This paper studies modelling and simulation for an inverter coupled transformer and the effects caused by source side harmonics on it. It also provides an insight to smart analysis and control of the same. These harmonics are present in most power electronic sources alike an inverter which is frequently used in renewable applications. The extended effect of source side harmonics on transformer primary can be shown on the transformer core hysteresis curve. The effect of harmonics is observed on the magnetization cycle with an electronic integrator circuit. The research uses a modified hysteresis model for the core with the effect of source harmonics taken in to consideration. The simplified hysteresis curve is plotted without removing the transformer from operation with measured data of voltages. Internet-of-things based smart control is proposed for remote operation and control of the transformer especially for use in remote microgrids and wind-farms. The proposed research is an operative tool for measurement and analysis of source harmonic effects on the core of the transformer. The outcome can be used for taking safety measures for extending the operating life of the transformer. The MATLAB/Simulink made simulations along with suitable experiments authenticate the proposed research.
In this paper, Speed Sensorless Vector Control of Double star Induction machine DSIM using sliding mode observer is presented. The search for the gains of conventional Luenberger observer in the sense of stability Lyapunov, oriented to sliding mode observer form, but the sign function caused the chattering effect, the replace it by function smooth are adopted. As a result, application of DSIM speed sensorless vector control using sliding mode has shown that is robust to load disturbances and / or reference speed change. The proposed control scheme is verified by simulation.
Effective congestion control is an issue strongly impacting basic features demanded from modern network environment as reliability, high and stable throughput, and low delays. These characteristics define the quality of communication channels. Optimizing network nodes configuration for only one of mentioned features, can exacerbate other parameters. This paper focuses on avoiding and alleviating network congestions using multi-objective optimization for gain setting of used controllers. Unlike in other presented approaches, in this case the non-stationary, discrete, dynamical model is discussed. The significant advantage of this approach is in the better reflection of the real environment conditions, where the transmission delay is floating. As the further development of the control strategy, the controller with the memory of previous steps have been deployed. Such control strategy mitigates the unfavorable impact of extended delays. Both proposed control strategies tune the presented model of communication channel to alleviate the results of sudden, unexpected network state changes. It is obtained by maximization of available bandwidth usage combined with minimization of buffer utilization. This supports avoiding undesirable congestion effects like packet dropping, retransmissions, high delay, and low network throughput.
The purpose of this study is to improve the control performance of a Doubly Fed Induction Generator (DFIG) in a Wind Energy Conversion System (WECS) by using both of the conventional Proportional-Integral (PI) controllers and an Artificial Neural Network (ANN) based controllers. The rotor-side converter (RSC) voltages are controlled using a stator flux oriented control (FOC) to achieve an independent control of the active and reactive powers, exchanged between the stator of the DFIG and the power grid. Afterward, the PI controllers of the FOC are replaced with two ANN based controllers. A Maximum Power Point Tracking (MPPT) control strategy is necessary in order to extract the maximum power from the of wind energy system. A simulation model was carried out in MATLAB environment under different scenarios. The obtained results demonstrate the efficiency of the proposed ANN control strategy.
This paper proposes a new speed and position sensorless control method of Interior permanent magnet synchronous motors (IPMSM) using sliding mode observer based on Active Flux concept. First, a new description of IPMSM dynamic model in the stationary reference frame using active flux concept is proposed. The model obtained suits for both SPMSM and IPMSM in the stationary reference frame, Therefore, all that sensorless controls proposed for SPMSM can be directly and easily applied to IPMSM. Secondly, from the measurement of the voltages and the currents, a new analysis of the observability property is developed. Then, the sliding mode observer (SMO) structure and its design method are described in the stationary reference frame by using the active flux equation. A “chattering” phenomenon is reduced by using this technique. The stability of the proposed SMO was verified using the Lyapunov function. The speed and position of the IPMSM are estimated based on back EMF which are related to the active flux. Moreover, the zero d-axis current control strategy is used to control the IPMSM. Finally, the proposed method on the proposed model has been simulated and tested to show the effectiveness of the proposed scheme.
