This paper proposes a linear matrix inequality (LMI)-based fuzzy fast terminal sliding mode contr... more This paper proposes a linear matrix inequality (LMI)-based fuzzy fast terminal sliding mode control (FFTSM) approach for a multi-input multi-output (MIMO) system. This design aims to achieve the finite-time convergence of system trajectories to their desired values, while at the same time eliminating the chattering problem. Finite-time stability is proven using the Lyapunov theory and the control parameters are obtained using the LMI approach. The fuzzy logic approach is considered to fine tune the controller parameters and reduce the tracking error and control signal amplitude. The performance of the proposed approach is assessed using a simulation study of a direct current (DC) motor. The obtained results confirm the effectiveness of the proposed control design. Simplicity of the design, robustness, finite-time convergence, and chattering-free dynamics are among the features of the proposed approach.
This paper proposes a type-2 fuzzy controller for floating tension-leg platforms in wind turbines... more This paper proposes a type-2 fuzzy controller for floating tension-leg platforms in wind turbines. Its main objective is to stabilize and control offshore floating wind turbines exposed to oscillating motions. The proposed approach assumes that the dynamics of all units are completely unknown. The latter are approximated using the proposed Sugeno-based type-2 fuzzy approach. A nonlinear Kalman-based algorithm is developed for parameter optimization, and linear matrix inequalities are derived to analyze the system’s stability. For the fuzzy system, both rules and membership functions are optimized. Additionally, in the designed approach, the estimation error of the type-2 fuzzy approach is also considered in the stability analysis. The effectiveness and performance of the proposed approach is assessed using a simulation study of a tension leg platform subject to various disturbance modes.
The increased penetration of renewable energy sources (RESs) along with the rise in demand for wi... more The increased penetration of renewable energy sources (RESs) along with the rise in demand for wireless communication had led to the need to deploy cellular base stations powered by locally accessible RESs. Moreover, networks powered by renewable energy sources have the ability to reduce the costs of generating electricity, as well as greenhouse gas emissions, thus maintaining the quality of service (QoS). This paper examines the techno-economic feasibility of developing grid-tied solar photovoltaic (PV)/biomass generator (BG)-powered heterogeneous networks in Bangladesh, taking into account the dynamic characteristics of RESs and traffic. To guarantee QoS, each macro and micro-base station is supplied through a hybrid solar PV/BG coupled with enough energy storage devices. In contrast, pico and femto BSs are powered through standalone solar PV units due to their smaller power rating. A hybrid optimization model for electric renewables (HOMER)-based optimization algorithm is conside...
Air pollution is one of the major issues in urban management. City managers and planners pay a gr... more Air pollution is one of the major issues in urban management. City managers and planners pay a great deal of attention to this problem given its harmful effect on people’s health and the environment. This paper proposes a simulated model of the pollution level of the capital city of Tehran along with its source and outcomes based on system dynamics. First, it provides a comprehensive review of the sources of greenhouse emission along with the impact of natural factors on its growth. The data is collected from 2011 to 2021. Then a dynamic model is applied to simulate Tehran’s air pollution for twenty years (from 2011 to 2031). The statistical method of design of experiments (DoE) is considered to set the sensitive and controllable variables of the city’s pollution. The information is used to set plans to reduce the air pollution considering several scenarios. The results of the research show that the best strategy to reduce air pollution that can resolve other issues as well is to ma...
Endowing wind farms (WFs) with fault ride through (FRT) capability is crucial to their continuous... more Endowing wind farms (WFs) with fault ride through (FRT) capability is crucial to their continuous availability under various operating conditions. This paper proposes a dynamic adaptive multi-cell fault current limiter (MCFCL) topology to enhance the FRT capability of grid connected WFs. The proposed MCFCL consists of one transient cell (TC) and multi resistive cells (RCs) directly connected to the grid’s high voltage without using any series injection transformers nor any series connection of semiconductor switches. The transient cell of the MCFCL includes two transient limiting reactors (TLRs) to mitigate the transient fault current and limit the rate of change of the currents of the semiconductor switches during fault occurrence. The number of RCs in the MCFCL is determined based on voltage sag level. These latter are inserted in the fault path to provide an adaptive voltage sag compensation mechanism according to the voltage sag level. Assessment of the MCFCL under various sag c...
