Wind turbines and photovoltaic arrays are the most prominent and widely used intermittent Distrib... more Wind turbines and photovoltaic arrays are the most prominent and widely used intermittent Distributed Generations (DGs). Due to the right-of-way, environmental, economical and other restrictions, the connection of this type of DGs to the preferred point of the distribution network is very difficult or in some cases impossible. Therefore, because of non-optimal locations, they may cause a voltage rise at the Points of Common Coupling (PCCs). In this paper, a coordinated design of Switchable Capacitor Banks (SCBs) with dynamic reconfiguration of the distribution network is proposed to avoid low and high voltage violations. For this purpose, distribution network reconfiguration is implemented to mitigate voltage rise at PCCs and Capacitor Banks (CBs) to solve the low voltage problem. A novel method is presented for determining the optimal size of CBs. The proposed Capacitor Sizing Method (CSM) effectively determines the optimal values of reactive power for the given nodes. The optimal locations of SCB are determined using particle swarm optimization algorithm. The 24-hour reactive power curve optimized by the proposed method plays a pivotal role in designing SCBs. The simulation results show that the implementation of the dynamic network reconfiguration and SCBs placement is required to maintain a standard voltage profile for better employment of DG embedded distribution networks.
Purpose An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands... more Purpose An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands of multi-input multi-output (MIMO) antenna. These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the impedance bandwidth (IBW) of the MIMO antenna, and its diligent adjustment of it leads to cover the frequency range of Bluetooth and Wireless Local Area Network systems. Design/methodology/approach A new MIMO antenna is introduced in this paper in conjunction with an enhanced Wilkinson power divider feeding platform. Findings These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the IBW of the MIMO antenna, and its diligent adjustment leads to covering the frequency range of Bluetooth and WLAN systems. Originality/value The proposed MIMO antenna benefits from good isolation between ports for both frequency bands. Th...
2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014
In this paper, an active damping control scheme using the PR (proportional and resonant) regulato... more In this paper, an active damping control scheme using the PR (proportional and resonant) regulator is proposed to eliminate the resonance for the grid-connected T-type three-level PWM converter systems with LLCL filter by which the total inductance can be reduced compared with the conventional LCL filters. The simulation results have verified the validity of the proposed control algorithm for a 25-kW three-phase T-type converter.
This work deals with minimizing fluctuations of propulsion force and improving the motion quality... more This work deals with minimizing fluctuations of propulsion force and improving the motion quality in a linear switched reluctance motor. In order to minimize the jerks in the moving part of the motor, a new profile has been used to generate an appropriate reference speed profile. The results indicate that at speed 0.5 m/s, the motor reaches its command speed at the proposed time while, using conventional speed profile it takes almost 1.4 times the desired time. In order to control the speed and incease the motion quality, a simple fuzzy logic system has been used which is able to overcome the uncertainties problem in nonlinear systems. The fuzzy control system can regulate the motor performance so that it tracks the reference speed with minimum error and fluctuation. To illustrate the performance of the fuzzy method, a conventional PI method along with a model reference adaptive control (MRAC) strategy have been applied to the motor and the obtained results for three control methods...
2015 9th International Conference on Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015
In this paper, an active damping control scheme based on virtual resistors is proposed for LLCL f... more In this paper, an active damping control scheme based on virtual resistors is proposed for LLCL filters in the single-phase grid inverters. In comparison with the well-known LCL filters, a very small-size inductor is inserted in series with the filter capacitor, by which the series resonance at the switching frequency may occur. By the LC filter branch, the switching ripple in the grid-side current is suppressed, from which the inductor size in the grid side is minimized. However, the resonance phenomena in this filter may also occur, which needs to be investigated to guarantee the system stability. A resonance suppression scheme based on virtual resistors is proposed for LLCL filters in single-phase grid inverters. The simulation results for a 3-kW single-phase system have verified the effectiveness of the proposed control scheme.
Background and Objectives: Different energy demand calls the need for utilizing Energy Hub System... more Background and Objectives: Different energy demand calls the need for utilizing Energy Hub Systems (EHS), but the economic dispatch issue has become complicated due to uncertainty in demand. So, scenario generation and reduction techniques are used to considering the uncertainty of the EH demand. Dependent on the amount of fuel used, each system has various generation costs. Configuration selection stands as a challenging dilemma in the EHS designing besides economic problems. In this paper, the optimal EHS operation along with configuration issue is tackled. Methods: To do so, two EHS types are investigated to evaluate the configuration effect besides energy prices simultaneously change. Typically, the effect of the Demand Response (DR) feature is rarely considered in EHSs management which considered in this paper. Also, Metaheuristic Automatic Data Clustering (MADC) is used to reduce the decision-making problem dimension instead of using human decision makers in the subject of clu...