The main objective of this work is the application of a new architecture of genetic algorithms to the induction machine design in order to improve their performance. The latter is proposed by our research team based on modified crossing and mutation operators who have fixed values for conventional genetic algorithms. In addition, this version is characterized by a double loop and a random crossover. Firstly, to demonstrate the ability to locate the global optimum with this version algorithm a mathematical function was used. Then we approached the second phase which its application in real time to the induction motor optimized design problem. Knowing that, the machine is a highly coupled with multivariable system and constraints. Finally, the results obtained have been analyzed where we have found that satisfactory and can be declared that adaptation algorithm is effective in locating rapidly the region in which the global optimum exists in relation to the classical genetic algorithm.
Line to Ground (LG) and Line to Line (LL) faults are the two most frequently encountered faults in any power system network. For the purpose of designing advanced protection systems, detection of the location as well as the identification of the type of fault, from a remote location is of paramount importance. In this paper a Discrete Wavelet Transform based statistical analysis has been carried out to detect the fault type and location of LG and LL faults. IEEE standard 9 bus system has been considered for this purpose. Faults are made to occur in the load buses and outgoing currents from the generator buses are analyzed by Discrete Wavelet Transform (DWT) as these current waveforms are non-stationary in nature. Statistical parameters are calculated from the approximate and detail coefficients which have been derived from the DWT. Based upon these parameters, a rule set has also been made. Simulation work is performed with the help of MATLAB. Methods proposed here can be helpful for designing better protection schemes.
The aim of this study is to evaluate the influence of the position of a DC/DC static converter between a source and a load with regard to the conducted EMC emissions measured on the source. An experimental model was established through the analysis of relevant stresses, such as the variation in the lengths of the source-converter, converter-load cables and the impact of the shield connection. Through this study, it was observed that the circuit was sensitive to too large variations in the capacities of common mode and of the link, and the results obtained make it possible to confirm the reality of the electromagnetic pollution of the static DC/DC converter "Buck" as a function of connections. The results of this research can be used in DC/DC network designs based on buck converters.
Network congestion is a phenomenon strongly impacting the real level of efficiency expected from the modern network environment. It has direct impact on reliability increase and high, stable throughput. It's also one of the main reasons of the end to end delay increase. These characteristics define the quality of communication channels. Optimizing network nodes configuration for only one of the given features can exacerbate the other parameters. This paper focuses on avoiding and alleviating network congestions using multiobjective optimization. This optimization process is used to adjust the controller gain and optimal reference signal. Unlike in other presented approaches, in this case, a dynamical, discrete, non-stationary model of communication channel is applied. It reflects delay conditions in a real environment, which are varying in time. The advantage of such approach rises from the comparison with analogue stationary models, what is also discussed in this research. Two different control strategies have been chosen to be subjected to the optimization process. The first one uses the constant, optimized reference value. The second one is using an adaptive reference value. The proposed strategy of congestion control is adjusting parameters of the presented models to alleviate undesirable results of sudden, network condition changes. It is obtained by maximization of available bandwidth usage combined with the minimization of buffer utilization. This approach supports avoiding harmful congestion effects like retransmission, packet dropping and high network delay, which eventually cause network throughput degradation.
Received: 1 June 2019 Accepted: 26 August 2019 In this paper, a well-known mathematical model of electric power transmission line under steady state conditions is considered. From this model, the mathematical expression that describes the resultant current along a power transmission line has been developed taking as starting point the end of the line. We use the fore-mentioned mathematical expression and the data of a typical electric transmission line to calculate how the current wave varies. The results are also graphed in order to have an optical view of how the current wave behaves. Finally, the results are analysed and the relative conclusions are drawn.
Received: 4 April 2019 Accepted: 17 September 2019 This paper proposes a novel dual three-phase Space Vector Modulation (SVM) for sixphase multilevel inverter to control a Six Phase Induction Machine (SPIM). The main idea is to control the six-phase multilevel inverter as two three-phase (1, 3 and 5 phases for the first one and 2, 4 and 6 phases for the second one) multilevel inverters separately by SVM of the N-level three-phase Separate DC Source (SDCS) inverter. This enables a great the simplification of the control algorithm for six phase multilevel (N level) inverter drive. In Six-Phase SVM, N6 vectors are used so if two level N=2, 3 level or 4 level, implies 64 vectors, 729 vectors, 15625 vectors are used respectively. However, in a proposed dual three-phase SVM, we use N3 vectors so if 2 level, 3 level or 4 level implies 8 vectors, 27 vectors, 125 vectors are used respectively to control the six-phase multilevel inverters as two three-phase multilevel inverter with the same three-phase multilevel SVM. Whereas the first three-phase inverter is composed by 1, 3, and 5 phases and the second three-phase is composed by 2, 4 and 6 phases. This allows to have a new modulation technique for six-phase multi-level inverter and a great simplification of the classical six-phase SVM control algorithm. The simulation results of the Indirect Field Oriented Control (IFOC) of six-phase induction machine drive fed by stacked multilevel inverters are given to highlight the performance of the proposed control structure.
