Mona N. Eskander

Electronics Research Institute · Power Electronics and Energy Conversion

In this paper, the starting performance of a double-fed induction generator (DFIG) operating at super-synchronous speed is investigated when varying the values of the DC link capacitor. The starting transients, the settling time, and the harmonics of the stator and rotor currents and voltages are investigated as a function of the DC link capacitor...

In this paper, the effect of unsymmetrical grid voltage sag on the performance of a slip power recovery drive is studied, and two strategies to mitigate its effects are investigated. The first strategy consists of three phase parallel RL impedance connected to the rotor circuit. The second strategy consists of three phase LCL filter connected to th...

In this paper, the effect of unsymmetrical grid voltage sag on the performance of a slip power recovery drive is studied, and two strategies to mitigate its effects are investigated. The first strategy consists of three phase parallel RL impedance connected to the rotor circuit. The second strategy consists of three phase LCL filter connected to th...

This paper presents three proposed schemes to mitigate the effect of unsymmetrical voltage-to-ground fault on a wind-driven grid-connected Double Fed Induction Generator (DFIG). The first tested scheme comprises a static compensator (STATCOM) connected to the DFIG stator, while a three-phase parallel RL external impedance is connected to the rotor...

This paper presents three-proposed schemes to mitigate the effect of unsymmetrical voltage sag fault on a wind-driven grid-connected Double Fed Induction Generator (DFIG). The first tested scheme comprises a static compensator (STATCOM) connected to the DFIG stator, while a three-phase parallel RL external impedance is connected to the rotor circui...

Starting voltage and current transients in slip energy recovery drives (SERD) may damage the stator and rotor windings. The resulting torque oscillations damage the induction machine mechanical parts. In this paper three schemes for damping starting transients and torque oscillations are proposed. In the first scheme a parallel RL impedance is conn...

This paper presents an integrated solution for a fault-tolerant three-phase permanent magnet synchronous motor (PMSM) field-oriented control drive subjected to an open-phase fault (OPF) integrated with effective fault-tolerant detection methodology. The fault detection methodology is based on model predictive current control (MPCC), which is easy t...

This paper presents an integrated solution for a fault-tolerant three-phase permanent magnet synchronous motor (PMSM) field-oriented control drive subjected to an open-phase fault (OPF) integrated with effective fault-tolerant detection methodology. The fault detection methodology is based on model predictive current control (MPCC), which is easy t...

This paper compares the performance of a wound rotor induction motor drive (WRIM) with two rotor impedance profiles. The first system involves a diode rectifier followed by variable impedance in the rotor circuit. The second system involves a three-phase variable impedance in the rotor circuit. The comparison concerns the magnitude of starting tran...

The paper validated a new Compensating device for Fault Ride Through (FRT) the permanent magnet synchronous motors (PMSM) driving AC Drives used in Electric Vehicle. The electric vehicle utilizes two PMSMs to drive the two front wheels. The battery source is regulated and controlled by a boost type dc-dc converter. The new FRT compensating device i...

In this paper a novel compensating circuit, composed of capacitors, one IGBT switch, and a diode bridge is designed and employed within a SOFC distributed generation system connected to a micro-grid. The DG system consists of the FC stack, a Cuk converter, a three phase inverter, the proposed compensating circuit, and Type 2 Fuzzy logic controller...

In this paper a novel .compensating circuit, composed of capacitors, one IGBT. switch, and a diode bridge is designed and employed .within a SOFC distributed generation system connected to .a micro-grid. The DG system consists of the FC stack, a. Cuk converter, a three phase inverter, the proposed .compensating circuit, and Type 2 Fuzzy logic contr...

The effect of three-phase grid fault on the performance of a wind- driven single machine-brushless double fed induction generator (SM-BDFIG) is investigated. The fault-ride-through (FRT) of the grid-connected SM-BDFIG is then studied when installing a Static Synchronous Compensator (STATCOM) between the grid and the generator. Recovery from the gri...

