Abdolreza Esmaeli | Shahid Beheshti University (original) (raw)

Papers by Abdolreza Esmaeli

ABSTRACT Mitigation of the adverse effects of PWM inverter through active filter technique is dis... more ABSTRACT Mitigation of the adverse effects of PWM inverter through active filter technique is discussed in this paper. A PWM inverter fed ac motor drive system capable of suppressing all the adverse effects of PWM inverter based on active cancellation method is developed. An active EMI filter proposed for this system is characterized by sophisticated connection of two small separate filters, which they can mitigate common mode voltages produced by PWM inverter and can suppress leakage current. As a result small active filter with ability of reducing of all the adverse effects is approached. Whole system is modeled and simulated based on SABER simulator. Simulations are verified by experimental results, which show the reduction characteristics of the shaft voltage, bearing current, common mode current, and leakage current

哈尔滨工业大学学报(英文版), 2007

Modeling and simulation of induction motor drive system to investigate and mitigate the adverse e... more Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system including mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results show the excellent performances of proposed solution including active and passive filters.

Iet Electric Power Applications, Mar 25, 2021

This article presents a novel Direct Field-Oriented Control (DFOC) strategy for Fault-Tolerant Co... more This article presents a novel Direct Field-Oriented Control (DFOC) strategy for Fault-Tolerant Control (FTC) of wye-connected 3-Phase Induction Machine (3-PIM) drives under the stator winding open-phase failure. In the proposed control strategy, instead of flux measurement, an Extended Kalman Filter (EKF) for flux estimation is used. The introduced controller with minor modifications can be used during normal and stator winding open-phase failure conditions. With the proposed DFOC system, the speed and torque pulsations that normally happen during the open-phase failure can be reduced. The performances of the proposed EKF-based DFOC strategy and the conventional control strategy for a faulted machine using simulations and experiments under different operation conditions are compared. Simulation and experimental results demonstrated an important improvement in speed and torque pulsations through this type of fault. Results also confirmed the superiority of the proposed EKF-based DFOC scheme over the conventional control scheme to balance the faulted machine phase currents. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Global Journal of Research In Engineering, Jan 29, 2018

In this paper the digital pulsed power system to supply a very small repetitive Mathertype Plasma... more In this paper the digital pulsed power system to supply a very small repetitive Mathertype Plasma Focus Device (20 J) is presented. The structure of this electrical system included a pulsed power supply and a Microcontroller based control system. In Plasma Focus Devices a dc power supply charges a high voltage capacitor and then this saved energy discharges between two coaxial electrodes using a controllable spark gap switch. The procedure of control the capacitor charging and discharging are explained in this paper. Finally, the experimental results of electrical discharge and pinch shaping in plasma focus in different working conditions are presented and a good repetitive performance in a wide domain of working conditions is seen.

Iete Journal of Research, Feb 16, 2021

The improved three-dimensional imaging system by near-infrared light emission in breast tissue to... more The improved three-dimensional imaging system by near-infrared light emission in breast tissue to more accurate diagnosis of tumour is presented in this paper. Based on the repeated experiments in ...

ABSTRACT Modeling and suppression of PWM inverter's adverse effects are studied in this p... more ABSTRACT Modeling and suppression of PWM inverter's adverse effects are studied in this paper. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system included mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results shown the excellent performances of proposed solution including active and passive filters

PWM inverters are widely used in industrial, commercial and residential application such as motor... more PWM inverters are widely used in industrial, commercial and residential application such as motor drives. In three-leg inverters for three-phase applications the occurrence of common mode voltage is inherent due to asymmetrical output pulses. It has been found that the high dv/dt and high switching frequency together with the common mode voltages generated by PWM inverters have caused many adverse effects such as shaft voltage, bearing current, leakage current, motor terminal over voltage and electromagnetic interference (EMI). The EMI generated by such systems is increasingly causing concerns, as the electromagnetic compatibility (EMC) regulations become more stringent. In order to comply with these international EMC regulations, an EMI filter is often necessary. The major objective of this book is to investigate and suppress of the adverse effects of PWM inverters. Theoretical analysis of all the adverse effects is presented in this book. Several passive and active EMI filters and...

