Abstract
This paper presents a mathematical model of a wind turbine and its simulation. This is one of the main resources available to
the island system (Grid-Off system).
Keywords: wind turbine, island system, Grid-Off system, renewable energy source.
1 Introduction to wind turbine
A wind turbine is basically a converter, or in other words a device that transforms one type of energy into
another. In this case, it is the transformation of mechanical energy into electrical energy.
The source of mechanical energy is the flow (flow) of air, which acts on the turbine blades. The blades are
located on a shaft which is coupled to a permanent magnet (magnet). The magnets are a rotating part, which is
named the rotor. The stator consists of a coil (coils) of wound copper conductor. Due to the changing magnetic
field (PM - permanent magnets), an electrical voltage is induced at the terminals (terminals) of the coil / coils. In
essence, it is a synchronous generator, since the variable electric field is coupled (synchronized) with the speed
of the changing and magnetic fields. [1-5]
A schematic block diagram of a wind turbine as a synchronous generator is shown in Fig. 1.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
MATHEMATICAL MODEL OF WIND TURBINE IN GRID-OFF SYSTEM Mellah Hacene
Abstract
This paper deals with the construction of a mathematical model of a wind turbine, which is one of the sources in the Grid-Off
system.
Keywords: mathematical model, wind turbine, Grid-Off system, electric generator, wind conditions.
1 Introduction
As one of the power sources of the Grid-Off system is a wind turbine. It is advantageous to work with a
mathematical model for the need of experimental research. In Fig. 1 is a schematic connection of a wind turbine
to a container, which is a Grid-Off system. [1-4]
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
Dynamic Modeling, Control and Simulation of a Wind and PV Hybrid System for G...IJERA Editor
This paper proposes a dynamic modeling and control strategy for a grid connected hybrid wind and photovoltaic (PV) energy system inter-connected to electrical grid through power electronic interface. A gearless permanent magnet synchronous generator (PMSG) is used to capture the maximum wind energy. The PV and wind systems are connected dc-side of the voltage source inverter through a boost converter individually and maintain a fixed dc output at dc link. A proper control scheme is required to operate power converters to match up the grid connection requirements. This study considered the performance of modeled hybrid system under different case scenarios. All simulation models are developed using MATLAB/Simulink.
In this paper, we focus on the modeling and control of a wind power system based on a Permanent Magnet Synchronous Generator (PMSG). We proposed a technique of control strategies to have the maximum power from wind turbine (WT). This study deals with the problem of Maximum Power Point Tracking (MPPT) based on Takagi Sugeno fuzzy model. The stability analysis is achieved. The gains of the designed controller are calculated by solving Linear Matrix Inequality (LMI). Finally, simulation results are provided to demonstrate the validity and the effectiveness of the proposed method.
Wind energy has many advantages, it does not pollute and it is an inexhaustible source. However, the cost of this energy is still too high to compete with traditional fossil sources. The yield of a wind turbine depends on three parameters: the power of the wind, the turbine power curve and the ability of the generator to respond to fluctuations in the wind. This article presented the MPPT of a wind turbine system equipped with an asynchronous generator has dual power under MatlabSimulink program, in the first time we simulated all the conversion chain with complete model of DFIG and vector control in second stepthen applied the extracted maximum power MPPT strategists, this command is effective and has several advantages it offered to kept the maximum power delivered to network despite all the parameter is change.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...Yayah Zakaria
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind
speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
This paper presents a study analysis of a complete wind energy conversion system, the system based on a doubly fed induction generator (DFIG); a vector control with stator flux orientation of the DFIG is also used to control independently the active and reactive powers. A comparative study have been performed between the conventional PI controller and fuzzy logic control to investigate its dynamic and static performances. This research work involves the study of a phase in advance, to provide effective assistance, to all those who have to make decisions regarding the planning and implementation of wind energy projects. The main objective is to model the wind chain and the use of two types of strategies for the control of this generator to ensure a good regulation we started with the modeling of the wind chain then the modeling of the DFIG and then the use of the two strategies for the regulation of the latter .The complete system is modeled and simulated in the MATLAB/ Simulink. The performance and robustness are analyzed and compared by Matlab / Simulink .Simulation results prove the excellent performance of fuzzy control unit as improving power quality and stability of wind turbine.
MATHEMATICAL MODEL OF WIND TURBINE IN GRID-OFF SYSTEM Mellah Hacene
Abstract
This paper deals with the construction of a mathematical model of a wind turbine, which is one of the sources in the Grid-Off
system.
Keywords: mathematical model, wind turbine, Grid-Off system, electric generator, wind conditions.