The effect of three-phase grid fault on the performance of a wind-driven single machine-brushless double fed induction generator (SM-BDFIG) is investigated. The fault-ride-through (FRT) of the grid-connected SMBDFIG is then studied when installing a Static Synchronous Compensator (STATCOM) between the grid and the generator. Recovery from the grid...

The effect of three-phase grid fault on the performance of a wind-driven single machine-brushless double fed induction generator (SM-BDFIG) is investigated. The fault-ride-through (FRT) of the grid-connected SM-BDFIG is then studied when installing a Static Synchronous Compensator (STATCOM) between the grid and the generator. Recovery from the grid...

In this paper two devices are proposed for fault ride through (FRT) of an adjustable speed drive (ASD) connected to a distribution system. The FRT ability of the system is tested first by connecting a dynamic voltage restorer (DVR) between the ac supply and the ASD, then by connecting an ultracapacitor with the DVR. Two types of faults are investig...

The effect of three-phase grid fault on the performance of a wind-driven single machine-brushless double fed induction generator (SM-BDFIG) is investigated. The fault-ride-through (FRT) of the grid-connected SM-BDFIG is then studied when installing a Static Synchronous Compensator (STATCOM) between the grid and the generator. Recovery from the grid...

Hybrid PV-wind generation systems have increased significantly due to the rapid improvement in power electronics techniques. In this paper, three switching techniques for mitigating the output harmonics of a PV-wind hybrid generation system are investigated. The proposed hybrid system consists of a PV panel connected to the grid via a DC/DC convert...

Abstract: In this paper a novel model for wind speed frequency distribution (WSFD) is proposed and tested using the Egyptian Atlas wind data for 29 areas. The accuracy of this model, named 3-M model, is proved to be the same as Weibull model accuracy but with less complexity and lower calculation time. The capacity factor and the cost/kWh generated...

In this paper an integrated system of WECS, battery storage and controller is proposed to supply electrical energy to a small community in a remote area in Egypt. The layout and the configuration are presented and discussed. Also, a new wind speed frequency distribution model is proposed based on the prevailing wind speed in this area. The validity...

In this paper an integrated system of WECS, battery storage and controller is proposed to supply electrical energy to a small community in a remote area in Egypt. The layout and the configuration are presented and discussed. Also, a new wind speed frequency distribution model is proposed based on the prevailing wind speed in this area. The validity...

Abstract: In this paper the sub-harmonics associated with a specially designed single machine brushless doubly fed induction generator (SM-BDFIG) are analyzed at super-synchronous speeds. The SM-BDFIG is coupled to a variable speed wind turbine, and its rotor circuit is connected to a 3-phase rectifier feeding Li-ion batteries. A mathematical model...

In this paper the dynamic performance of the specially-designed Single Machine Brushless Doubly-Fed Induction Generator "SM-BDFIG" coupled to variable speed wind turbine is investigated. The rotor voltage of the SM-BDFIG during super-synchronous operation is used to charge a number of batteries, connected to the rotor via a 3-phase bridge rectifier...

In this paper the dynamic performance of a stand-alone wind-driven Single Machine-Brushless Double Fed induction Generator (SM-BDFIG), supplying different loads in remote area is investigated. The battery embedded in the frame of the specially designed SM-BDFIG is used for energy storage in the super synchronous range of operation. The stored energ...

In this paper the sub-harmonics associated with a specially designed single machine brushless doubly fed induction generator (SM-BDFIG) are analyzed at supersynchronous speeds. The SM-BDFIG is coupled to a variable speed wind turbine, and its rotor circuit is connected to a 3- phase rectifier feeding Li-ion batteries. A mathematical model, using Fo...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

In this paper a simplified mathematical model of a single machine brushless double fed induction generator (SM-BDFIG) connected to a variable speed wind turbine is presented. The SM-BDFIG consists of a slip ring induction machine, which is the main generator, a converter, and a battery pack mounted on the same shaft. In the super-synchronous speed...

In this paper a simplified mathematical model of a single machine brushless double fed induction generator (SM-BDFIG) connected to a variable speed wind turbine is presented. The SM-BDFIG consists of a slip ring induction machine, which is the main generator, a converter, and a battery pack mounted on the same shaft. In the super-synchronous speed...