This paper develops an artificial neural network (ANN) model for steady-state two-phase flow pres... more This paper develops an artificial neural network (ANN) model for steady-state two-phase flow pressure drop estimation in pipelines. Mechanistic models are traditionally considered in pipeline flow modeling. However, their reliance on fundamental laws of physics can negatively impact their accuracy when dealing with large experimental data sets and various pipeline inclinations. Hence, ANN models prove to be highly accurate compared to mechanistic models. Dimensional analysis is used to derive a broad reservoir of dimensionless groups and form candidate inputs to the ANN model. Identifying the groups leading to the best correlation of the output variable requires a laborious and nonsystematic trial-and-error procedure. To circumvent this problem, genetic algorithms (GA) were considered to identify the best ANN input combination, thereby allowing a good prediction of steady-state two-phase flow pressure drop in pipelines with all inclinations. The sensitivity of the model accuracy to ...
This paper proposes a novel passivity cascade technique (PCT)-based control for nonlinear inverte... more This paper proposes a novel passivity cascade technique (PCT)-based control for nonlinear inverted pendulum systems. Its main objective is to stabilize the pendulum’s upward states despite uncertainties and exogenous disturbances. The proposed framework combines the estimation properties of radial basis function neural networks (RBFNs) with the passivity attributes of the cascade control framework. The unknown terms of the nonlinear system are estimated using an RBFN approximator. The performance of the closed-loop system is further enhanced by using the integral of angular position as a virtual state variable. The lumped uncertainties (NN—Neural Network approximation, external disturbances and parametric uncertainty) are compensated for by adding a robustifying adaptive rule-based signal to the PCT-based control. The boundedness of the states is confirmed using the passivity theorem. The performance of the proposed approach was assessed using a nonlinear inverted pendulum system un...
This work presents a nonlinear control approach to maximise the power extraction of wind energy c... more This work presents a nonlinear control approach to maximise the power extraction of wind energy conversion systems (WECSs) operating below their rated wind speeds. Due to nonlinearities associated with the dynamics of WECSs, the stochastic nature of wind, and the inevitable presence of faults in practice, developing reliable fault-tolerant control strategies to guarantee maximum power production of WECSs has always been considered important. A fault-tolerant fractional-order nonsingular terminal sliding mode control (FNTSMC) strategy to maximize the captured power of wind turbines (WT) subjected to actuator faults is developed. A nonsingular terminal sliding surface is proposed to ensure fast finite-time convergence, whereas the incorporation of fractional calculus in the controller enhances the convergence speed of system states and simultaneously suppresses chattering, resulting in extracted power maximisation by precisely tracking the optimum rotor speed. Closed-loop stability is...
This paper proposes an adaptive fault tolerant control (FTC) design for a variable speed wind tur... more This paper proposes an adaptive fault tolerant control (FTC) design for a variable speed wind turbine (WT) operating in the high wind speeds region. It aims at mitigating pitch actuator faults and regulating the generator power to its rated value, thereby reducing the mechanical stress in the high wind speeds region. The proposed FTC design implements a sliding mode control (SMC) approach with an adaptation law that estimates the upper bounds of the uncertainties. System stability and uniform boundedness of the outputs was proven using the Lyapunov stability theory. The proposed approach was validated on a 5 MW three-blade wind turbine modeled using the National Renewable Energy Laboratory’s (NREL) Fatigue, Aerodynamics, Structures and Turbulence (FAST) wind turbine simulator. The controller’s performance was assessed in the presence of several pitch actuator faults and turbulent wind conditions. Its performance was also compared to that of a standard SMC approach. Mitigation of bla...