This paper presents a control algorithm that minimizes the DC-link capacitance by decreasing the ... more This paper presents a control algorithm that minimizes the DC-link capacitance by decreasing the capacitor current. The capacitor current can be nullified by a feedback compensation term which is calculated from the power balance in the AC/DC converter. As a result, voltage variation in the DC-link is reduced further, which makes a large reduction in the size of DC-link capacitors which are expensive and have limitations in life time. Simulations are performed with two 80uF DC-link capacitors, which can be replaced by film capacitors.
This paper surveys recent works in line impedance estimation. Inverters used in distribution syst... more This paper surveys recent works in line impedance estimation. Inverters used in distribution system are often connected to the grid through LCL filter. Different methods are investigated for estimating the line impedance. Advantages and disadvantages with brief summary for each method are presented. Simulation results for a specified grid are shown for two main different methods and the results are compared with estimation error.
2014 IEEE Energy Conversion Congress and Exposition (ECCE), 2014
This paper proposes an active damping control scheme of the LLCL filters for the grid-connected t... more This paper proposes an active damping control scheme of the LLCL filters for the grid-connected three-level PWM converters, which is based on the virtual resistor concept. The LLCL filter structure consists of connecting a small inductor in series with the capacitor in the conventional LCL filters, which can attenuate the switching-frequency-related current ripples more effectively than the LCL filters, resulting in a significant reduction in the grid-side inductor size. However, the resonance phenomenon is still an issue to solve in this filter. By adding a virtual resistor, the resonance can be damped out, which is less dependent on the variation of the grid impedance. The simulation and experimental results have verified the effectiveness of the proposed scheme for three-phase T-type AC/DC PWM converter.
Abstract In this paper, allocation of hybrid photovoltaic panels, wind turbines and battery stora... more Abstract In this paper, allocation of hybrid photovoltaic panels, wind turbines and battery storage (PV/WT/BA) system in distribution network is presented aimed active losses cost minimization, voltage profile enhancement and minimizing power purchased from the hybrid system by the network. Meta-heuristic improved whale optimizer algorithm (IWOA) is used to determine the optimal location and size of the PV/WT/BA system components as decision variables. The conventional WOA is inspired by social behavior and the hunting of humpback whales and in this study its performance is improved by using crossover and mutation operators of differential evolution (DE) method to avoid getting caught in local optimal and reinforcement to achieve global optimal. The methodology is implemented on IEEE 33 bus network considering seasonal variations. The results indicated that optimal determination of the decision variables in the network minimizes the active losses cost, voltage deviations and cost of power purchased from the hybrid system by the network using IWOA. The superiority of the IWOA is confirmed in benchmark test functions solution with very competitive results and also better results in statistic analysis and higher convergence speed and accuracy in comparison with the WOA, DE and particle swarm optimization (PSO). Also the results showed that the highest losses and better voltage are related to the summer and the lowest values are obtained in autumn season. The solar panels only participate in energy generation in spring and summer seasons, cost of power purchased by the network is highest in summer and lowest in autumn season. Moreover, the network is placed in stable current and voltage condition and the network power losses and voltage deviations are minimized.
A combination of various energy conversion units offers a multi-carrier energy system, namely Ene... more A combination of various energy conversion units offers a multi-carrier energy system, namely Energy Hub (EH). Optimal scheduling of EHs in the interconnected systems besides providing flexible man...
Purpose At first, the organic/inorganic and hybrid PV materials by their electrical model are des... more Purpose At first, the organic/inorganic and hybrid PV materials by their electrical model are described. Then the proposed converter topology, circuit analysis and various operating modes of converter according to on/off timing of switches are investigated. The current and voltage in the converter components are illustrated and the voltage gain and switching stress of proposed converter are presented. Finally, to show the effectiveness of the proposed converter, the power loss analysis is provided and the simulation is done in PSIM software. In the last section, the advantages of the proposed topology of higher efficiency by lower number of components in compare with other conventional topologies are presented. Design/methodology/approach In this paper, an improved topology of DC-DC converter based on VL technique is proposed for Perovskite Solar cells (PeSCs). The PeSCs attracted a lot of interest due to their potential in combining the advantages of both organic and inorganic comp...
