Nezar ALyazidi | King Fahd University of Petroleum and Minerals (original) (raw)

Papers by Nezar ALyazidi

Journal of Robotics and Control/Journal of Robotics and Control (JRC), Jan 30, 2024

International Journal of Robotics and Control Systems, Jun 11, 2023

With the intimate integration of power grids and cyber networks, limited bandwidth and packet del... more With the intimate integration of power grids and cyber networks, limited bandwidth and packet delay have a rapidly expanding negative impact on power system performance. The presented multi-area interconnected power system consists of four areas, each including thermal and hydro-generation plants. This paper investigates the stability analysis problem for cyber-physical systems with a round-robin communication protocol under mixed cyberattacks and load changes. The objective is to stabilize a multi-area interconnected power system (MAIPS) using a static feedback controller while minimizing the defined performance function. Then, the stability of the MAIPS is characterized when the system is subjected to a transmission delay while considering predetermined limits for the duration and the frequency of the delay. Our findings indicate that time delays can influence system stability and that choosing an appropriate sampling interval is necessary to ensure the stability of the system. Finally, an illustrative example of three areas of interconnected power systems with several scenarios is presented to verify the effectiveness of the proposed method. This is an open access article under the CC-BY-SA license. The standard control scheme of the LFC requires additional modifications to handle the new

Applied Mathematics and Computation, Jun 1, 2023

IEEE transactions on systems, man, and cybernetics, Mar 1, 2020

Distributed generation (DG) technology arises in several applications of power supply to tackle t... more Distributed generation (DG) technology arises in several applications of power supply to tackle the issues of increasing energy demands. The concept of microgrids is introduced to integrate the DG technology into utility power networks. This paper introduces a fuzzy control scheme for networked systems utilizing a quantized Hinfty{H}_{\infty }Hinfty estimator over communication networks for DGs subject random constraints. The developed estimation algorithm is worthy for ensuring the network stability and enduring any sort of quantization, time delay, and packet drops. In these senses, adequate conditions have been mainly derived by means of linear matrix inequalities. An illustrative examples are demonstrated to confirm the effectiveness of the meant design procedure.

Neurocomputing, 2018

This paper introduces novel cooperative control scheme based on adaptive critics for islanded Mic... more This paper introduces novel cooperative control scheme based on adaptive critics for islanded Microgrids in the presence of disturbances. The interactions between the distributed generation sources are governed by a communication graph. Synchronization ideas are used to couple the dynamics of the distributed generation sources. A utility function is selected to reflect the objectives of the optimization problem. An online adaptive learning technique based on particle filtering is developed to estimate the dynamics of the distributed generation sources. Once the separation principle is held, the control input of every generation source and the estimator can be designed independently. The online adaptive learning technique uses incomplete knowledge about the dynamics of the distributed generation sources. Means of adaptive critics are used to implement the solution in real-time.

Journal of The Franklin Institute-engineering and Applied Mathematics, Mar 1, 2017