1 Introduction
As one of the power sources of the Grid-Off system is a wind turbine. It is advantageous to work with a
mathematical model for the need of experimental research. In Fig. 1 is a schematic connection of a wind turbine
to a container, which is a Grid-Off system. [1-4]
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
Dynamic Modeling, Control and Simulation of a Wind and PV Hybrid System for G...IJERA Editor
This paper proposes a dynamic modeling and control strategy for a grid connected hybrid wind and photovoltaic (PV) energy system inter-connected to electrical grid through power electronic interface. A gearless permanent magnet synchronous generator (PMSG) is used to capture the maximum wind energy. The PV and wind systems are connected dc-side of the voltage source inverter through a boost converter individually and maintain a fixed dc output at dc link. A proper control scheme is required to operate power converters to match up the grid connection requirements. This study considered the performance of modeled hybrid system under different case scenarios. All simulation models are developed using MATLAB/Simulink.
In this paper, we focus on the modeling and control of a wind power system based on a Permanent Magnet Synchronous Generator (PMSG). We proposed a technique of control strategies to have the maximum power from wind turbine (WT). This study deals with the problem of Maximum Power Point Tracking (MPPT) based on Takagi Sugeno fuzzy model. The stability analysis is achieved. The gains of the designed controller are calculated by solving Linear Matrix Inequality (LMI). Finally, simulation results are provided to demonstrate the validity and the effectiveness of the proposed method.
Wind energy has many advantages, it does not pollute and it is an inexhaustible source. However, the cost of this energy is still too high to compete with traditional fossil sources. The yield of a wind turbine depends on three parameters: the power of the wind, the turbine power curve and the ability of the generator to respond to fluctuations in the wind. This article presented the MPPT of a wind turbine system equipped with an asynchronous generator has dual power under MatlabSimulink program, in the first time we simulated all the conversion chain with complete model of DFIG and vector control in second stepthen applied the extracted maximum power MPPT strategists, this command is effective and has several advantages it offered to kept the maximum power delivered to network despite all the parameter is change.
Torque estimator using MPPT method for wind turbines IJECEIAES
In this work, we presents a control scheme of the interface of a grid connected Variable Speed Wind Energy Generation System based on Doubly Fed Induction Generator (DFIG). The vectorial strategy for oriented stator flux GADA has been developed To extract the maximum power MPPT from the wind turbine. It uses a second order sliding mode controller and Kalman observer, using the super twisting algorithm. The simulation describes the effectiveness of the control strategy adopted.For a step and random profiles of the wind speed, reveals better tracking and perfect convergence of electromagnetic torque and concellation of reactive power to the stator. This control limits the mechanical stress on the tansmission shaft, improves the quality of the currents generated on the grid and optimizes the efficiency of the conversion chain.
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
MODELING AND OPTIMIZATION OF PIEZOELECTRIC ENERGY HARVESTING adeij1
In this paper, the modeling, optimization and simulation results of the piezoelectric energy harvesting using bond graph approach are presented. Firstly, a lightweight equivalent model derived from the bond graph is proposed. It’s a comprehensive model, which is suitable for piezoelectric seismic energy harvester investigation and power optimization. The optimal charge impedance for both the resistive load and complex load are given and analysed. Finally a bond graph approach is proposed to allow optimization of the extracted energy while keeping simplicity and standalone capability. The proposed model does not rely on any inductor and is constructed with a simple switch. The power harvested is more than twice the conventional technique one on a wide band of resistive load. The bond graph model is valid close to the analysed mode centre frequency and delivers results compared to experimental and analytical data. Furthermore, we also show that the harvester can be electrically tuned to match the excitation frequency. This makes it possible to maximize the power output for both linear and non-linear loads.
The given paper presents a hybrid electromagnetic suspension designed for high-speed vacuum transport, where the main levitation force is generated by permanent magnets, while the electromagnet controls the air gap. The computer model is designed by means of MATLAB/Simulink software package, which allows us to simulate the dynamic operational modes of the system. The calculated studies are carried out when the vehicle accelerating to 1000 km/h with account of track irregularities. Permanent magnets incorporated in the system of electromagnetic suspension make it possible to reduce the energy consumption needed for levitation force generation.
Wind Turbine Generator Tied To Grid Using Inverter Techniques and Its DesignsIJSRD
This paper proposes a method of using small sizes WTG of 300W low capacity turbine in small grid channel with inverter techniques. Power can be fed directly to grid by improving durability and eliminating battery usage, using WTG inverter technique. The proposed wind tied with grid by PMG includes boost converter and three phase inverter. For tracking wind speed with variations of wind power MPPT method is used. Interleaving technique is adopted for different frequency variables to improve power capacity. Final result proves WTG helps in improving wind power application as shown in simulation result.
