Shady M Sadek | Cairo University (original) (raw)
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Papers by Shady M Sadek
Applied Mechanics and Materials, 2011
To solve the problems of large flux linkage and torque ripple, difficulty to accurately control a... more To solve the problems of large flux linkage and torque ripple, difficulty to accurately control at very low speed in the conventional direct torque control (DTC) of permanent magnet synchronous motor (PMSM), the chattering free fast terminal sliding mode (FTSM) control is introduced into the PMSM DTC. The proposed control scheme not only preserves fast torque response merit, but also associates with the high robustness of terminal sliding mode. It can drive torque ripple to converge to the equilibrium point in finite time, reduce steady state error, has stronger robustness to motor parameter and disturbance,and it attenuates the chatter. This stability of system is proved by Lyapunov theorem in this paper. The simulation results are presented to the feasibility and effectiveness of this method.
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International Journal of Power Electronics and Drive Systems (IJPEDS)
Nowadays, direct torque control (DTC) of AC drives is one of the most interesting fast dynamic re... more Nowadays, direct torque control (DTC) of AC drives is one of the most interesting fast dynamic response motor control techniques. Permanent magnet synchronous motors (PMSM) are now replacing induction motors (IM) in a wide range of applications because of their salient merits such as high efficiency and compactness. Combining DTC and PMSM in one drive may result in excellent performance not only for torque dynamics but also for efficiency. DTC relies on the estimation of the stator flux and torque to be compared with the set points of the torque and flux. In the literature, there are various flux estimation methods and each one has its own merits and demerits. Comparisons of these various methods are discussed in this paper showing their effect on the drive performance through MATLAB/Simulink simulations.
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International Journal of Renewable Energy Research, 2020
Bookmarks Related papers MentionsView impact
IEEE Access, 2021
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Electric Power Systems Research
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This paper proposes a two-stage stochastic energy management (EM) in an isolated microgrid (MG) t... more This paper proposes a two-stage stochastic energy management (EM) in an isolated microgrid (MG) to decide for the day-ahead optimal dispatch. The dispatch aims to effectively manage the MG power sources, including intermittent renewable energy sources (RESs), battery energy storage systems (BESSs), and diesel generators such that the expected operation costs, reactive power costs, spinning reserve, and load shedding are minimized. The Generative Adversarial Networks (GANs) is utilized in this paper as a data driven scenario generation method to model the uncertainties in the output power of the RESs to be used in the stochastic programming formulation. Then, the fast forward scenario reduction algorithm is used to reduce the number of scenarios with the help of SCENRED/GAMS software. Usually, fuel consumption costs of diesel generators are considered to be dependent on active power generation only. However, neglecting the related reactive power costs might result in increased operation costs and deviations in the dispatches from the optimal solutions. Hence, this paper co-optimizes the costs related to both active and reactive powers of diesel generators. In addition, this study considers the reactive power capability of inverter-interfaced distributed energy resources (DERs). Moreover, the detailed models for the different resources are presented, especially for diesel generators where the actual capability curves are used instead of the widely used box constraints. The problem is formulated as a nonlinear programming problem in the General Algebraic Modeling System (GAMS) software and is solved by the CONOPT solver.
Bookmarks Related papers MentionsView impact
In this paper, a day-ahead energy management (EM) for isolated microgrids (MGs) is proposed to ob... more In this paper, a day-ahead energy management (EM) for isolated microgrids (MGs) is proposed to obtain the optimal dispatch such that the costs related to the fuel consumption of diesel generators, load shedding, and renewable energy curtailment are minimized. Usually, fuel consumption costs of diesel generators are considered to be dependent on active power generation only. However, neglecting the related reactive power costs might result in increased operation costs and deviations in the dispatches from the optimal solutions. Hence, this paper co-optimizes the costs related to both active and reactive powers of diesel generators. In addition, this study considers the reactive power capability of inverter-interfaced distributed energy resources (DERs). The energy management problem is formulated as a nonlinear programming problem in GAMS environment and is solved using the CONOPT solver. Four different cases are presented to show the effect of considering the reactive power costs of the diesel generators and the reactive power capability from the inverter-interfaced DERs on the operating costs and dispatch results of the isolated MG.