We study the design problem of dynamic event-triggered (ET) fuzzy control methodology for discret... more We study the design problem of dynamic event-triggered (ET) fuzzy control methodology for discretetime Takagi-Sugeno (T-S) systems in this work. The observed-state error is utilized to derive the event condition. Sufficient condition for the asymptotic stability of the closed-loop fuzzy system and the observer error system under the event-triggered fuzzy control is provided by linear matrix inequality (LMI). Moreover, the corresponding self-triggered (ST) fuzzy control is developed where the following control action is estimated in terms of the current sampled data. Furthermore, simulations are given to represent the feasibility and efficiency of the achieved results. Index Terms Event-based control, self-triggered, discrete-time fuzzy systems. I. INTRODUCTION Recent employments of artificial intelligence (AI) approaches aimed to imitate human practice into a implementable code for processing by computers [1]. AI techniques paved the way to intelligent control by generating efficient advanced control methods. In general, intelligent systems are often characterized by: 1) Analogies with biological systems to build up dynamic models, 2) By exploring at how human actuality carries out control tasks to characterize course of actions, 3) Recognize patterns or make decisions to reach prescribed goals The disparity between humans and machines are readily obvious: humans persuade normally in uncertain, complicated methods. However, computers are mainly performing in terms of binary persuading. In this regard, the basic concept of fuzzy logic is an attempt to mimic human control logic thereby making machines immense intelligent, thus permissive them to persuade based on a fuzzy technique such humans. Fuzzy logic developed to be a powerful tool to handle uncertain, and inaccurate problems [2]. Dynamic systems based on fuzzy-logic representations are often called Takagi-Sugeno (T-S) systems. This class of fuzzy dynamic models consists of a group of models that carefully linked with fuzzy membership functions [3]. In particular, fuzzy logic method can be performed in the field of a real implementation using: 1) Fuzzification: adapt data into fuzzy data or membership functions (MFs). 2) Fuzzy Inference Process: integrate MFs with control laws to acquire the fuzzy output. 3) Defuzzification: calculate every related output and generate a look-up table. 4) Next, catch up the output from the look-up list by means of the present input. Prominent features of fuzzy-logic controllers (FLC) attributed to robustness properties, ease of modification and cheap to implement. A short survey on study and architecture methodologies of the T-S models is demonstrated in [4]. Stability and dissipativity conditions were obtained for the fuzzy schemes with nonuniform uncertain sampling

International Journal of Electrical Power & Energy Systems, Sep 1, 2017

This paper introduces a survey on the adaptive and intelligent methods that have been applied to ... more This paper introduces a survey on the adaptive and intelligent methods that have been applied to microgrids systems. Interestingly, the adaptive technique is effectively exercised in various control issues including stability, tracking error, and parameter uncertainties. Adaptive control has been extremely developed by using intelligent algorithms to automatically tune the control parameters namely fuzzy logic, particle swarm optimization, bacterial search algorithm, and etc. The objective is to evaluate and classify the design control methods and evaluation algorithms for the microgrid systems to maintain stability, reliability, and load variations by adjusting the controller parameters especially in standalone operation mode. The stability of islanded microgrids are constantly impacted by the related loads. A significant part of the research on an islanded microgrid involves droop control technique. In normal operation, distributed generation units and storage units provide power quality control. Once a shutdown is occurred, microgrid can be isolated from the main grid and operate in a local grid to support the local loads. Thus, distributed generations cooperate storage units to sustain the stability of the islanded microgrid.

International Journal of Robotics and Control Systems, Nov 28, 2022

A teleoperation system is referred to as a plant that is controlled remotely, and it is often com... more A teleoperation system is referred to as a plant that is controlled remotely, and it is often composed of a human operator, a local master manipulator, and a remote slave manipulator, all connected by a communication network. Bilateral teleoperation systems (BTOS) include transmissions in both the forward and backward directions between the master and slave. This paper discusses a class of (BTOS) focusing on the security of the system after modeling the master and slave robots mathematically. The false data injection attack is examined, where the attacker may inject false data into the states that are being exchanged between the master and slave robots. The vulnerability of BTOS, where the attack destabilizes the system, is presented. A deep learning-based detection technique is proposed to detect the presence of false data injection attacks. The deep learning model with convolution neural network structure is trained and tested with considering complex attacks where the attacker has full knowledge of the system and proficiency to emanate and control the target system. The proposed model achieves 96% validation accuracy, and the efficacy of the proposed deep learning detector is demonstrated and tested into the BTOS. This is an open access article under the CC-BY-SA license.