The following article presents the control of the power generated by the Doubly Fed Induction Generator, integrated into the wind system, whose rotor is linked to the power converters (Rotor Side Convert (RSC) and Grid Side Converter (GSC)) interfaced by the DC-BUS and connected to the grid via a filter (Rf, Lf) in order to obtain an optimal power to the grid and to ensure system stability. The objective of this study is to understand and to make the comparison between Sliding mode Control technique and the Flux Oriented Control in order to control the Doubly Fed Induction Generator powers exchanged with the grid, it also aims at maintaining the DC-BUS voltage constant and a unit power factor at the grid connection point.The results of simulation show the performance of the Sliding mode Control in terms of monitoring, and robustness with regard to the parametric variations, compared to the Flux Oriented Control. The performance of the systems was tested and compared with the use of MATLAB/Simulink software.
MODELLING, ANALYSIS AND SIMULATION OF THE PIEZOELECTRIC MICRO PUMPadeij1
The piezoelectricity is a reversible phenomenon, which corresponds to the direct piezoelectric effect. So that, the battery loads arrive at the pump, an electronic module must be established in the circuit. A flow pump must be used and its effectiveness must be evaluated according to the desired need. The system is conceived around 24 hour old clock which can be programmed to provide fluid in variable quantity on a regular basis. The piezo-hydraulic pump presented in this work is composed mainly of shareholder piezoelectric with two valves and a diaphragm of the room reinforced by a hard disk. This one is used to improve the performance of the micro-pump in forecast of pump realization. Modeling, analysis and simulation are carried out under SYMBOLS software.
Wind Energy Conversion Based On Matrix ConverterIAES-IJPEDS
In recent years renewable sources such as solar, wave and wind are used for the generation of electricity. Wind is one of the major renewable sources. The amount of energy from a Wind Energy Conversion System (WECS) depends not only on the wind at the site, but also on the control strategy used for the WECS. In assistance to get the appropriate wind energy from the conversion system, wind turbine generator will be run in variable speed mode. The variable speed capability is achieved through the use of an advanced power electronic converter. Fixed speed wind turbines and induction generators are often used in wind farms. But the limitations of such generators are low efficiency and poor power quality which necessitates the variable speed wind turbine generators such as Doubly Fed Induction Generator (DFIG) and Permanent Magnet Synchronous Generator (PMSG). A high-performance configuration can be obtained by using a PMSG and a converter in combination AC-DC-AC connect between stator & rotor points for providing the required variable speed operation.
In this work, we are interested in improving the performance of a doubly-fed induction generator (DFIG)-based wind system, by applying a sliding mode control strategy. The objective is the regulation of the active and reactive power, also the voltage and the frequency of the signal injected into the distribution network. The model proposed for the control is based on the sliding mode technique with performance estimators. The proposed model was validated by a simulation on MATLAB/Simulink.
A Novel Approach Concerning Wind Power EnhancementWaqas Tariq
Being a tropical country, Bangladesh does have wind flow throughout the year. However, the prospect for wind energy in Bangladesh is not at satisfactory level due to low average wind velocities at different regions of the country. The field survey data indicated that the wind velocities are relatively higher from the month of May to August, whereas, it is not so for the rest of the year. Therefore, exploiting the wind energy at low wind velocities is a major predicament in creating a sustainable energy resource for a country with inauspicious forthcoming energy crisis. The scope of this paper concentrates on an innovative approach to harness wind power by installing an auxiliary unit which would only assist the primary turbine unit in case the wind velocity falls under the required value. The auxiliary unit would comprise a secondary turbine, which would be operated by a DC motor connected to a battery system that is charged by a solar panel. A specially designed conduit would encompass both the primary and auxiliary turbine units. A CFD simulation utilizing ANSYS FLOTRAN was carried out to investigate the velocity profiles for different pressure differences at different regions of the prototype conduit. A feasibility analysis of the modified system was eventually carried out for the preferred conduit design.