Bookmarks Related papers MentionsView impact
MEPCON Conference
Direct Torque Control (DTC) of AC drives is considered one of the most interesting high dynamic r... more Direct Torque Control (DTC) of AC drives is considered one of the most interesting high dynamic response motor control strategies nowadays. Permanent Magnet Synchronous Motors (PMSM) are now replacing Induction Motors (IM) in a variety of applications due to their valuable advantages like increased efficiency and compact size. The combination of DTC and PMSM in the same drive system leads to excellent performance not only for torque dynamics but also for efficiency point of view. DTC depends on the selection of the desired stator voltage vector from a look-up table called "switching selection table" to meet the torque and flux change requirements. In the literature, there are various switching tables according to the using of zero voltage vectors and the number of hysteresis comparator levels. Each table has its own merits and demerits in terms of torque response, speed response, torque and flux ripples and switching frequency (losses). Comparisons of these various switching tables are discussed in this paper showing their effect on the drive performance through MATLAB/Simulink simulations. Permanent Magnet Synchronous Motor (PMSM), Voltage Source Inverter (VSI), Switching Table, Matlab/Simulink.
Bookmarks Related papers MentionsView impact
Thesis Chapters by Shady M Sadek
Direct torque control (DTC) of AC drives is considered one of the most interesting high performa... more Direct torque control (DTC) of AC drives is considered one of the most interesting
high performance control techniques nowadays. Permanent magnet synchronous motors
(PMSM) are now replacing induction motors (IM) in a variety of applications due to
their valuable characteristics especially the increased efficiency and compact size. The
combination of DTC and PMSM in one drive system leads to high dynamic response
drive system that seems to be an interesting topic to gain the increased research in the
literature.
DTC offers high dynamic torque, flux, and speed responses better than that of Field
Oriented Control (FOC) technique with simple controller architecture that utilizes two
hysteresis controllers and a switching table to select the most suitable voltage vector to
meet the torque and flux requirements. No machine parameter dependences, no axes
transformation required, no voltage modulation techniques, and no current controllers
are the advantages of DTC over FOC. Comparisons between DTC and FOC of PMSM
are made through MATLAB simulations to show their characteristics with respect to
the other. It is found that DTC gives excellent dynamic responses in both torque and
flux but the ripple content is high.
DTC requires the estimation for both flux and torque. A lot of methods are found in
the literature to estimate the flux and the most powerful methods are compared via
simulations. Pure integration method of flux estimation is the basic method that has a
lot of demerits like offset, resistance variation dependence, initial value problem, and
low performance at low speeds. Low Pass Filter (LPF) is intended to solve the pure
integration problems but its performance at transient period is not good and there is
some drift in the flux beyond the actual flux. Modified integrator is also one of the
interesting flux estimation methods that gives better performance at both transient and
steady state conditions than that of LPF estimator but it contains PI controller and low
pass filters so that several tunings are required and complexity is increased. A flux
estimator uses tunable-cutoff-frequency-LPF is simple and accurate. It is used for IM
and never be used for PMSM. It is also compared and shows excellent results in both
transient and steady state periods which implies the effectiveness of it for PMSM as
well as IM.
Switching Look-up Table is a unique characteristic in a DTC drive and it has a lot of
schemes based on the number of hysteresis levels of the torque and flux comparators
and the inclusion / exclusion of the zero voltage vectors. Various switching tables
appeared in the literature are compared to judge the merits and demerits of each one
and to show their effect on the drive performance. A relatively new switching table
using modified definition of the flux sectors is used for PMSM for the first time and its
results are excellent because it avoids a fatal problem appeared in the table proposed by
Takahashi, the inventor of the DTC system.
Selection of the amplitude of the flux and torque hysteresis bands is a very
important issue in implementing the DTC drive system as they affect torque ripples,
flux distortion, switching losses, and current harmonics. Simulations are made to
show these effects. Trade off should be made to correctly choosing of the
hysteresis band amplitudes according to the performance requirements.
Torque / flux ripples and variable switching frequency are the main disadvantages of
DTC system. Solutions to these problems are an interesting researching aspect
nowadays. Increased number of voltage vectors and/or sectors, Space Vector
Modulation (SVM), Duty Ratio control, and Model Predictive Control (MPC)
techniques are the most common solutions to the problems of high ripple content and
variable switching frequency. The loss of the DTC simplicity is something that makes
these solutions inconvenient so that compromise studies should be done to select the
most suitable control technique that meets the application needs without increasing the
complexity of the system.