Abstract This chapter introduces a novel online adaptive learning distributed control approach fo... more Abstract This chapter introduces a novel online adaptive learning distributed control approach for a system of distributed generation units with disturbances in their dynamical environments. The interactions between the generation units are restricted by a graph topology, which means that the dynamics of the generation units are coupled. The coordination ideas or distributed synchronization protocols are utilized to maintain synchronization among the generation units. The cost function is designed to take into account the neighborhood interactions and the graph topology. Coupled Bellman optimality equations are developed for the distributed generation network. A distributed online reinforcement learning approach that employs a Kalman filter is employed to solve the optimal control problem of the multiagent system. This control approach is implemented in real time using neural network approximations and it does not need to know the full dynamics of the generation systems. The validity of the distributed control approach is tested using a system of distributed generation units working under disturbances.

Abstract This chapter presents a pilot-scale implementation of a two-level coordinating control a... more Abstract This chapter presents a pilot-scale implementation of a two-level coordinating control approach for the islanded operation of a microgrid system. In the islanded operation of the microgrid, the master distributed generation unit handles the voltage and frequency control of the load, and the slave distributed generation units regulate their power components on the basis of the use of the conventional dq-current control strategy. On the basis of the simulation environment within MATLAB/SimPowerSystems, three typical experimental studies including laboratory-scale devices and equipment were conducted. The ensuing results illustrate effective performance under the control strategy developed.

Applied Mathematics and Computation, Oct 1, 2019

This paper focuses on the behavior of a linear quadratic Gaussian (LQG) controller for discrete-t... more This paper focuses on the behavior of a linear quadratic Gaussian (LQG) controller for discrete-time systems utilizing industrial communication protocols. A new design of LQG problem is investigated for constrained networked control systems by using a new class of a quadratic cost function with a communication cost. This paper is considered two industrial communication protocols namely: the transportation control protocol (TCP), in which the sender should receive an acknowledgment regarding the delivery of the sending packets and the user datagram protocol (UDP) where the acknowledgment signal is absence. In the latter one, the driver (actuation) does not afford acknowledgment to inform the controller/estimator regarding the reception of the action packets. In such setting, the UDP-like protocol can react nonlinearly, where the absence of the acknowledgment creates a nonlinear optimization control law. In this sense, a LQG with standard Kalman filtering is failed because the separation principle can not reached. Under this setting, a suboptimal methodology can be successfully implemented to compensate the absence of communication and acknowledgment packets. The prescribed performance of networked system is sustained in the presence of communication constraints. The probabilities of the data signal dropouts are expressed in terms of random Bernoulli processes. Then, simulation results are provided to demonstrate the validity of the proposed schemes and to compare them with others from literature.

International Journal of Systems Science, Aug 13, 2018

ABSTRACT In this paper, we implement an output-feedback adaptive controller for islanded distribu... more ABSTRACT In this paper, we implement an output-feedback adaptive controller for islanded distributed generation systems (DGs) with communication, load and generation constraints. The adaptive controller is introduced to deal with nonlinearities of dynamical systems and unknown constraints. It primarily consists of a predictor, an adaptive law, and a control law. Herein, the controller can sustain desired performance and the robustness, in which the control law loop contains a low pass filter that sustain a rapid adaptation rate without fluctuations. The critical challenge into a standalone microgrid is to coordinate the necessitate load power with the distributed generations production in the presence of load/generation fluctuations. The coordinated controller is implemented to undertake the conflicts, and to enhance the performance, and to minimise the control cost by coordinate the requirements between decentralised controllers. The proposed controller is worthy for ensuring the network stability of DGs in a microgrid environment in the presence of uncertainties and transmission time delays. A typical simulation example is presented to confirm the effectiveness of the proposed design procedure.

