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International audience; District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

The paper presents a study of a reduced order observer with the vector control of a series-connected two-motor drive supplied by a single inverter. The multimachine system consists of a six-phase induction machine and a three-phase induction machine. The stators windings of both machines are connected in series in appropriate manner. The dynamic decoupling of each machine from the group is obtained using the indirect vector control algorithm. Modeling of the multi-machine system showed the possibility of independent control of each machine in the group. The independent control is demonstrated by analyzing the characteristics of the torque and speed of each machine obtained via simulation of multi-machine system under indirect vector control scheme. A reduced-order observer is applied to sensor-less control of multimachine. The simulation results show that the closed-loop system performances are satisfactory using the proposed algorithm.

The two five-phase Induction Motor (IM) drive system that is serially connected is available in literature. The power supply of such system is considered as a matrix converter (a direct AC to AC converter system) by three and five-phases outputs. The main benefit from the drive topology is the sinusoidal source as a side current with a controllable input side power factor. The decoupled control is achieved similarly to the inverter based drive system. In this paper; the decoupled control of two five-phase induction machines serially connected and powered by a five-phase matrix converter as well as analytical and simulation results are presented.

This paper presents a new variable speed wind energy conversion systems (WECS). It is based on a six-phase asymmetrical squirrel cage induction generator (SCIG) and a matrix converter (MC) as power electronic interface between six-phase SCIG and electrical network. The analysis employs a rotor flux vector control algorithm and a scalar strategy modulated MC to control the generator. Characteristics of MC are used for maximizing the power tracking control when different wind speeds and delivering powers to the grid are simultaneously considered. The MC provides sinusoidal input and output voltages and a unity power factor, but causes an asymmetry in the generator. A current control strategy including the method of suppressing imbalance caused by this asymmetry is discussed. Some numerical simulations are carried out showing the effectiveness of the proposed WECS topology.

Direct torque control (DTC) based on artificial neural network (ANN) of a five-phase permanent magnet synchronous motor drive (PMSM) is presented in this paper. Using the mathematical model of the five-phase motor, DTC control strategy is developed, and the corresponding controllers are properly designed in order to provide independent torque and flux control. In order to improve the performance of the DTC, a neural network based DTC scheme is adopted instead of the DTC based on the look-up table. The employed neural network uses the Levenberg-Marquardt back propagation algorithm for the adjustment of weights to increase the learning process accuracy. The efficacy of the proposed method is verified by simulation for various dynamic operating conditions, and the system's performance is compared with conventional DTC. Scopus

This paper presents sliding mode control of sensor-less parallel-connected two five-phase permanent magnet synchronous machines (PMSMs) fed by a single five-leg inverter. For both machines, the rotor speeds and rotor positions as well as load torques are estimated by using Extended Kalman Filter (EKF) scheme. Fully decoupled control of both machines is possible via an appropriate phase transposition while connecting the stator windings parallel and employing proposed speed sensor-less method. In the resulting parallel-connected two-machine drive, the independent control of each machine in the group is achieved by controlling the stator currents and speed of each machine under vector control consideration. The effectiveness of the proposed Extended Kalman Filter in conjunction with the sliding mode control is confirmed through application of different load torques for wide speed range operation. Comparison between sliding mode control and PI control of the proposed two-motor drive is provided. The speed response shows a short rise time, an overshoot during reverse operation and settling times is 0.075 s when PI control is used. The speed response obtained by SMC is without overshoot and follows its reference and settling time is 0.028 s. Simulation results confirm that, in transient periods, sliding mode controller remarkably outperforms its counterpart PI controller. 2018 by the authors. Scopus

In this paper, we study the three-phase shunt active filter which is used for the compensation of the unbalance current. It's a novel active power filter (APF) for 3-phase 4-wire power system under an unbalanced linear load, this filter contains a three-level inverter voltage (cascading two two-level inverters) controlled by 3D- SVM strategy, this methode makes possible to control the fourth arm and the neutral current can be reduced. The aim of this study is to bring an unpolluted source into the power grid, where the simulation results are obtained by using MATLAB Environment.

This contribution presents the control of the variable speed wind energy conversion systems. It is based on a six-phase symmetrical induction generator combined to a matrix converter. Rotor flux vector control algorithm and a scalar strategy modulated matrix converter are used to control the wind energy conversion system. Characteristics of the matrix converter are used for maximizing the power tracking control when different wind speeds and delivering powers to the grid are simultaneously considered. Some numerical simulations are carried out showing the effectiveness of the proposed system.