A solar PV array system is comprised of the following components - solar cells, panel modules, and an array system. Thus, overall optimal design of a solar PV system involves the optimal design of the components at three levels - solar cell, panel module, and array. In the present work, a comparison between different optimization methods is applied to design optimization of single channel Photovoltaic (SCPVT) system. The purpose of these methodologies is to obtain optimum values of the design parameters of SCPVT system, such that the overall economic profit is maximized throughout the PV system lifetime operational period which is not directly calculated in our work rather energy efficiency is calculated . Out of many design parameters available for this system, in the present work only few parameters are taken. The optimal design parameters chosen here are length of channel, depth of channel, velocity of fluid in the cell, and temperature of the cell. The objective function of the proposed optimization algorithm which is Gravitational Search Algorithm (GSA) implemented for design optimization of the system is the energy efficiency, which has to be maximized.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...IJECEIAES
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Torque estimator using MPPT method for wind turbines IJECEIAES
In this work, we presents a control scheme of the interface of a grid connected Variable Speed Wind Energy Generation System based on Doubly Fed Induction Generator (DFIG). The vectorial strategy for oriented stator flux GADA has been developed To extract the maximum power MPPT from the wind turbine. It uses a second order sliding mode controller and Kalman observer, using the super twisting algorithm. The simulation describes the effectiveness of the control strategy adopted.For a step and random profiles of the wind speed, reveals better tracking and perfect convergence of electromagnetic torque and concellation of reactive power to the stator. This control limits the mechanical stress on the tansmission shaft, improves the quality of the currents generated on the grid and optimizes the efficiency of the conversion chain.
Modeling of Wind Energy on Isolated AreaIJPEDS-IAES
In this paper, a model of the wind turbine (WT) with permanent magnet generator (PMSG) and its associated controllers is presented. The increase of wind power penetration in power systems has meant that conventional power plants are gradually being replaced by wind farms. In fact, today wind farms are required to actively participate in power system operation in the same way as conventional power plants. In fact, power system operators have revised the grid connection requirements for wind turbines and wind farms and now demand that these installations be able to carry out more or less the same control tasks as conventional power plants. For dynamic power system simulations, the PMSG wind turbine model includes an aerodynamic rotor model, a lumped mass representation of the drive train system and generator model. In this paper we propose a model with an implementation in MATLAB / Simulink, each of the system components off-grid small wind turbines.
MODELING AND OPTIMIZATION OF PIEZOELECTRIC ENERGY HARVESTING adeij1
In this paper, the modeling, optimization and simulation results of the piezoelectric energy harvesting using bond graph approach are presented. Firstly, a lightweight equivalent model derived from the bond graph is proposed. It’s a comprehensive model, which is suitable for piezoelectric seismic energy harvester investigation and power optimization. The optimal charge impedance for both the resistive load and complex load are given and analysed. Finally a bond graph approach is proposed to allow optimization of the extracted energy while keeping simplicity and standalone capability. The proposed model does not rely on any inductor and is constructed with a simple switch. The power harvested is more than twice the conventional technique one on a wide band of resistive load. The bond graph model is valid close to the analysed mode centre frequency and delivers results compared to experimental and analytical data. Furthermore, we also show that the harvester can be electrically tuned to match the excitation frequency. This makes it possible to maximize the power output for both linear and non-linear loads.
The given paper presents a hybrid electromagnetic suspension designed for high-speed vacuum transport, where the main levitation force is generated by permanent magnets, while the electromagnet controls the air gap. The computer model is designed by means of MATLAB/Simulink software package, which allows us to simulate the dynamic operational modes of the system. The calculated studies are carried out when the vehicle accelerating to 1000 km/h with account of track irregularities. Permanent magnets incorporated in the system of electromagnetic suspension make it possible to reduce the energy consumption needed for levitation force generation.
Wind Turbine Generator Tied To Grid Using Inverter Techniques and Its DesignsIJSRD
This paper proposes a method of using small sizes WTG of 300W low capacity turbine in small grid channel with inverter techniques. Power can be fed directly to grid by improving durability and eliminating battery usage, using WTG inverter technique. The proposed wind tied with grid by PMG includes boost converter and three phase inverter. For tracking wind speed with variations of wind power MPPT method is used. Interleaving technique is adopted for different frequency variables to improve power capacity. Final result proves WTG helps in improving wind power application as shown in simulation result.
The following article presents the control of the power generated by the Doubly Fed Induction Generator, integrated into the wind system, whose rotor is linked to the power converters (Rotor Side Convert (RSC) and Grid Side Converter (GSC)) interfaced by the DC-BUS and connected to the grid via a filter (Rf, Lf) in order to obtain an optimal power to the grid and to ensure system stability. The objective of this study is to understand and to make the comparison between Sliding mode Control technique and the Flux Oriented Control in order to control the Doubly Fed Induction Generator powers exchanged with the grid, it also aims at maintaining the DC-BUS voltage constant and a unit power factor at the grid connection point.The results of simulation show the performance of the Sliding mode Control in terms of monitoring, and robustness with regard to the parametric variations, compared to the Flux Oriented Control. The performance of the systems was tested and compared with the use of MATLAB/Simulink software.
