional regulator. A digital simulation process shows that this of control guarantees, only for a particular speed range, a good dynamic behaviour. To overcome this disadvantage, the authors propose the implementation of a system which permits a real time adaptation of the regular parameters to the operational point. For this purpose, the identification of the transfer function is introduced. After a dynamic analysis of the system, this transfer function is choosen in such a way that the dynamic behaviour of the system is preserved. The resulted second order transfer function describes in a satisfactory way the behaviour of the system. The recursive least squares algorithm permits to calculate the different coefficients of the transfer function. This function which represents the system is not stationary, a "forgot factor" is added to the algorithm which privileged the new measurements with respect to the old one. in the second part of this paper, this identification is used to define an optimal regulator. Some simulations results show an adaptive character of the regulator with respect to operational points are presented

Transient-state Torque Control in autopiloted synchronous motors

International audienceThe introduction of microprocessors in a control loop allows the implementation of new control structures. Based on this idea, we propose modern regulation techniques for the control of the electromagnetic torque of a synchronous motor. From the state-space representation of systems, we propose the decomposition of the process dynamic into two time scales, in order to give a reduced-order action model of the device. This reduced state-model will be the basis for the construction of a flux observer, with a structure being simple enough to be implemented, in real time, in the control loop of the motor. At last, we develop a modal control system, which allows the control of the transient-state evolution of state variables in the speed drive

Transient-state Torque Control in autopiloted synchronous motors

International audienceThe introduction of microprocessors in a control loop allows the implementation of new control structures. Based on this idea, we propose modern regulation techniques for the control of the electromagnetic torque of a synchronous motor. From the state-space representation of systems, we propose the decomposition of the process dynamic into two time scales, in order to give a reduced-order action model of the device. This reduced state-model will be the basis for the construction of a flux observer, with a structure being simple enough to be implemented, in real time, in the control loop of the motor. At last, we develop a modal control system, which allows the control of the transient-state evolution of state variables in the speed drive

Control laws of a synchronous machine fed by a PWM voltage source inverter

International audienceThe introduction of a micro-processor into a command loop permits us to envisage new control structures. In line with this, we propose to set up modern adjusters to control the electro-magnetic torque in the synchronous machine fed by a PMW inverter. The first technique, called STATE SPACE FEEDBACK, consists in decomposing the dynamics of the procedure into two time scales, and in giving a reduced-order action model. This reduced-state model serves as a base for the construction of a dynamic flux observer. We next develop a state space feedback allowing control of the transitory evolution of state variables in a speed variator. The second technique, called ADAPTIVE CONTROL, is concerned with setting-up a self-tuning regulator ensuring adaptation of the regulator's parameters as the function point. This technique requires a line identification procedure which permits knowledge of the different conefficients of the equivalent-transfer function