In this paper, the dynamic performance of the specially-designed Single Machine Brushless Doubly-Fed Induction Generator "SM-BDFIG" coupled to variable speed wind turbine is investigated. The rotor voltage of the SM-BDFIG during super-synchronous operation is used to charge a number of batteries, connected to the rotor via a 3- phase bridge rectifi...

In this paper, the dynamic performance of the specially-designed Single Machine Brushless Doubly-Fed Induction Generator "SM-BDFIG" coupled to variable speed wind turbine is investigated. The rotor voltage of the SM-BDFIG during super-synchronous operation is used to charge a number of batteries, connected to the rotor via a 3- phase bridge rectifi...

The Unified Power Quality Controller (UPQC) device is an integration of a series active filter and a shunt active filter. The main purpose of a UPQC is to compensate for voltage flicker, reactive power, and harmonics. It has the capability of improving power quality at the point of installation on power distribution systems or industrial power syst...

The Unified Power Quality Controller (UPQC) device is an integration of a series active filter and a shunt active filter. The main purpose of a UPQC is to compensate for voltage flicker, reactive power, and harmonics. It has the capability of improving power quality at the point of installation on power distribution systems or industrial power syst...

This paper compares the effectiveness of installing two types of FACTS devices, namely the Static Synchronous Compensator "STATCOM", and the Unified Power Quality Controller "UPQC" to enhance the low voltage ride through "LVRT" capability of a grid-connected wind energy conversion systems (WECS) employing a doubly fed induction generator (DFIG). Th...

This paper compares the effectiveness of installing two types of FACTS devices, namely the Static Synchronous Compensator "STATCOM", and the Unified Power Quality Controller "UPQC" to enhance the low voltage ride through "LVRT" capability of a grid-connected wind energy conversion systems (WECS) employing a doubly fed induction generator (DFIG). Th...

In this paper the dynamic performance of a stand- alone wind-driven Single Machine-Brushless Double Fed Generator (SM-BDFIG), supplying different loads in remote area is investigated. The battery embedded in the frame of the specially designed SM-BDFIG is used for energy storage in the super synchronous range of operation. The stored energy isused...

A stand-alone efficient robust photovoltaic (PV)-Electrolyzer Scheme using a PV-Array, a DC-DC buck-boost converter, an Electrolyzer, a hydrogen tank, and an additional Fuel Cell (FC) stack feeding an standalone autonomous load is investigated and validated for efficient energy utilization, voltage stabilization and maximum power point tracking (MP...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

Load excursions in PV powered DC interface Systems can cause loss of energy utilization and voltage transients as well as inrush current conditions, which leads to inefficient PV energy utilization and possible damage to sensitive loads. Large variation in load demand and /or Source PV-voltage leads to both inefficient operation and load voltage ex...

This paper discusses the effectiveness of installing two types of FACTS devices, namely STATCOM and DVR to enhance the fault ride through (FRT) capability of a doubly fed induction generator (DFIG) applied in wind energy conversion systems (WECS). The response of the DFIG to a 3-phase ground fault is investigated with each of these devices. Compari...

In this paper a new design for brushless doubly fed induction machine for operation as generator in wind energy systems is proposed. This machine, named single machinebrushless doubly fed induction generator (SM-BDFIG) is composed of three main components; a regular three phase wound rotor induction machine, a power electronic converter, and a pack...

Wind-Diesel hybrid power systems are particularly suited for locations where wind resource availability is high and the cost of diesel fuel and generator are reasonable. In this paper, a control technique is designed to adjust the hybrid system performance aiming at minimum fuel consumption and continuous supply of critical loads. The research inve...

The issue of renewable energy is becoming significant due to increasing power demand, instability of the rising oil prices and environmental problems. Among the various renewable energy sources, fuel cell is gaining more popularity due to their higher efficiency, cleanliness and cost-effective supply of power demanded by the consumers. This paper s...

Abstract In this paper the fluctuations of the output power of wind energy conversion systems (WECS) employing doubly fed induction generator (DFIG) due to different wind speed profiles is fully investigated. Power output fluctuations during starting are also, investigated. The wind speed variations are approximated by step functions. A mathematica...