MODELLING, ANALYSIS AND SIMULATION OF THE PIEZOELECTRIC MICRO PUMPadeij1
The piezoelectricity is a reversible phenomenon, which corresponds to the direct piezoelectric effect. So that, the battery loads arrive at the pump, an electronic module must be established in the circuit. A flow pump must be used and its effectiveness must be evaluated according to the desired need. The system is conceived around 24 hour old clock which can be programmed to provide fluid in variable quantity on a regular basis. The piezo-hydraulic pump presented in this work is composed mainly of shareholder piezoelectric with two valves and a diaphragm of the room reinforced by a hard disk. This one is used to improve the performance of the micro-pump in forecast of pump realization. Modeling, analysis and simulation are carried out under SYMBOLS software.
Wind Energy Conversion Based On Matrix ConverterIAES-IJPEDS
In recent years renewable sources such as solar, wave and wind are used for the generation of electricity. Wind is one of the major renewable sources. The amount of energy from a Wind Energy Conversion System (WECS) depends not only on the wind at the site, but also on the control strategy used for the WECS. In assistance to get the appropriate wind energy from the conversion system, wind turbine generator will be run in variable speed mode. The variable speed capability is achieved through the use of an advanced power electronic converter. Fixed speed wind turbines and induction generators are often used in wind farms. But the limitations of such generators are low efficiency and poor power quality which necessitates the variable speed wind turbine generators such as Doubly Fed Induction Generator (DFIG) and Permanent Magnet Synchronous Generator (PMSG). A high-performance configuration can be obtained by using a PMSG and a converter in combination AC-DC-AC connect between stator & rotor points for providing the required variable speed operation.
In this work, we are interested in improving the performance of a doubly-fed induction generator (DFIG)-based wind system, by applying a sliding mode control strategy. The objective is the regulation of the active and reactive power, also the voltage and the frequency of the signal injected into the distribution network. The model proposed for the control is based on the sliding mode technique with performance estimators. The proposed model was validated by a simulation on MATLAB/Simulink.
A Novel Approach Concerning Wind Power EnhancementWaqas Tariq
Being a tropical country, Bangladesh does have wind flow throughout the year. However, the prospect for wind energy in Bangladesh is not at satisfactory level due to low average wind velocities at different regions of the country. The field survey data indicated that the wind velocities are relatively higher from the month of May to August, whereas, it is not so for the rest of the year. Therefore, exploiting the wind energy at low wind velocities is a major predicament in creating a sustainable energy resource for a country with inauspicious forthcoming energy crisis. The scope of this paper concentrates on an innovative approach to harness wind power by installing an auxiliary unit which would only assist the primary turbine unit in case the wind velocity falls under the required value. The auxiliary unit would comprise a secondary turbine, which would be operated by a DC motor connected to a battery system that is charged by a solar panel. A specially designed conduit would encompass both the primary and auxiliary turbine units. A CFD simulation utilizing ANSYS FLOTRAN was carried out to investigate the velocity profiles for different pressure differences at different regions of the prototype conduit. A feasibility analysis of the modified system was eventually carried out for the preferred conduit design.
A solar PV array system is comprised of the following components - solar cells, panel modules, and an array system. Thus, overall optimal design of a solar PV system involves the optimal design of the components at three levels - solar cell, panel module, and array. In the present work, a comparison between different optimization methods is applied to design optimization of single channel Photovoltaic (SCPVT) system. The purpose of these methodologies is to obtain optimum values of the design parameters of SCPVT system, such that the overall economic profit is maximized throughout the PV system lifetime operational period which is not directly calculated in our work rather energy efficiency is calculated . Out of many design parameters available for this system, in the present work only few parameters are taken. The optimal design parameters chosen here are length of channel, depth of channel, velocity of fluid in the cell, and temperature of the cell. The objective function of the proposed optimization algorithm which is Gravitational Search Algorithm (GSA) implemented for design optimization of the system is the energy efficiency, which has to be maximized.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Study of Wind Turbine based Variable Reluctance Generator using Hybrid FEMM-M...IJECEIAES
Based on exhaustive review of the state of the art of the electric generators fitted to Wind Energy Conversion System (WECS), this study is focused on an innovative machine that is a Variable Reluctance Generator (VRG). Indeed, its simple and rugged structure (low cost), its high torque at low speed (gearless), its fault-tolerance (lowest maintenance), allow it to be a potential candidate for a small wind power application at variable wind speed. For better accuracy, a finite element model of a studied doubly salient VRG is developed using open source software FEMM to identify the electromagnetic characteristics such as linkage flux, torque or inductance versus rotor position and stator excitation. The obtained data are then transferred into look-up tables of MATLAB/Simulink to perform various simulations. Performance of the proposed wind power system is analyzed for several parameters and results are discussed.