IEEE Access

Sustaining the performance of the power grid at a desired operating point is a challenge in an un... more Sustaining the performance of the power grid at a desired operating point is a challenge in an uncertain environment. As a result of the environment's dynamic and unpredictable nature, the multi-arealinked power system is impacted by communication limitations and load variance. Due to the widespread nature of electricity, several power regions share information inside a communication network. In complex networks, connectivity restrictions, which include time delays, information loss, and restricted bandwidth, may impair the dependability and scalability of the control method. Variations in the load can affect the stability of the power systems. Due to the active load change and the dynamic environment and uncertainty, a model-free controller is a suitable technique that can maintain reliable performance in this condition. The online adaptive policy control scheme is proposed for load frequency control (LFC) challenges in single and multi-area power grids. The proposed scheme uses an optimal control approach through a modified Bellman equation and two neural networks, one to approximate the proposed solving value function and the second one to approximate the optimal control. The performance of the proposed model free adaptive control is compared with that of the model predictive control. INDEX TERMS Online adaptive, adaptive control, interconnected power systems. I. INTRODUCTION A. BACKGROUND AND MOTIVATIONS

IFAC Proceedings Volumes, 2012

International Journal of Robotics and Control Systems

With the intimate integration of power grids and cyber networks, limited bandwidth and packet del... more With the intimate integration of power grids and cyber networks, limited bandwidth and packet delay have a rapidly expanding negative impact on power system performance. The presented multi-area interconnected power system consists of four areas, each including thermal and hydro-generation plants. This paper investigates the stability analysis problem for cyber-physical systems with a round-robin communication protocol under mixed cyberattacks and load changes. The objective is to stabilize a multi-area interconnected power system (MAIPS) using a static feedback controller while minimizing the defined performance function. Then, the stability of the MAIPS is characterized when the system is subjected to a transmission delay while considering predetermined limits for the duration and the frequency of the delay. Our findings indicate that time delays can influence system stability and that choosing an appropriate sampling interval is necessary to ensure the stability of the system. Fi...

IEEE Access

This paper investigates an adaptive control problem for switched cyber-physical systems subject t... more This paper investigates an adaptive control problem for switched cyber-physical systems subject to external disturbances, denial-of-service (DoS) attacks, and false data injection attacks. We consider attackers to be able to threaten the networked system performance, where the DoS depletes the network bandwidth and might randomly block out the transmission signals or produce a significant delay in transmission signals, while the false data injections fabricate the transmission signal as a disturbance. To handle the abrupt occurrence of cyber attacks, the power system is modeled as a switched system. The switched system responds to changing dynamic models and among the states when the system parameters are altered due to disturbances, denial-of-service, and false data injection attacks. The proposed controller unit involves a reliable estimation scheme to estimate and compensate for cyber attacks while sustaining the desired performance and robustness. A distinctive feature of the proposed controller is the introduction of a low-pass filter, which is particularly convenient for attenuating parameter fluctuations and guaranteeing a rapid adaptation rate. The simulation of the closed loop system shows that the proposed L 1 controller outperforms the H ∞ controller. A simulation study is established to illustrate the influence and robustness of the developed controller, which can enhance the transient response under different operating conditions.

Applied Mathematics and Computation

The topic of this thesis is control and estimation over unreliable communication networks such as... more The topic of this thesis is control and estimation over unreliable communication networks such as wireless network. It is assumed that the plant and control unit are connected though unreliable channels. We considered the problems of estimation and control under two different protocols. In the TCP-like protocol, where the control unit provides acknowledgments successfully delivered of the packets, while the acknowledgments are absent in case of UDP-like protocol. This thesis investigates techniques for designing linear quadratic Gaussian LQG controller and estimation schemes subject to packet dropout using state and output feedback. Firstly, LQG optimal controller is designed using optimal theory based on Linear quadratic regulator and a discrete Kalman filter with packet dropout according to Bernoulli process. Necessary and sufficient conditions to guaranty stability are stated. Then estimation schemes are elaborated for a class of networked control system with nonstationary data lost. Two observer based stabilizing controller of networked control systems (NCSs) are designed in case of zero input and hold input strategies. Sufficient conditions for stability are dex rived in terms of using linear matrix inequality (LMIs). Theoretical analysis and simulation results are presented using MATLAB software for several numerical examples.