In this paper the quality of power generated from wind energy conversion system employing a double fed induction generator (DFIG) is investigated. The DFIG performance is tested with 3 types of converters interfacing the rotor with the grid. These are: the six-step thyristor inverter with diode rectifier, six-step IGBT inverter with diode rectifier...

In this paper the dynamic behavior of a double-output induction generator (DOIG) driven by wind turbine under wind speed variation and during and after grid faults, is investigated. Two damping methods are tested to reduce the high transient values of currents and voltages at different parts of the wind energy conversion system. First, connecting 3...

In this paper the dynamic behavior of a double-output induction generator (DOIG) driven by wind turbine under wind speed variation and during and after grid faults, is investigated. Two damping methods are tested to reduce the high transient values of currents and voltages at different parts of the wind energy conversion system. First, connecting 3...

The issue of renewable energy is becoming significant due to increasing power demand, instability of the rising oil prices and environmental problems. Among the various renewable energy sources, fuel cell is gaining more popularity due to their higher efficiency, cleanliness and cost-effective supply of power demanded by the consumers. This paper s...

In this paper the quality of power generated from a wind energy conversion system employing a double fed induction generator (DFIG) is investigated. The DFIG performance is tested with 3 types of converters interfacing the rotor with the grid. These are: universal converter, 2-level bridge converter, and 3-level bridge converter. A comparison betwe...

series and shunt active power filters for enhancement of power system stability. The proposed UPQC consists of two independent active filters, each with its own dc link, a device known as "OPEN UPQC". The OUPQC is connected to a low voltage grid supplying industrial loads, mainly AC drives. Two controllers are proposed for operating the UPFC, namel...

In this paper, the operation of the Double Fed Induction Generator (DFIG) in the range from synchronous speed down to sub-synchronous speeds is analyzed using the power-flow approach. The objective of this analysis is to determine a ceiling for the rating of the converter interfacing the rotor of the wind driven double fed induction generator (DFIG...

The paper deals with a Unified Power Quality Conditioner (UPQC), which aims at the integration of series and shunt active power filters for enhancement of power system stability. The proposed UPQC consists of two independent active filters, each with its own dc link, a device known as "OPEN UPQC". Power system stability investigated includes fast r...

In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Fo...

In this paper two modes of operating a wound rotor induction machine as a generator at sub-and super-synchronous speeds in wind energy conversion systems are investigated. In the first mode, known as double fed induction generator (DFIG), the rotor circuit is fed from the ac mains via a controlled rectifier and a forced commutated inverter. Adjusti...

This paper investigates two methods for mitigation of voltage dips and voltage swells in a grid to which a wind energy conversion system (WECS) is connected. The two mitigation methods are the dynamic voltage regulator (DVR), and the static compensator (STATCOM). The wind energy system employs permanent magnet synchronous generator (PMSG). It is we...

In this paper, an accurate method for sensorless control of permanent magnet brushless motors is explained. The method doesn't include any modification to the classical construction of such motors and can be easily integrated within the drive electronics. It is applicable to both motor types, i.e. those with sinusoidal or trapezoidal back EMF.. The...

In this paper, two small isolated hybrid power systems that used a parallel combination of a nature-dependent wind turbine, and fuel cells are investigated. This study examines the technical feasibility of the two autonomous renewable energy systems at a location where natural gas is available. The first system consists mainly of wind turbines, ele...

In this two-part paper, a powerful and accurate method for sensorless control of permanent magnet brushless motors is explained. The method doesn't include any modification to the classical construction of such motors and can be easily integrated within the drive electronics. It is applicable to both motor types, i.e. those with sinusoidal or trape...

This paper presents a method to maximize the power generated from a 3-turbine wind farm, and supply it to the grid with high power quality. Different control methods are applied to each subsystem; generation, aggregation, and finally grid connection. The control goal in the generation subsystem is to extract maximum wind power below rated wind spee...