The control of Doubly-Fed induction generator (DFIG), used in wind energy conversion, has been given a great deal of interest. Frequently, this control has been dealt with ignoring the magnetic saturation effect in the DFIG model. The aim of the present work is twofold: firstly, the magnetic saturation effect is accounted in the control design model; secondly, a new second order sliding mode control scheme using adjustable-gains (AG-SOSMC) is proposed to control the DFIG via its rotor side converter. This scheme allows the independent control of the generated active and reactive power. Conventionally, the second order sliding mode control (SOSMC) applied to the DFIG, utilize the super-twisting algorithm with fixed gains. In the proposed AG-SOSMC, a simple means by which the controller can adjust its behavior is used. For that, a linear function is used to represent the variation in gain as a function of the absolute value of the discrepancy between the reference rotor current and its measured value. The t...

Power may be segmented either at the converter, using a multilevel inverter, either at the machine, by performing a polyphase winding. Moreover, increasing numbers of phases enables improved power quality and reducing torque ripples with the advantage of fault tolerance related to the loss of one or more phases. This class of system offers a reduction of design time, costs and the optimization of the volume of embedded systems. The objective of this work is to order, model and characterize the behavior of a training system multimachines composed of two five phase synchronous permanent magnet motors connected in series using two static converters.

In this paper, the vector control of a parallel-connected two five-phase permanent magnet synchronous machines (PMSMs) drive supplied by a single current-controlled voltage source inverter is presented. This system consists of a two five-phase PMSMs; the stators windings of both machines are connected in parallel in appropriate manner by using of the phase transposition property, which allows a decoupled control of the two machines. Based on the mathematical model of the multi-machine drive system, the decoupled dynamic of each machine from the group is obtained using the vector control algorithm. The independent control is ensured by controlling the stator currents and the speed of each machine under vector control consideration. Selected simulation results are presented to validate the effectiveness of the proposed control method under various dynamic operating conditions.

This paper presents the powers control of a variable speed wind turbine (WT) device based on a doubly fed induction generator (DFIG). Indeed, to increase the efficiency of the WT system, a robust variable structure control has been applied. DFIG has been previously presented in several works with diverse control diagrams using generally conventional PI controllers. Nevertheless, this type of controllers does not sufficiently handle some of WT resource characteristics such as wind fluctuations effects. Indeed, these can reduce WT performances. Furthermore, DFIG parameter variations should be accounted for. In this context, this paper proposes a high-order sliding mode to control the WT DFIG. Simulation results show that the proposed approach presents attractive features such as chattering-free behavior, good response to speed variations and robustness against machine parameter variations compared to the conventional first order sliding mode technique and even fuzzy sliding mode one.

In this paper, Sliding Mode controller has been sized to control multi-cell converters configured as a three-phase multicellular inverter. Unlike traditional inverters, multicellular inverters have the following advantages: lower switching frequency, high number of output levels, and less voltage constraints on the power switch. Significant performances are provided with this structure, which is constituted with flying capacitors. The main purpose of this paper is to present the model and generate commutation sliding-surfaces based on a Lyapunov function. The performed simulations point the efficiency of the proposed strategy with a three-phase multicellular inverters and allow to assess the performances and the robustness of the synthesized controller.

In this paper, a direct toque control (DTC) and space vector modulation (SVM) are combined to control a five-phase permanent magnet synchronous motor drive (PMSM). Based on the mathematical model of five-phase motor, DTC control strategy is developed, and the corresponding controllers are properly designed in order to provide independent torque control. Five-phase SVM is adopted, instead of look-up table, to improve the overall performance of multiphase drive. The efficacy of the proposed method is verified by simulation at various dynamic operating conditions.

In this paper, a control strategy of scalar modulation with three intervals and vector control technique for matrix converter fed induction motor drive system is proposed. By applying this control strategy, we are able to combine the advantages of matrix converter and the advantages of the vector control. Simulation results are shown to demonstrate the effectiveness of the proposed control scheme

In this paper, a control strategy of scalar modulation with three intervals and vector control technique for matrix converter fed induction motor drive system is proposed. By applying this control strategy, we will be able to combine the advantages of matrix converter and the advantages of the vector control. Simulation results are shown to demonstrate the effectiveness of the proposed control scheme.

In this paper, a control strategy of scalar modulation with three intervals and vector control technique for matrix converter fed induction motor drive system is proposed. By applying this control strategy, we are able to combine the advantages of matrix converter and the advantages of the vector control. Simulation results are shown to demonstrate the effectiveness of the proposed control scheme.