10th International Multi-Conferences on Systems, Signals & Devices 2013 (SSD13), 2013

Journal of Robotics and Control/Journal of Robotics and Control (JRC), Jan 30, 2024

International Journal of Robotics and Control Systems, Jun 11, 2023

With the intimate integration of power grids and cyber networks, limited bandwidth and packet del... more With the intimate integration of power grids and cyber networks, limited bandwidth and packet delay have a rapidly expanding negative impact on power system performance. The presented multi-area interconnected power system consists of four areas, each including thermal and hydro-generation plants. This paper investigates the stability analysis problem for cyber-physical systems with a round-robin communication protocol under mixed cyberattacks and load changes. The objective is to stabilize a multi-area interconnected power system (MAIPS) using a static feedback controller while minimizing the defined performance function. Then, the stability of the MAIPS is characterized when the system is subjected to a transmission delay while considering predetermined limits for the duration and the frequency of the delay. Our findings indicate that time delays can influence system stability and that choosing an appropriate sampling interval is necessary to ensure the stability of the system. Finally, an illustrative example of three areas of interconnected power systems with several scenarios is presented to verify the effectiveness of the proposed method. This is an open access article under the CC-BY-SA license. The standard control scheme of the LFC requires additional modifications to handle the new

Applied Mathematics and Computation, Jun 1, 2023

IEEE transactions on systems, man, and cybernetics, Mar 1, 2020

Distributed generation (DG) technology arises in several applications of power supply to tackle t... more Distributed generation (DG) technology arises in several applications of power supply to tackle the issues of increasing energy demands. The concept of microgrids is introduced to integrate the DG technology into utility power networks. This paper introduces a fuzzy control scheme for networked systems utilizing a quantized Hinfty{H}_{\infty }Hinfty estimator over communication networks for DGs subject random constraints. The developed estimation algorithm is worthy for ensuring the network stability and enduring any sort of quantization, time delay, and packet drops. In these senses, adequate conditions have been mainly derived by means of linear matrix inequalities. An illustrative examples are demonstrated to confirm the effectiveness of the meant design procedure.

Neurocomputing, 2018

This paper introduces novel cooperative control scheme based on adaptive critics for islanded Mic... more This paper introduces novel cooperative control scheme based on adaptive critics for islanded Microgrids in the presence of disturbances. The interactions between the distributed generation sources are governed by a communication graph. Synchronization ideas are used to couple the dynamics of the distributed generation sources. A utility function is selected to reflect the objectives of the optimization problem. An online adaptive learning technique based on particle filtering is developed to estimate the dynamics of the distributed generation sources. Once the separation principle is held, the control input of every generation source and the estimator can be designed independently. The online adaptive learning technique uses incomplete knowledge about the dynamics of the distributed generation sources. Means of adaptive critics are used to implement the solution in real-time.

Journal of The Franklin Institute-engineering and Applied Mathematics, Mar 1, 2017