Performance of a Wind System: Case Study of Sidi Daoud SiteIJERA Editor
This paper describes recent developments of systems for the conversion of wind energy. It presents a modeling and simulation of wind energy conversion system at the site of Sidi Daoud using the experimental results obtained by the services of the company STEG and Madee. We determined the performance of machines based on site properties and dimensional characteristics of the device.
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9 Control Strategies for Variable-speed Fixed-pitch Win.docxevonnehoggarth79783
9
Control Strategies for Variable-speed
Fixed-pitch Wind Turbines
Bunlung Neammanee, Somporn Sirisumrannukul and
Somchai Chatratana1
Department of Electrical Engineering, Faculty of Engineering
King Mongkut’s University of Technology North Bangkok
1National Science and Technology Development Agency
Thailand
1. Introduction
This chapter deals with a design of controllers for variable-speed fixed-pitch wind turbines.
The chapter begins with an introduction to wind turbine control and the detail of nonlinear
models of the wind energy conversion system (WECS). Linearization around a set of
equilibrium points is presented to obtain a linear parameter variable model from a nonlinear
system. Open-loop characteristics for small signals are then described to analyze dynamic
behaviors under different operating conditions. The control objectives for variable-speed
fixed-pitch wind turbines detailed in this chapter consists of three operating conditions:
1. Maximization of extracted energy: The wind turbine should extract wind energy at the
highest efficiency to obtain the highest energy conversion ratio. Three alternative
maximum peak power tracking (MPPT)-based algorithms for fixed pitch wind turbines
are introduced. The first algorithm is guided by a torque reference (Mirecki et at., 2004).
The second method searches an optimal operating point from the slope of the power-
rotational speed curve. The last method is based on the control objective derived from a
fuzzy rule base.
2. Limitation of extracted energy with active stall with rotational speed control: The aim of
this control is to limit stresses on the turbine while minimizing the power fluctuations
around a constant value, normally around the nominal power.
3. Control of MPPT and stall regulation at the overlapping region: This operating
condition is effective with constant rotational speed control.
The controller objectives, controller schemes and controller designs are discussed in detail.
The developed controllers for fixed-pitch wind turbines are based on a speed and torque-
feedback control scheme. The proper design of the reference signal allows accurate tracking
of each control strategy along the entire operating range. Hardware and software
implementation for the control algorithms are explained. The case studies were carried out
with two laboratory experiments with a developed wind turbine simulator: 1) three MPPT
algorithms and active stall regulation with rotational speed control, and 2) an MPPT
algorithm with a grid-connected converter. The chapter is concluded in the last section. The
references are also provided for further research and studies.
Source: Wind Power, Book edited by: S. M. Muyeen,
ISBN 978-953-7619-81-7, pp. 558, June 2010, INTECH, Croatia, downloaded from SCIYO.COM
www.intechopen.com
Wind Power
210
2. Model of variable speed fixed-pitch wind energy conversion system
2.1 Modeling of rotor .
Wind-Driven SEIG Systems: A Comparison StudyCSCJournals
Wind energy is one of the fastest growing renewable energies in the world. This is because it has a much lower environmental impact than conventional energy. In addition, it is one of the lowest-priced renewable energy technologies.
Due to wind speed variation, induction generators are the best choice for such applications. However, they have poor voltage and frequency regulation against wind speed or load variations.
For its operation, the induction generator needs a reasonable amount of reactive power. In stand-alone applications, the reactive power could be supplied to the induction generator by a bank of capacitors as implemented here.
In this paper, simulation of wind turbine driven self excited induction generator (SEIG) has been carried out. Three methods of voltage and frequency regulation have been presented, simulated and analyzed.
The aim of this paper is to compare the three methods from many aspects highlighting the advantages and disadvantages of each one.