International Journal of Communication Systems, 2020
Along with expansion in using of Internet and computer networks, the privacy, integrity, and acce... more Along with expansion in using of Internet and computer networks, the privacy, integrity, and access to digital resources have been faced with permanent risks. Due to the unpredictable behavior of network, the nonlinear nature of intrusion attempts, and the vast number of features in the problem environment, intrusion detection system (IDS) is regarded as the main problem in the security of computer networks. A feature selection technique helps to reduce complexity in terms of both the executive load and the storage by selecting the optimal subset of features. The purpose of this study is to identify important and key features in building an IDS. To improve the performance of IDS, this paper proposes an IDS that its features are optimally selected using a new hybrid method based on fruit fly algorithm (FFA) and ant lion optimizer (ALO) algorithm. The simulation results on the dataset KDD Cup99, NSL-KDD, and UNSW-NB15 have shown that the FFA-ALO has an acceptable performance according to the evaluation criteria such as accuracy and sensitivity than previous approaches.
This study presents a new control system for a linear switched reluctance motor (LSRM). Type-2 Ta... more This study presents a new control system for a linear switched reluctance motor (LSRM). Type-2 Takati-Sugeno fuzzy system is used for the motor approximation. The uncertain parameters of the motor are described by the lower and upper membership functions. By constructing an integral sliding mode surface, an adaptive sliding mode controller is designed and dynamic stability of the sliding motion is verified using the Lyapunov function. The design of the proposed sliding mode surface is independent of the number of fuzzy rules and thus, computational complexity is significantly decreased. The control system is implemented on a double-sided four-phase LSRM and its performance is demonstrated by means of modelling and experimental results.
In this paper, an active damping control scheme for LLCL filters based on the PR (proportional-re... more In this paper, an active damping control scheme for LLCL filters based on the PR (proportional-resonant) regulator is proposed for grid-connected three-level T-type PWM converter systems. The PR controller gives an infinite gain at the resonance frequency. As a result, the oscillation can be suppressed at that frequency. In order to improve the stability of the system in the case of grid impedance variations, online grid impedance estimation is applied. Simulation and experimental results have verified the effectiveness of the proposed scheme for three-phase T-type AC/DC PWM converters.
Wind turbines and photovoltaic arrays are the most prominent and widely used intermittent Distrib... more Wind turbines and photovoltaic arrays are the most prominent and widely used intermittent Distributed Generations (DGs). Due to the right-of-way, environmental, economical and other restrictions, the connection of this type of DGs to the preferred point of the distribution network is very difficult or in some cases impossible. Therefore, because of non-optimal locations, they may cause a voltage rise at the Points of Common Coupling (PCCs). In this paper, a coordinated design of Switchable Capacitor Banks (SCBs) with dynamic reconfiguration of the distribution network is proposed to avoid low and high voltage violations. For this purpose, distribution network reconfiguration is implemented to mitigate voltage rise at PCCs and Capacitor Banks (CBs) to solve the low voltage problem. A novel method is presented for determining the optimal size of CBs. The proposed Capacitor Sizing Method (CSM) effectively determines the optimal values of reactive power for the given nodes. The optimal locations of SCB are determined using particle swarm optimization algorithm. The 24-hour reactive power curve optimized by the proposed method plays a pivotal role in designing SCBs. The simulation results show that the implementation of the dynamic network reconfiguration and SCBs placement is required to maintain a standard voltage profile for better employment of DG embedded distribution networks.
Purpose An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands... more Purpose An Elephant trunk shape (ETS) radiating element is used to achieve the two covering bands of multi-input multi-output (MIMO) antenna. These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the impedance bandwidth (IBW) of the MIMO antenna, and its diligent adjustment of it leads to cover the frequency range of Bluetooth and Wireless Local Area Network systems. Design/methodology/approach A new MIMO antenna is introduced in this paper in conjunction with an enhanced Wilkinson power divider feeding platform. Findings These frequency bands can be controlled by the length of a slot embedded in ETS. The slot length in ETS plays a defining role in controlling the IBW of the MIMO antenna, and its diligent adjustment leads to covering the frequency range of Bluetooth and WLAN systems. Originality/value The proposed MIMO antenna benefits from good isolation between ports for both frequency bands. Th...
2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014
In this paper, an active damping control scheme using the PR (proportional and resonant) regulato... more In this paper, an active damping control scheme using the PR (proportional and resonant) regulator is proposed to eliminate the resonance for the grid-connected T-type three-level PWM converter systems with LLCL filter by which the total inductance can be reduced compared with the conventional LCL filters. The simulation results have verified the validity of the proposed control algorithm for a 25-kW three-phase T-type converter.