We study the design problem of dynamic event-triggered (ET) fuzzy control methodology for discret... more We study the design problem of dynamic event-triggered (ET) fuzzy control methodology for discretetime Takagi-Sugeno (T-S) systems in this work. The observed-state error is utilized to derive the event condition. Sufficient condition for the asymptotic stability of the closed-loop fuzzy system and the observer error system under the event-triggered fuzzy control is provided by linear matrix inequality (LMI). Moreover, the corresponding self-triggered (ST) fuzzy control is developed where the following control action is estimated in terms of the current sampled data. Furthermore, simulations are given to represent the feasibility and efficiency of the achieved results. Index Terms Event-based control, self-triggered, discrete-time fuzzy systems. I. INTRODUCTION Recent employments of artificial intelligence (AI) approaches aimed to imitate human practice into a implementable code for processing by computers [1]. AI techniques paved the way to intelligent control by generating efficient advanced control methods. In general, intelligent systems are often characterized by: 1) Analogies with biological systems to build up dynamic models, 2) By exploring at how human actuality carries out control tasks to characterize course of actions, 3) Recognize patterns or make decisions to reach prescribed goals The disparity between humans and machines are readily obvious: humans persuade normally in uncertain, complicated methods. However, computers are mainly performing in terms of binary persuading. In this regard, the basic concept of fuzzy logic is an attempt to mimic human control logic thereby making machines immense intelligent, thus permissive them to persuade based on a fuzzy technique such humans. Fuzzy logic developed to be a powerful tool to handle uncertain, and inaccurate problems [2]. Dynamic systems based on fuzzy-logic representations are often called Takagi-Sugeno (T-S) systems. This class of fuzzy dynamic models consists of a group of models that carefully linked with fuzzy membership functions [3]. In particular, fuzzy logic method can be performed in the field of a real implementation using: 1) Fuzzification: adapt data into fuzzy data or membership functions (MFs). 2) Fuzzy Inference Process: integrate MFs with control laws to acquire the fuzzy output. 3) Defuzzification: calculate every related output and generate a look-up table. 4) Next, catch up the output from the look-up list by means of the present input. Prominent features of fuzzy-logic controllers (FLC) attributed to robustness properties, ease of modification and cheap to implement. A short survey on study and architecture methodologies of the T-S models is demonstrated in [4]. Stability and dissipativity conditions were obtained for the fuzzy schemes with nonuniform uncertain sampling

International Journal of Electrical Power & Energy Systems, Sep 1, 2017

This paper introduces a survey on the adaptive and intelligent methods that have been applied to ... more This paper introduces a survey on the adaptive and intelligent methods that have been applied to microgrids systems. Interestingly, the adaptive technique is effectively exercised in various control issues including stability, tracking error, and parameter uncertainties. Adaptive control has been extremely developed by using intelligent algorithms to automatically tune the control parameters namely fuzzy logic, particle swarm optimization, bacterial search algorithm, and etc. The objective is to evaluate and classify the design control methods and evaluation algorithms for the microgrid systems to maintain stability, reliability, and load variations by adjusting the controller parameters especially in standalone operation mode. The stability of islanded microgrids are constantly impacted by the related loads. A significant part of the research on an islanded microgrid involves droop control technique. In normal operation, distributed generation units and storage units provide power quality control. Once a shutdown is occurred, microgrid can be isolated from the main grid and operate in a local grid to support the local loads. Thus, distributed generations cooperate storage units to sustain the stability of the islanded microgrid.

International Journal of Robotics and Control Systems, Nov 28, 2022

A teleoperation system is referred to as a plant that is controlled remotely, and it is often com... more A teleoperation system is referred to as a plant that is controlled remotely, and it is often composed of a human operator, a local master manipulator, and a remote slave manipulator, all connected by a communication network. Bilateral teleoperation systems (BTOS) include transmissions in both the forward and backward directions between the master and slave. This paper discusses a class of (BTOS) focusing on the security of the system after modeling the master and slave robots mathematically. The false data injection attack is examined, where the attacker may inject false data into the states that are being exchanged between the master and slave robots. The vulnerability of BTOS, where the attack destabilizes the system, is presented. A deep learning-based detection technique is proposed to detect the presence of false data injection attacks. The deep learning model with convolution neural network structure is trained and tested with considering complex attacks where the attacker has full knowledge of the system and proficiency to emanate and control the target system. The proposed model achieves 96% validation accuracy, and the efficacy of the proposed deep learning detector is demonstrated and tested into the BTOS. This is an open access article under the CC-BY-SA license.