Digital Signal Processors (DSPs) are now considered the basic controllers used in
the motor control area. DSP programming is often done using hand written code by C
or Assembly languages which is very time consuming and very prone to errors.
Computer Aided Control System Design (CACSD) is some sort of block programming
can be implemented using Matlab/Simulink. The Simulink model itself can be
downloaded to the DSP which makes the real time control system design easier.
The complete description of the DTC-PMSM drive system is discussed showing the
power, control, measurement, and signal conditioning circuits used in the system. Six
step operation of the inverter as well as open loop V/F control of PMSM are
implemented in order to verify the effectiveness of the CACSD using Matlab/Simulink.
Bookmarks Related papers MentionsView impact
Drafts by Shady M Sadek
With the increasing interests on energy efficiency, energy cost, and environmental pro... more With the increasing interests on energy efficiency, energy cost, and environmental
protection, the development of electric vehicles (EVs) technology has been obvious
nowadays. Based on the air pollution regulations in the USA and Europe as well as a
lot of countries in the world, the fossil-fueled vehicles have been targeted as the major
source of emissions that create air po llution leading to the global warming crisis. The
oil resources in the earth are limited and the new discoveries of it are at a slower pace
than the increase in demand especially with the increase in the world population so
that the need for alternatives is becoming crucial.
The technologies involved in EVs are diversified and include electrical and
electronics engineering, mechanical engineering, automotive engineering, and
chemical engineering. EVs depend on which called electric propulsion, in which an
electric motor is used to drive the vehicle instead of the internal combustion engine
(ICE) and the energy sources are batteries, fuel cells, or capacitors instead of gasoline
or diesel fuel in the conventional ICE vehicles. Thus, power electronics technology
plays an important role in the electrical propulsion system in order to efficiently drive
the electric motor of the vehicle and control the power converters and the associated
electronic circuits.
An overview of the current status of power electronic drives for EVs and recent
research trends in EV motors, power converters, and energy storage systems will be
discussed. Challenges associated with designing, controlling, and operating the power
electronic converters used in EVs will be also discussed showing the latest
achievements in this field. Challenges and problems associated with power electronic
converters will be discussed also.
Bookmarks Related papers MentionsView impact
Applied Mechanics and Materials, 2011
To solve the problems of large flux linkage and torque ripple, difficulty to accurately control a... more To solve the problems of large flux linkage and torque ripple, difficulty to accurately control at very low speed in the conventional direct torque control (DTC) of permanent magnet synchronous motor (PMSM), the chattering free fast terminal sliding mode (FTSM) control is introduced into the PMSM DTC. The proposed control scheme not only preserves fast torque response merit, but also associates with the high robustness of terminal sliding mode. It can drive torque ripple to converge to the equilibrium point in finite time, reduce steady state error, has stronger robustness to motor parameter and disturbance,and it attenuates the chatter. This stability of system is proved by Lyapunov theorem in this paper. The simulation results are presented to the feasibility and effectiveness of this method.
Bookmarks Related papers MentionsView impact
International Journal of Power Electronics and Drive Systems (IJPEDS)
Nowadays, direct torque control (DTC) of AC drives is one of the most interesting fast dynamic re... more Nowadays, direct torque control (DTC) of AC drives is one of the most interesting fast dynamic response motor control techniques. Permanent magnet synchronous motors (PMSM) are now replacing induction motors (IM) in a wide range of applications because of their salient merits such as high efficiency and compactness. Combining DTC and PMSM in one drive may result in excellent performance not only for torque dynamics but also for efficiency. DTC relies on the estimation of the stator flux and torque to be compared with the set points of the torque and flux. In the literature, there are various flux estimation methods and each one has its own merits and demerits. Comparisons of these various methods are discussed in this paper showing their effect on the drive performance through MATLAB/Simulink simulations.