This paper focuses on the modeling and control of a wind energy conversion chain using a permanent magnet synchronous machine. This system behaves a turbine, a generator, DC/DC and DC/AC power converters. These are connected on both sides to the DC bus, where the inverter is followed by a filter which is connected to the grid. In this paper, we have been used two types of controllers. For the stator side converter, we consider the Takagi-Sugeno approach where the parameters of controller have been computed by the theory of linear matrix inequalities. The stability synthesis has been checked using the Lyapunov theory. According to the grid side converter, the proportional integral controller is exploited to keep a constant voltage on the DC bus and control both types of powers. The simulation results demonstrate the robustness of the approach used.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Modeling and Control of a Doubly-Fed Induction Generator for Wind Turbine-Gen...IJPEDS-IAES
This paper presents a vector control direct (FOC) of double fed induction generator intended to control the generated stator powers. This device is intended to be implemented in a variable-speed wind-energy conversion system connected to the grid. In order to control the active and reactive power exchanged between the machine stator and the grid, the rotor is fed by a bi-directional converter. The DFIG is controlled by standard relay controllers. Details of the control strategy and system simulation were performed using Simulink and the results are presented in this here to show the effectiveness of the proposed control strategy.
Transient flow analysis for horizontal axial upper-wind turbineinventy
This study is to carry out a transient flow field analysis on the condition that the wind turbine is working to generate turbine, the wind turbine operating conditions change over time, Purpose of this study is try to find out the rule from the wind turbine changing over time . In transient analysis, the wind velocity on inlet boundary and rotation speed in the rotor field will change over time, and an analytical process is provided that can be used for future reference. At present, the wind turbine model is designed on the concept of upwind horizontal axis type. The computer engineering software GH Bladed is used to obtain the relationship between the rotor velocity and the wind turbine. Then the ANSYS engineering software is used to calculate the stress and strain distribution in the blades over time. From the analytical result, the relationship between the stress distribution in the blades and the rotor velocity is got to be used as a reference for future wind turbine structural optimization.
In this paper, we focus on the modeling and control of a wind power system based on a double-fed induction generator DFIG. We proposed a technique of active and reactive power control to improve the performance and dynamics of variable speed wind system. The objective of the modeling is to apply the direct and indirect vector control stator flux orientation to control independently, the active and reactive power generated doubly-fed induction generator (DFIG). The simulation results are tested and compared in order to evaluate the performance of the proposed system.
Power fuzzy adaptive control for wind turbineIJECEIAES
In recent years, wind energy has become one of the most promising renewable energy sources. The doubly-fed induction generator (DFIG) is currently the most common type of generator used in wind farms. This paper describes an approach for the independent control of the active and reactive power of the variable-speed DFIG. This paper deals with the control of the active and reactive powers in a DFIG designed for a wind system. The simulation model including a 7 KW - DFIG driven by a wind turbine, a PWM inverter and the proposed control strategy are developed and implemented using Matlab Simulink.
Optimizing of the installed capacity of hybrid renewable energy with a modifi...IJECEIAES
The lack of wind speed capacity and the emission of photons from sunlight are the problem in a hybrid system of photovoltaic (PV) panels and wind turbines. To overcome this shortcoming, the incremental conductance (IC) algorithm is applied that could control the converter work cycle and the switching of the buck boost therefore maximum efficiency of maximum power point tracking (MPPT) is reached. The operation of the PV-wind hybrid system, consisting of a 100 W PV array device and a 400 W wind subsystem, 12 V/100 Ah battery energy storage and LED, the PV-wind system requires a hybrid controller for battery charging and usage and load lamp and it’s conducted in experimental setup. The experimental has shown that an average increase in power generated was 38.8% compared to a single system of PV panels or a single wind turbine sub-system. Therefore, the potential opportunities for increasing power production in the tropics wheather could be carried out and applied with this model.
This paper presents the modeling and simulation of wind energy Conversion System using the Permanent Magnet Synchronous Generator (PMSG). The objectives are: to extract the maximum power of the wind speed by controlling the electromagnetic torque of the PMSG, to maintain constant the DC-link voltage despite the wind speed variations and to attain the unity power factor. In order to ensure a regulation with high performance and a good robustness against the internal and the external disturbances, a new control strategy called the Active Disturbance Rejection Control (ADRC) is used. Therefore, the Analysis and simulation of the ADRC and PI controllers are developed with MATLAB/Simulink software. The performance of these controllers is compared in term of references tracking, robustness and grid faults.