Abstract This chapter introduces a novel online adaptive learning distributed control approach fo... more Abstract This chapter introduces a novel online adaptive learning distributed control approach for a system of distributed generation units with disturbances in their dynamical environments. The interactions between the generation units are restricted by a graph topology, which means that the dynamics of the generation units are coupled. The coordination ideas or distributed synchronization protocols are utilized to maintain synchronization among the generation units. The cost function is designed to take into account the neighborhood interactions and the graph topology. Coupled Bellman optimality equations are developed for the distributed generation network. A distributed online reinforcement learning approach that employs a Kalman filter is employed to solve the optimal control problem of the multiagent system. This control approach is implemented in real time using neural network approximations and it does not need to know the full dynamics of the generation systems. The validity of the distributed control approach is tested using a system of distributed generation units working under disturbances.

Abstract This chapter presents a pilot-scale implementation of a two-level coordinating control a... more Abstract This chapter presents a pilot-scale implementation of a two-level coordinating control approach for the islanded operation of a microgrid system. In the islanded operation of the microgrid, the master distributed generation unit handles the voltage and frequency control of the load, and the slave distributed generation units regulate their power components on the basis of the use of the conventional dq-current control strategy. On the basis of the simulation environment within MATLAB/SimPowerSystems, three typical experimental studies including laboratory-scale devices and equipment were conducted. The ensuing results illustrate effective performance under the control strategy developed.

Applied Mathematics and Computation, Oct 1, 2019

This paper focuses on the behavior of a linear quadratic Gaussian (LQG) controller for discrete-t... more This paper focuses on the behavior of a linear quadratic Gaussian (LQG) controller for discrete-time systems utilizing industrial communication protocols. A new design of LQG problem is investigated for constrained networked control systems by using a new class of a quadratic cost function with a communication cost. This paper is considered two industrial communication protocols namely: the transportation control protocol (TCP), in which the sender should receive an acknowledgment regarding the delivery of the sending packets and the user datagram protocol (UDP) where the acknowledgment signal is absence. In the latter one, the driver (actuation) does not afford acknowledgment to inform the controller/estimator regarding the reception of the action packets. In such setting, the UDP-like protocol can react nonlinearly, where the absence of the acknowledgment creates a nonlinear optimization control law. In this sense, a LQG with standard Kalman filtering is failed because the separation principle can not reached. Under this setting, a suboptimal methodology can be successfully implemented to compensate the absence of communication and acknowledgment packets. The prescribed performance of networked system is sustained in the presence of communication constraints. The probabilities of the data signal dropouts are expressed in terms of random Bernoulli processes. Then, simulation results are provided to demonstrate the validity of the proposed schemes and to compare them with others from literature.

International Journal of Systems Science, Aug 13, 2018

ABSTRACT In this paper, we implement an output-feedback adaptive controller for islanded distribu... more ABSTRACT In this paper, we implement an output-feedback adaptive controller for islanded distributed generation systems (DGs) with communication, load and generation constraints. The adaptive controller is introduced to deal with nonlinearities of dynamical systems and unknown constraints. It primarily consists of a predictor, an adaptive law, and a control law. Herein, the controller can sustain desired performance and the robustness, in which the control law loop contains a low pass filter that sustain a rapid adaptation rate without fluctuations. The critical challenge into a standalone microgrid is to coordinate the necessitate load power with the distributed generations production in the presence of load/generation fluctuations. The coordinated controller is implemented to undertake the conflicts, and to enhance the performance, and to minimise the control cost by coordinate the requirements between decentralised controllers. The proposed controller is worthy for ensuring the network stability of DGs in a microgrid environment in the presence of uncertainties and transmission time delays. A typical simulation example is presented to confirm the effectiveness of the proposed design procedure.