The main objective of this paper is to apply fuzzy control to push-pull fly-back three-phase DC-DC convertor.For this purpose, firstly, the push-pull fly-back three-phase DC-DC convertor is investigated.This structure can operate in the entire range of D variations.The high impedance generated by coupler loopholes prevents trans-saturation.Finally, the simulation results show the accuracy of the converter's performance in two different values for the reference voltage.
Received: 2 April 2019 Accepted: 15 August 2019 Five-phase fault-tolerant induction motor (FPIM) with open-end winding (OEW) can offer low torque ripple and it has a merit of high fault-tolerant capability due to its large number of phases. In order to improve the operation performance under an open singlephase. This paper proposes a Remedial Backstepping Control (RBSC) technique for a FPIM-OEW with the ability to run the system before and after fault condition. Hence, the FPIM-OEW losses are decreased, which improves the overall machine efficiency. The proposed RBSC technique lies in the orthogonal reduced-order transformation matrix, which is derived from the fault-tolerant current references, and a new zero-sequence current related to torque ripple. Also, the effect of the open-phase fault on the motor model under the transformation matrix is discussed. The simulation results of the proposed technique under open single-phase are provided, wherein we demonstrate the effectiveness of the proposed strategy with a fast dynamic and steady-state performances as that under healthy operation.
In this paper, the experimental study has been carried out on CSTR in the presence of process faults which can possibly occur due to sudden and unexpected change in certain process parameters.The faults like change in flow rate and the change in agitator speed have been injected into the system individually.As a result, there is a change in the output of CSTR i.e. titration end point.For analysing the injected faults, the Euclidean distance classifier has been employed.Through the Euclidean distance classifier, the nature and magnitude of faults can be visualized.Moreover, while varying the speed of agitators, it has been observed that fault becomes prominent at high speed of each of the agitators.This correlates with the Euclidean distance results in which it is observed that in case the speed of agitators is high, the Euclidean distance is of a high value.This distance has been calculated for the various single faults, in which only a single parameter has been varied at a time.The findings of this research can be helpful for guiding the process operator regarding the severity of the faults.
Received: 15 June 2019 Accepted: 17 August 2019 The reliability of these cables was satisfactory, but their implementation had major drawbacks unwinding and pulling difficulties (due to the rigidity and the mass of cable), the long and delicate junction. At present, the replacement of insulated cables with paper impregnated with synthetic insulated cables has been evoked for reasons of the excellent qualities of synthetic insulators. Electrical stresses are essential parameters in the breakage of insulating materials such that the thickness of the insulator, or the minimum distance required between a conductor and ground that will depend on this maximum stress value. The importance of the study of the electric field in high voltage is essential because it constitutes: the most important constraint. The calculation of the electric field is governed by the Poisson's equation or Laplace. The resolution of these equations requires the knowledge of certain conditions on the boundaries of the studied domain. There are two main families of solving methods, one is analytical, gives exact values, and the other is approximate and is based on numerical methods.
There are various applications running over the Internet which generates a huge amount of traffic.So, Transport Layer takes the responsibility to manage this traffic and provides reliable, connection-oriented, end-to-end packet delivery service.Transmission Control Protocol (TCP) is a Transport Layer protocol, which provides these services.Each TCP variant provides a solution for specific problems.Utilization of the available bandwidth of the path with respect to the received ACK remains a challenge in long delay network.This paper presents a delay based congestion control approach which tries to maintain the data transmission according to the available capacity of the path.Simulation results show that proposed approach provides better results in terms of packet loss, throughput and interprotocol fairness as compare to other protocol.