This paper proposes a linear matrix inequality (LMI)-based fuzzy fast terminal sliding mode contr... more This paper proposes a linear matrix inequality (LMI)-based fuzzy fast terminal sliding mode control (FFTSM) approach for a multi-input multi-output (MIMO) system. This design aims to achieve the finite-time convergence of system trajectories to their desired values, while at the same time eliminating the chattering problem. Finite-time stability is proven using the Lyapunov theory and the control parameters are obtained using the LMI approach. The fuzzy logic approach is considered to fine tune the controller parameters and reduce the tracking error and control signal amplitude. The performance of the proposed approach is assessed using a simulation study of a direct current (DC) motor. The obtained results confirm the effectiveness of the proposed control design. Simplicity of the design, robustness, finite-time convergence, and chattering-free dynamics are among the features of the proposed approach.
This paper proposes a type-2 fuzzy controller for floating tension-leg platforms in wind turbines... more This paper proposes a type-2 fuzzy controller for floating tension-leg platforms in wind turbines. Its main objective is to stabilize and control offshore floating wind turbines exposed to oscillating motions. The proposed approach assumes that the dynamics of all units are completely unknown. The latter are approximated using the proposed Sugeno-based type-2 fuzzy approach. A nonlinear Kalman-based algorithm is developed for parameter optimization, and linear matrix inequalities are derived to analyze the system’s stability. For the fuzzy system, both rules and membership functions are optimized. Additionally, in the designed approach, the estimation error of the type-2 fuzzy approach is also considered in the stability analysis. The effectiveness and performance of the proposed approach is assessed using a simulation study of a tension leg platform subject to various disturbance modes.
The increased penetration of renewable energy sources (RESs) along with the rise in demand for wi... more The increased penetration of renewable energy sources (RESs) along with the rise in demand for wireless communication had led to the need to deploy cellular base stations powered by locally accessible RESs. Moreover, networks powered by renewable energy sources have the ability to reduce the costs of generating electricity, as well as greenhouse gas emissions, thus maintaining the quality of service (QoS). This paper examines the techno-economic feasibility of developing grid-tied solar photovoltaic (PV)/biomass generator (BG)-powered heterogeneous networks in Bangladesh, taking into account the dynamic characteristics of RESs and traffic. To guarantee QoS, each macro and micro-base station is supplied through a hybrid solar PV/BG coupled with enough energy storage devices. In contrast, pico and femto BSs are powered through standalone solar PV units due to their smaller power rating. A hybrid optimization model for electric renewables (HOMER)-based optimization algorithm is conside...
Air pollution is one of the major issues in urban management. City managers and planners pay a gr... more Air pollution is one of the major issues in urban management. City managers and planners pay a great deal of attention to this problem given its harmful effect on people’s health and the environment. This paper proposes a simulated model of the pollution level of the capital city of Tehran along with its source and outcomes based on system dynamics. First, it provides a comprehensive review of the sources of greenhouse emission along with the impact of natural factors on its growth. The data is collected from 2011 to 2021. Then a dynamic model is applied to simulate Tehran’s air pollution for twenty years (from 2011 to 2031). The statistical method of design of experiments (DoE) is considered to set the sensitive and controllable variables of the city’s pollution. The information is used to set plans to reduce the air pollution considering several scenarios. The results of the research show that the best strategy to reduce air pollution that can resolve other issues as well is to ma...
Endowing wind farms (WFs) with fault ride through (FRT) capability is crucial to their continuous... more Endowing wind farms (WFs) with fault ride through (FRT) capability is crucial to their continuous availability under various operating conditions. This paper proposes a dynamic adaptive multi-cell fault current limiter (MCFCL) topology to enhance the FRT capability of grid connected WFs. The proposed MCFCL consists of one transient cell (TC) and multi resistive cells (RCs) directly connected to the grid’s high voltage without using any series injection transformers nor any series connection of semiconductor switches. The transient cell of the MCFCL includes two transient limiting reactors (TLRs) to mitigate the transient fault current and limit the rate of change of the currents of the semiconductor switches during fault occurrence. The number of RCs in the MCFCL is determined based on voltage sag level. These latter are inserted in the fault path to provide an adaptive voltage sag compensation mechanism according to the voltage sag level. Assessment of the MCFCL under various sag c...