IEEE Access

Sustaining the performance of the power grid at a desired operating point is a challenge in an un... more Sustaining the performance of the power grid at a desired operating point is a challenge in an uncertain environment. As a result of the environment's dynamic and unpredictable nature, the multi-arealinked power system is impacted by communication limitations and load variance. Due to the widespread nature of electricity, several power regions share information inside a communication network. In complex networks, connectivity restrictions, which include time delays, information loss, and restricted bandwidth, may impair the dependability and scalability of the control method. Variations in the load can affect the stability of the power systems. Due to the active load change and the dynamic environment and uncertainty, a model-free controller is a suitable technique that can maintain reliable performance in this condition. The online adaptive policy control scheme is proposed for load frequency control (LFC) challenges in single and multi-area power grids. The proposed scheme uses an optimal control approach through a modified Bellman equation and two neural networks, one to approximate the proposed solving value function and the second one to approximate the optimal control. The performance of the proposed model free adaptive control is compared with that of the model predictive control. INDEX TERMS Online adaptive, adaptive control, interconnected power systems. I. INTRODUCTION A. BACKGROUND AND MOTIVATIONS

IFAC Proceedings Volumes, 2012

International Journal of Robotics and Control Systems

With the intimate integration of power grids and cyber networks, limited bandwidth and packet del... more With the intimate integration of power grids and cyber networks, limited bandwidth and packet delay have a rapidly expanding negative impact on power system performance. The presented multi-area interconnected power system consists of four areas, each including thermal and hydro-generation plants. This paper investigates the stability analysis problem for cyber-physical systems with a round-robin communication protocol under mixed cyberattacks and load changes. The objective is to stabilize a multi-area interconnected power system (MAIPS) using a static feedback controller while minimizing the defined performance function. Then, the stability of the MAIPS is characterized when the system is subjected to a transmission delay while considering predetermined limits for the duration and the frequency of the delay. Our findings indicate that time delays can influence system stability and that choosing an appropriate sampling interval is necessary to ensure the stability of the system. Fi...

IEEE Access

This paper investigates an adaptive control problem for switched cyber-physical systems subject t... more This paper investigates an adaptive control problem for switched cyber-physical systems subject to external disturbances, denial-of-service (DoS) attacks, and false data injection attacks. We consider attackers to be able to threaten the networked system performance, where the DoS depletes the network bandwidth and might randomly block out the transmission signals or produce a significant delay in transmission signals, while the false data injections fabricate the transmission signal as a disturbance. To handle the abrupt occurrence of cyber attacks, the power system is modeled as a switched system. The switched system responds to changing dynamic models and among the states when the system parameters are altered due to disturbances, denial-of-service, and false data injection attacks. The proposed controller unit involves a reliable estimation scheme to estimate and compensate for cyber attacks while sustaining the desired performance and robustness. A distinctive feature of the proposed controller is the introduction of a low-pass filter, which is particularly convenient for attenuating parameter fluctuations and guaranteeing a rapid adaptation rate. The simulation of the closed loop system shows that the proposed L 1 controller outperforms the H ∞ controller. A simulation study is established to illustrate the influence and robustness of the developed controller, which can enhance the transient response under different operating conditions.

Applied Mathematics and Computation

The topic of this thesis is control and estimation over unreliable communication networks such as... more The topic of this thesis is control and estimation over unreliable communication networks such as wireless network. It is assumed that the plant and control unit are connected though unreliable channels. We considered the problems of estimation and control under two different protocols. In the TCP-like protocol, where the control unit provides acknowledgments successfully delivered of the packets, while the acknowledgments are absent in case of UDP-like protocol. This thesis investigates techniques for designing linear quadratic Gaussian LQG controller and estimation schemes subject to packet dropout using state and output feedback. Firstly, LQG optimal controller is designed using optimal theory based on Linear quadratic regulator and a discrete Kalman filter with packet dropout according to Bernoulli process. Necessary and sufficient conditions to guaranty stability are stated. Then estimation schemes are elaborated for a class of networked control system with nonstationary data lost. Two observer based stabilizing controller of networked control systems (NCSs) are designed in case of zero input and hold input strategies. Sufficient conditions for stability are dex rived in terms of using linear matrix inequality (LMIs). Theoretical analysis and simulation results are presented using MATLAB software for several numerical examples.

10th International Multi-Conferences on Systems, Signals & Devices 2013 (SSD13), 2013