Z. Farajzadeh, A. Esmaeli(Ph.D.) ∗∗ Abstract Iran accounts for more than 50 percent of pistachio ... more Z. Farajzadeh, A. Esmaeli(Ph.D.) ∗∗ Abstract Iran accounts for more than 50 percent of pistachio world market, having a leading role in price formation process of pistachio in international market. The objective of this study is to investigate the price transmission pattern between domestic and world markets of pistachio. Regarding the applied dataset analyses were performed in two parts of time series (1972-2005) and panel data (1989-2005). Examination of causality between domestic and world prices showed a long run reciprocal relation between them. Analyses based on the times series data showed a long run symmetric price transmission in both of domestic and world markets. However, price transmission pattern was found asymmetric in short run, showing a more rapid and perfect transmission of price decrease as compared to price increase. Based on the results, increase in Iran’s share in world market may lead to increase in magnitude of price transmission to domestic market. The panel...

Article history: Received 25 March 2014 Received in revised form 20 April 2014 Accepted 15 May 20... more Article history: Received 25 March 2014 Received in revised form 20 April 2014 Accepted 15 May 2014 Available online 5 June 2014

IETE Journal of Research, 2021

International Transactions on Electrical Energy Systems, 2020

Background: 3ϕ Induction Machine (IM) drives are broadly used in different industrial application... more Background: 3ϕ Induction Machine (IM) drives are broadly used in different industrial applications. During failure conditions, 3ϕ IM drive systems cannot continue its optimal performance. Aims: The present study presents a method for indirect rotor field-orientated control (IRFOC) of star-connected 3ϕ IM drives during open-phase failure (OPF) condition. In addition, in this study the particle swarm optimization algorithm was used to determine the coefficients of proportional-integral (PI) controllers in the OPF mode. Materials & Methods: In the proposed method, two unbalanced currents and voltage rotational matrices are utilized to change the asymmetrical structure of the faulty 3ϕ IM equations to the equations with a symmetrical structure. Using these matrices, the speed control of the faulty 3ϕ IM can be realized with minor changes in the conventional IRFOC structure including control parameters, transformation matrices, and coefficients of PI controllers. Results: Experimental results were presented during various operating conditions on a 1 HP star-connected 3ϕ IM drive system. Discussion: The experimental tests in different operating conditions showed good performances of the proposed control system during both the steady-state and the transient periods. Conclusion: The proposed control method exhibited a significant improvement in reducing the speed, torque, and flux oscillations, compared to the

2006 1st International Symposium on Systems and Control in Aerospace and Astronautics

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2016

Abstract In this research work, the current density of polymer–carbon nanotube nanocomposite in d... more Abstract In this research work, the current density of polymer–carbon nanotube nanocomposite in different weight percentages of nanotubes, over the radiation absorbed dose under a fixed DC voltage for different polymer matrices such as high density polyethylene, polycarbonate, polyethylene terephthalate, polymethyl methacrylate, and polystyrene was investigated via finite element method. The predicted electrical percolation threshold values in different composites were validated by experimental results published by other scientists. The absorbed dose value was considered as multiplying of heat capacity and temperature rise of the composite, regarding the calorimetric approach. Results show that the polymer type having different characteristics of relative permittivity and heat capacity could affect the sensitivity and working dose range of the composite as a dosimeter.

Consider a wire-array liner which made of wires. Electric current that passes through the wire, a... more Consider a wire-array liner which made of wires. Electric current that passes through the wire, a magnetic field is created around it that can be calculated. An electromagnetic force (J B ) is applied to each wire. In this way, we can compute the external magnetic field around the liner, with assumption: the field was created by wires with infinite length that is not the reality. So, this calculation only gives some order of magnitude. Some evidence of a helical m=1 unstable kink mode at late times in the discharge, but it does not appear at stagnation. The time of stagnation, mainly long wavelength m=0 modes can be. Calculations and estimation at the confining time is difficult because of the pressure and field gradient [1,2]. But, these gradients are not at stagnation and equations become easier. So, all calculations were performed for stagnation moment. Figure 1 shows the configuration of Z-Pinch at the stagnation. So for Magnetic field can be written [3]:

This paper presents a new salient pole synchronous generator. Due to saturation of conventional s... more This paper presents a new salient pole synchronous generator. Due to saturation of conventional synchronous generators (SGs), permanent-magnet-assisted salient-pole synchronous generators (PMa-SGs) are presented. PMa-SGs are a new type of salientpole synchronous machines that has permanent magnets (PMs) between the adjacent pole shoes. Placing PMs between adjacent pole shoes leads to a reduction in flux saturation plus an increase in armature flux linkage. In other words, machine can operate at higher capacity. In this paper, a comparative study is carried out between conventional SGs and PMa-SGs based on finite element analysis (FEA). This is done via simulation of a PMa-SG compared to a traditional SG. Simulation Results show superiority of PMa-SGs over SGs.

International Transactions on Electrical Energy Systems, 2021