This work deals with minimizing fluctuations of propulsion force and improving the motion quality... more This work deals with minimizing fluctuations of propulsion force and improving the motion quality in a linear switched reluctance motor. In order to minimize the jerks in the moving part of the motor, a new profile has been used to generate an appropriate reference speed profile. The results indicate that at speed 0.5 m/s, the motor reaches its command speed at the proposed time while, using conventional speed profile it takes almost 1.4 times the desired time. In order to control the speed and incease the motion quality, a simple fuzzy logic system has been used which is able to overcome the uncertainties problem in nonlinear systems. The fuzzy control system can regulate the motor performance so that it tracks the reference speed with minimum error and fluctuation. To illustrate the performance of the fuzzy method, a conventional PI method along with a model reference adaptive control (MRAC) strategy have been applied to the motor and the obtained results for three control methods...
2015 9th International Conference on Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015
In this paper, an active damping control scheme based on virtual resistors is proposed for LLCL f... more In this paper, an active damping control scheme based on virtual resistors is proposed for LLCL filters in the single-phase grid inverters. In comparison with the well-known LCL filters, a very small-size inductor is inserted in series with the filter capacitor, by which the series resonance at the switching frequency may occur. By the LC filter branch, the switching ripple in the grid-side current is suppressed, from which the inductor size in the grid side is minimized. However, the resonance phenomena in this filter may also occur, which needs to be investigated to guarantee the system stability. A resonance suppression scheme based on virtual resistors is proposed for LLCL filters in single-phase grid inverters. The simulation results for a 3-kW single-phase system have verified the effectiveness of the proposed control scheme.
Background and Objectives: Different energy demand calls the need for utilizing Energy Hub System... more Background and Objectives: Different energy demand calls the need for utilizing Energy Hub Systems (EHS), but the economic dispatch issue has become complicated due to uncertainty in demand. So, scenario generation and reduction techniques are used to considering the uncertainty of the EH demand. Dependent on the amount of fuel used, each system has various generation costs. Configuration selection stands as a challenging dilemma in the EHS designing besides economic problems. In this paper, the optimal EHS operation along with configuration issue is tackled. Methods: To do so, two EHS types are investigated to evaluate the configuration effect besides energy prices simultaneously change. Typically, the effect of the Demand Response (DR) feature is rarely considered in EHSs management which considered in this paper. Also, Metaheuristic Automatic Data Clustering (MADC) is used to reduce the decision-making problem dimension instead of using human decision makers in the subject of clu...
This paper presents a control algorithm that minimizes the DC-link capacitance by decreasing the ... more This paper presents a control algorithm that minimizes the DC-link capacitance by decreasing the capacitor current. The capacitor current can be nullified by a feedback compensation term which is calculated from the power balance in the AC/DC converter. As a result, voltage variation in the DC-link is reduced further, which makes a large reduction in the size of DC-link capacitors which are expensive and have limitations in life time. Simulations are performed with two 80uF DC-link capacitors, which can be replaced by film capacitors.
This paper surveys recent works in line impedance estimation. Inverters used in distribution syst... more This paper surveys recent works in line impedance estimation. Inverters used in distribution system are often connected to the grid through LCL filter. Different methods are investigated for estimating the line impedance. Advantages and disadvantages with brief summary for each method are presented. Simulation results for a specified grid are shown for two main different methods and the results are compared with estimation error.
2014 IEEE Energy Conversion Congress and Exposition (ECCE), 2014
This paper proposes an active damping control scheme of the LLCL filters for the grid-connected t... more This paper proposes an active damping control scheme of the LLCL filters for the grid-connected three-level PWM converters, which is based on the virtual resistor concept. The LLCL filter structure consists of connecting a small inductor in series with the capacitor in the conventional LCL filters, which can attenuate the switching-frequency-related current ripples more effectively than the LCL filters, resulting in a significant reduction in the grid-side inductor size. However, the resonance phenomenon is still an issue to solve in this filter. By adding a virtual resistor, the resonance can be damped out, which is less dependent on the variation of the grid impedance. The simulation and experimental results have verified the effectiveness of the proposed scheme for three-phase T-type AC/DC PWM converter.