In this paper, a powerful method for sensorless control of permanent magnet brushless motors (PMBM) is explained. The method doesn't include any modification to the classical construction of such motors and can be easily integrated within the drive electronics. It is applicable to both motor types, i.e. those with sinusoidal or trapezoidal back EMF...

In this two-part paper, a powerful and accurate method for sensorless control of permanent magnet brushless motors is explained. The method doesn't include any modification to the classical construction of such motors and can be easily integrated within the drive electronics. It is applicable to both motor types, i.e. those with sinusoidal or trape...

In this paper an on-line neural network-based scheme is proposed for high efficiency operation of an Interior Permanent Magnet Synchronous Motor (lPMSM). The dynamics of the motorlload are modeled on-line and controlled using two neural network (NN)-based schemes. The first controller (NNT) is designed to control the motor torque. The output of NNT...

In this paper, a hybrid Photovoltaic (PV)-fuel cell generation system employing an electrolyzer for hydrogen generation is designed and simulated. The system is applicable for remote areas or isolated loads. Fuzzy regression model (FRM) is applied for maximum power point tracking to extract maximum available solar power from PV arrays under variabl...

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system (WECS) employing a permanent magnet synchronous generator, is proposed. The permanent magnet generator (PMG) supplies a DC load via a bridge rectifier and two buck–boost converters. Adjusting the s...

In this paper an energy system comprising three energy sources, namely; PV, wind, and fuel cells, is proposed. Each of the three energy sources is controlled so as to deliver energy at optimum efficiency. Fuzzy logic control is employed to achieve maximum power tracking for both PV and wind energies, and to deliver this maximum power to a fixed DC...

In this paper an energy system comprising three energy sources, namely; PV, wind, and fuel cells, is proposed. Each of the three energy sources is controlled so as to deliver energy at optimum efficiency. Fuzzy logic control is employed to achieve maximum power tracking for both PV and wind energies, and to deliver this maximum power to a fixed DC...

In this paper, maximum efficiency operation of two types of permanent magnet synchronous motor drives, namely; surface type permanent magnet synchronous machine (SPMSM) and interior type permanent magnet synchronous motor(IPMSM), are investigated. The efficiency of both drives is maximized by minimizing copper and iron losses. Loss minimization is...

The complete hardware and software design of a new microcomputer-based controller for a slip energy recovery induction motor drive is presented. The drive incorporates a three-phase rectifier, a smoothing reactor, three single-phase line commutated inverter, and three isolating transformers. The proposed controller allows operating the inverter in...

In this paper a utility interactive wind energy conversion system (WECS) with an asynchronous (AC–DC–AC) link is described. The control system has the objective of identifying and extracting the maximum power from the wind energy system and transferring this power to utility. A fuzzy logic control (FLC) technique has been implemented to design the...

In this paper the steady state characteristics of slip energy recovery drives (SERD) employing a three phase bridge recovery inverter (topology “A”), are compared with the characteristics of SERD employing three, single phase bridge inverters operating in the flywheel mode (topology “B”). The comparison comprises the waveforms of voltages and curre...

In this paper, the use of neural networks for identification and control of quasi-resonant converters (QRC) is investigated. The model of the DC-DC switching converter is implemented by means of a neural network emulator to identify the converter dynamics. The emulator reproduces the converter dynamic behavior accurately. Also a three-layer neural...

Fuzzy logic (FL) is proposed for controlling the saturated slip power recovery drive (SSPRD). The controlled system response to step changes in the reference speed in load torque, and changes in rotor resistance are presented. A comparison between the responses of the PI controlled and the FL controlled SSPRD to such variations is developed. The sa...

An economic automatic system for spray painting of a general three dimensional surface is described. The spray gun is mounted on the wrist of a six degree of freedom (6 DOF) industrial robot. The system functions by the method of camera space manipulation, using two CCD cameras to scan the surface dimensions off-line, and store them in a supervisor...

The aim of this work is to estimate and control the rotor voltage of a double excited induction machine DEIM that is necessary to operate it as a generator in wind energy conversion systems (WECS), with speed range extending from the sub synchronous range to double the synchronous speeds. For efficient power generation, the DEIM is to be operated a...