Bookmarks Related papers MentionsView impact
International Journal of Renewable Energy Research, 2020
Bookmarks Related papers MentionsView impact
IEEE Access, 2021
Bookmarks Related papers MentionsView impact
Electric Power Systems Research
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
This paper proposes a two-stage stochastic energy management (EM) in an isolated microgrid (MG) t... more This paper proposes a two-stage stochastic energy management (EM) in an isolated microgrid (MG) to decide for the day-ahead optimal dispatch. The dispatch aims to effectively manage the MG power sources, including intermittent renewable energy sources (RESs), battery energy storage systems (BESSs), and diesel generators such that the expected operation costs, reactive power costs, spinning reserve, and load shedding are minimized. The Generative Adversarial Networks (GANs) is utilized in this paper as a data driven scenario generation method to model the uncertainties in the output power of the RESs to be used in the stochastic programming formulation. Then, the fast forward scenario reduction algorithm is used to reduce the number of scenarios with the help of SCENRED/GAMS software. Usually, fuel consumption costs of diesel generators are considered to be dependent on active power generation only. However, neglecting the related reactive power costs might result in increased operation costs and deviations in the dispatches from the optimal solutions. Hence, this paper co-optimizes the costs related to both active and reactive powers of diesel generators. In addition, this study considers the reactive power capability of inverter-interfaced distributed energy resources (DERs). Moreover, the detailed models for the different resources are presented, especially for diesel generators where the actual capability curves are used instead of the widely used box constraints. The problem is formulated as a nonlinear programming problem in the General Algebraic Modeling System (GAMS) software and is solved by the CONOPT solver.
Bookmarks Related papers MentionsView impact
In this paper, a day-ahead energy management (EM) for isolated microgrids (MGs) is proposed to ob... more In this paper, a day-ahead energy management (EM) for isolated microgrids (MGs) is proposed to obtain the optimal dispatch such that the costs related to the fuel consumption of diesel generators, load shedding, and renewable energy curtailment are minimized. Usually, fuel consumption costs of diesel generators are considered to be dependent on active power generation only. However, neglecting the related reactive power costs might result in increased operation costs and deviations in the dispatches from the optimal solutions. Hence, this paper co-optimizes the costs related to both active and reactive powers of diesel generators. In addition, this study considers the reactive power capability of inverter-interfaced distributed energy resources (DERs). The energy management problem is formulated as a nonlinear programming problem in GAMS environment and is solved using the CONOPT solver. Four different cases are presented to show the effect of considering the reactive power costs of the diesel generators and the reactive power capability from the inverter-interfaced DERs on the operating costs and dispatch results of the isolated MG.
Bookmarks Related papers MentionsView impact
MEPCON Conference
Direct Torque Control (DTC) of AC drives is considered one of the most interesting high dynamic r... more Direct Torque Control (DTC) of AC drives is considered one of the most interesting high dynamic response motor control strategies nowadays. Permanent Magnet Synchronous Motors (PMSM) are now replacing Induction Motors (IM) in a variety of applications due to their valuable advantages like increased efficiency and compact size. The combination of DTC and PMSM in the same drive system leads to excellent performance not only for torque dynamics but also for efficiency point of view. DTC depends on the selection of the desired stator voltage vector from a look-up table called "switching selection table" to meet the torque and flux change requirements. In the literature, there are various switching tables according to the using of zero voltage vectors and the number of hysteresis comparator levels. Each table has its own merits and demerits in terms of torque response, speed response, torque and flux ripples and switching frequency (losses). Comparisons of these various switching tables are discussed in this paper showing their effect on the drive performance through MATLAB/Simulink simulations. Permanent Magnet Synchronous Motor (PMSM), Voltage Source Inverter (VSI), Switching Table, Matlab/Simulink.
Bookmarks Related papers MentionsView impact
Direct torque control (DTC) of AC drives is considered one of the most interesting high performa... more Direct torque control (DTC) of AC drives is considered one of the most interesting
high performance control techniques nowadays. Permanent magnet synchronous motors
(PMSM) are now replacing induction motors (IM) in a variety of applications due to
their valuable characteristics especially the increased efficiency and compact size. The
combination of DTC and PMSM in one drive system leads to high dynamic response
drive system that seems to be an interesting topic to gain the increased research in the
literature.
DTC offers high dynamic torque, flux, and speed responses better than that of Field
Oriented Control (FOC) technique with simple controller architecture that utilizes two
hysteresis controllers and a switching table to select the most suitable voltage vector to
meet the torque and flux requirements. No machine parameter dependences, no axes
transformation required, no voltage modulation techniques, and no current controllers
are the advantages of DTC over FOC. Comparisons between DTC and FOC of PMSM
are made through MATLAB simulations to show their characteristics with respect to
the other. It is found that DTC gives excellent dynamic responses in both torque and
flux but the ripple content is high.