Abstract In this paper, allocation of hybrid photovoltaic panels, wind turbines and battery stora... more Abstract In this paper, allocation of hybrid photovoltaic panels, wind turbines and battery storage (PV/WT/BA) system in distribution network is presented aimed active losses cost minimization, voltage profile enhancement and minimizing power purchased from the hybrid system by the network. Meta-heuristic improved whale optimizer algorithm (IWOA) is used to determine the optimal location and size of the PV/WT/BA system components as decision variables. The conventional WOA is inspired by social behavior and the hunting of humpback whales and in this study its performance is improved by using crossover and mutation operators of differential evolution (DE) method to avoid getting caught in local optimal and reinforcement to achieve global optimal. The methodology is implemented on IEEE 33 bus network considering seasonal variations. The results indicated that optimal determination of the decision variables in the network minimizes the active losses cost, voltage deviations and cost of power purchased from the hybrid system by the network using IWOA. The superiority of the IWOA is confirmed in benchmark test functions solution with very competitive results and also better results in statistic analysis and higher convergence speed and accuracy in comparison with the WOA, DE and particle swarm optimization (PSO). Also the results showed that the highest losses and better voltage are related to the summer and the lowest values are obtained in autumn season. The solar panels only participate in energy generation in spring and summer seasons, cost of power purchased by the network is highest in summer and lowest in autumn season. Moreover, the network is placed in stable current and voltage condition and the network power losses and voltage deviations are minimized.
A combination of various energy conversion units offers a multi-carrier energy system, namely Ene... more A combination of various energy conversion units offers a multi-carrier energy system, namely Energy Hub (EH). Optimal scheduling of EHs in the interconnected systems besides providing flexible man...
Purpose At first, the organic/inorganic and hybrid PV materials by their electrical model are des... more Purpose At first, the organic/inorganic and hybrid PV materials by their electrical model are described. Then the proposed converter topology, circuit analysis and various operating modes of converter according to on/off timing of switches are investigated. The current and voltage in the converter components are illustrated and the voltage gain and switching stress of proposed converter are presented. Finally, to show the effectiveness of the proposed converter, the power loss analysis is provided and the simulation is done in PSIM software. In the last section, the advantages of the proposed topology of higher efficiency by lower number of components in compare with other conventional topologies are presented. Design/methodology/approach In this paper, an improved topology of DC-DC converter based on VL technique is proposed for Perovskite Solar cells (PeSCs). The PeSCs attracted a lot of interest due to their potential in combining the advantages of both organic and inorganic comp...
International Journal of Communication Systems, 2020
Along with expansion in using of Internet and computer networks, the privacy, integrity, and acce... more Along with expansion in using of Internet and computer networks, the privacy, integrity, and access to digital resources have been faced with permanent risks. Due to the unpredictable behavior of network, the nonlinear nature of intrusion attempts, and the vast number of features in the problem environment, intrusion detection system (IDS) is regarded as the main problem in the security of computer networks. A feature selection technique helps to reduce complexity in terms of both the executive load and the storage by selecting the optimal subset of features. The purpose of this study is to identify important and key features in building an IDS. To improve the performance of IDS, this paper proposes an IDS that its features are optimally selected using a new hybrid method based on fruit fly algorithm (FFA) and ant lion optimizer (ALO) algorithm. The simulation results on the dataset KDD Cup99, NSL-KDD, and UNSW-NB15 have shown that the FFA-ALO has an acceptable performance according to the evaluation criteria such as accuracy and sensitivity than previous approaches.
This study presents a new control system for a linear switched reluctance motor (LSRM). Type-2 Ta... more This study presents a new control system for a linear switched reluctance motor (LSRM). Type-2 Takati-Sugeno fuzzy system is used for the motor approximation. The uncertain parameters of the motor are described by the lower and upper membership functions. By constructing an integral sliding mode surface, an adaptive sliding mode controller is designed and dynamic stability of the sliding motion is verified using the Lyapunov function. The design of the proposed sliding mode surface is independent of the number of fuzzy rules and thus, computational complexity is significantly decreased. The control system is implemented on a double-sided four-phase LSRM and its performance is demonstrated by means of modelling and experimental results.
In this paper, an active damping control scheme for LLCL filters based on the PR (proportional-re... more In this paper, an active damping control scheme for LLCL filters based on the PR (proportional-resonant) regulator is proposed for grid-connected three-level T-type PWM converter systems. The PR controller gives an infinite gain at the resonance frequency. As a result, the oscillation can be suppressed at that frequency. In order to improve the stability of the system in the case of grid impedance variations, online grid impedance estimation is applied. Simulation and experimental results have verified the effectiveness of the proposed scheme for three-phase T-type AC/DC PWM converters.
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