This paper develops an artificial neural network (ANN) model for steady-state two-phase flow pres... more This paper develops an artificial neural network (ANN) model for steady-state two-phase flow pressure drop estimation in pipelines. Mechanistic models are traditionally considered in pipeline flow modeling. However, their reliance on fundamental laws of physics can negatively impact their accuracy when dealing with large experimental data sets and various pipeline inclinations. Hence, ANN models prove to be highly accurate compared to mechanistic models. Dimensional analysis is used to derive a broad reservoir of dimensionless groups and form candidate inputs to the ANN model. Identifying the groups leading to the best correlation of the output variable requires a laborious and nonsystematic trial-and-error procedure. To circumvent this problem, genetic algorithms (GA) were considered to identify the best ANN input combination, thereby allowing a good prediction of steady-state two-phase flow pressure drop in pipelines with all inclinations. The sensitivity of the model accuracy to ...
This paper proposes a novel passivity cascade technique (PCT)-based control for nonlinear inverte... more This paper proposes a novel passivity cascade technique (PCT)-based control for nonlinear inverted pendulum systems. Its main objective is to stabilize the pendulum’s upward states despite uncertainties and exogenous disturbances. The proposed framework combines the estimation properties of radial basis function neural networks (RBFNs) with the passivity attributes of the cascade control framework. The unknown terms of the nonlinear system are estimated using an RBFN approximator. The performance of the closed-loop system is further enhanced by using the integral of angular position as a virtual state variable. The lumped uncertainties (NN—Neural Network approximation, external disturbances and parametric uncertainty) are compensated for by adding a robustifying adaptive rule-based signal to the PCT-based control. The boundedness of the states is confirmed using the passivity theorem. The performance of the proposed approach was assessed using a nonlinear inverted pendulum system un...
This work presents a nonlinear control approach to maximise the power extraction of wind energy c... more This work presents a nonlinear control approach to maximise the power extraction of wind energy conversion systems (WECSs) operating below their rated wind speeds. Due to nonlinearities associated with the dynamics of WECSs, the stochastic nature of wind, and the inevitable presence of faults in practice, developing reliable fault-tolerant control strategies to guarantee maximum power production of WECSs has always been considered important. A fault-tolerant fractional-order nonsingular terminal sliding mode control (FNTSMC) strategy to maximize the captured power of wind turbines (WT) subjected to actuator faults is developed. A nonsingular terminal sliding surface is proposed to ensure fast finite-time convergence, whereas the incorporation of fractional calculus in the controller enhances the convergence speed of system states and simultaneously suppresses chattering, resulting in extracted power maximisation by precisely tracking the optimum rotor speed. Closed-loop stability is...
This paper proposes an adaptive fault tolerant control (FTC) design for a variable speed wind tur... more This paper proposes an adaptive fault tolerant control (FTC) design for a variable speed wind turbine (WT) operating in the high wind speeds region. It aims at mitigating pitch actuator faults and regulating the generator power to its rated value, thereby reducing the mechanical stress in the high wind speeds region. The proposed FTC design implements a sliding mode control (SMC) approach with an adaptation law that estimates the upper bounds of the uncertainties. System stability and uniform boundedness of the outputs was proven using the Lyapunov stability theory. The proposed approach was validated on a 5 MW three-blade wind turbine modeled using the National Renewable Energy Laboratory’s (NREL) Fatigue, Aerodynamics, Structures and Turbulence (FAST) wind turbine simulator. The controller’s performance was assessed in the presence of several pitch actuator faults and turbulent wind conditions. Its performance was also compared to that of a standard SMC approach. Mitigation of bla...
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