DTC requires the estimation for both flux and torque. A lot of methods are found in
the literature to estimate the flux and the most powerful methods are compared via
simulations. Pure integration method of flux estimation is the basic method that has a
lot of demerits like offset, resistance variation dependence, initial value problem, and
low performance at low speeds. Low Pass Filter (LPF) is intended to solve the pure
integration problems but its performance at transient period is not good and there is
some drift in the flux beyond the actual flux. Modified integrator is also one of the
interesting flux estimation methods that gives better performance at both transient and
steady state conditions than that of LPF estimator but it contains PI controller and low
pass filters so that several tunings are required and complexity is increased. A flux
estimator uses tunable-cutoff-frequency-LPF is simple and accurate. It is used for IM
and never be used for PMSM. It is also compared and shows excellent results in both
transient and steady state periods which implies the effectiveness of it for PMSM as
well as IM.
Switching Look-up Table is a unique characteristic in a DTC drive and it has a lot of
schemes based on the number of hysteresis levels of the torque and flux comparators
and the inclusion / exclusion of the zero voltage vectors. Various switching tables
appeared in the literature are compared to judge the merits and demerits of each one
and to show their effect on the drive performance. A relatively new switching table
using modified definition of the flux sectors is used for PMSM for the first time and its
results are excellent because it avoids a fatal problem appeared in the table proposed by
Takahashi, the inventor of the DTC system.
Selection of the amplitude of the flux and torque hysteresis bands is a very
important issue in implementing the DTC drive system as they affect torque ripples,
flux distortion, switching losses, and current harmonics. Simulations are made to
show these effects. Trade off should be made to correctly choosing of the
hysteresis band amplitudes according to the performance requirements.
Torque / flux ripples and variable switching frequency are the main disadvantages of
DTC system. Solutions to these problems are an interesting researching aspect
nowadays. Increased number of voltage vectors and/or sectors, Space Vector
Modulation (SVM), Duty Ratio control, and Model Predictive Control (MPC)
techniques are the most common solutions to the problems of high ripple content and
variable switching frequency. The loss of the DTC simplicity is something that makes
these solutions inconvenient so that compromise studies should be done to select the
most suitable control technique that meets the application needs without increasing the
complexity of the system.
Digital Signal Processors (DSPs) are now considered the basic controllers used in
the motor control area. DSP programming is often done using hand written code by C
or Assembly languages which is very time consuming and very prone to errors.
Computer Aided Control System Design (CACSD) is some sort of block programming
can be implemented using Matlab/Simulink. The Simulink model itself can be
downloaded to the DSP which makes the real time control system design easier.
The complete description of the DTC-PMSM drive system is discussed showing the
power, control, measurement, and signal conditioning circuits used in the system. Six
step operation of the inverter as well as open loop V/F control of PMSM are
implemented in order to verify the effectiveness of the CACSD using Matlab/Simulink.
Bookmarks Related papers MentionsView impact
With the increasing interests on energy efficiency, energy cost, and environmental pro... more With the increasing interests on energy efficiency, energy cost, and environmental
protection, the development of electric vehicles (EVs) technology has been obvious
nowadays. Based on the air pollution regulations in the USA and Europe as well as a
lot of countries in the world, the fossil-fueled vehicles have been targeted as the major
source of emissions that create air po llution leading to the global warming crisis. The
oil resources in the earth are limited and the new discoveries of it are at a slower pace
than the increase in demand especially with the increase in the world population so
that the need for alternatives is becoming crucial.
The technologies involved in EVs are diversified and include electrical and
electronics engineering, mechanical engineering, automotive engineering, and
chemical engineering. EVs depend on which called electric propulsion, in which an
electric motor is used to drive the vehicle instead of the internal combustion engine
(ICE) and the energy sources are batteries, fuel cells, or capacitors instead of gasoline
or diesel fuel in the conventional ICE vehicles. Thus, power electronics technology
plays an important role in the electrical propulsion system in order to efficiently drive
the electric motor of the vehicle and control the power converters and the associated
electronic circuits.
An overview of the current status of power electronic drives for EVs and recent
research trends in EV motors, power converters, and energy storage systems will be
discussed. Challenges associated with designing, controlling, and operating the power
electronic converters used in EVs will be also discussed showing the latest
achievements in this field. Challenges and problems associated with power electronic
converters will be discussed also.
Bookmarks Related papers MentionsView impact