Commande par gradins d'un convertisseur multiniveau asymétrique à structure c...Mellah Hacene
Commande par gradins d'un convertisseur multiniveau asymétrique à structure cascade pour l'entraînement d'une machine asynchrone
Cet article consiste à étudier la commande des onduleurs multi-niveaux asymétrique appliquée à la conduite d’une machine asynchrone triphasée. On a étudié ce type d’onduleurs parce qu’il est susceptible de générer des tensions quasi sinusoïdale ayant un nombre de niveau impair largement qui peuvent atteindre entre 2K+1 et 3K niveaux (K: cellules à pont complet). L’utilisation de la structure multi-niveaux cascade afin d’améliorer beaucoup plus la qualité de tension de sortie sans augmenter à priori le nombre de cellules d’onduleurs à pont complet ainsi que cette structure est un intérêt certain car elle contient un nombre réduit d’interrupteurs en comparaison avec les autres. Pour l’entraînement à la vitesse variable pour cette machine, la commande vectorielle avec des correcteurs classiques est appliquée ensuite. Les résultats de simulation confirment la validité et l’efficacité de ce type d’onduleur.
Passivity Based Control for PV Applications by Using a Buck Power Converter
The use of power converters for everyday applications is becoming more and more important. Current technological applications simultaneously demand a high level of precision and performance, so DC-DC converters have a very important role in systems requiring energy level conversion and adaptation. As part of the work of this paper, we are interested in an analysis of modeling and control law synthesis approaches to ensure stability and a certain level of performance in the entire operating domain. The objective of our research work is therefore to propose a control law whose synthesis is based on a formalized (modeling & control) approach with a view to obtaining a control law adapted to the operating point. The principles used are based on the control and observation by the theory of passivity for the synthesis of control law of buck power converter for PV Applications.
Cascade forward neural network based on resilient backpropagation for simulta...Mellah Hacene
Cascade-Forward Neural Network Based on Resilient Backpropagation for Simultaneous Parameters and State Space Estimations of Brushed DC Machines
Advances in Modelling and Analysis B
Power transformer faults diagnosis using undestructive methods and ann for dg...Mellah Hacene
Power transformer faults diagnosis using undestructive methods (Roger and IEC) and artificial neural network for dissolved gas analysis applied on the functional transformer in the Algerian north-eastern: a comparative study
Bouchaoui Lahcene, Kamel Eddine Hemsas, Hacene Mellah, saad eddine benlahneche
Nowadays, power transformer aging and failures are viewed with great attention in power transmission industry. Dissolved gas analysis (DGA) is classified among the biggest widely used methods used within the context of asset management policy to detect the incipient faults in their earlier stage in power transformers. Up to now, several procedures have been employed for the lecture of DGA results. Among these useful means, we find Key Gases, Rogers Ratios, IEC Ratios, the historical technique less used today Doernenburg Ratios, the two types of Duval Pentagons methods, several versions of the Duval Triangles method and Logarithmic Nomograph. Problem. DGA data extracted from different units in service served to verify the ability and reliability of these methods in assessing the state of health of the power transformer. Aim. An improving the quality of diagnostics of electrical power transformer by artificial neural network tools based on two conventional methods in the case of a functional power transformer at Sétif province in East North of Algeria. Methodology. Design an inelegant tool for power transformer diagnosis using neural networks based on traditional methods IEC and Rogers, which allows to early detection faults, to increase the reliability, of the entire electrical energy system from transport to consumers and improve a continuity and quality of service. Results. The solution of the problem was carried out by using feed-forward back-propagation neural networks implemented in MATLAB-Simulink environment. Four real power transformers working under different environment and climate conditions such as: desert, humid, cold were taken into account. The practical results of the diagnosis of these power transformers by the DGA are presented. Practical value.....
Adaptive maximum power point tracking using neural networks for a photovoltai...Mellah Hacene
Adaptive Maximum Power Point Tracking Using Neural Networks for a Photovoltaic Systems According Grid
Electrical Engineering & Electromechanics, (5), 57–66, 2021. https://doi.org/10.20998/2074-272X.2021.5.08
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in this paper we interest to how we can validate simultaneously a thermal model and estimated variable of induction motor. This approach is possible by using special simulation package frequently exploited bout in university and industry. A simple description of each one of this famous software is presented.
According to our needs and means; I took a justified choice of the used software in this validation context. In this moment, I make
only the modeling of an induction machine without takes into account the heating effects. Same simulation results of induction
motor model by Maxwell software is given and commented.
4th INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING.,Icee'12 Mellah Hacene
Compared with electrically excited machines, PMSG have a number of economical and technical advantages, so that they are becoming more attractive for direct-drive wind turbines, these advantages can be summarised as follows according to literatures:
Higher efficiency and energy yield,
No additional power supply for the magnet field excitation,
Improvement in the thermal characteristics of the pm machine due to the absence of the field losses,
Higher reliability due to the absence of mechanical components such as slip rings,
Lighter and therefore higher power to weight ratio.
7th International Conference on Electrical Engineering 8- 10 October 2012, Ce...Mellah Hacene
There is now general acceptance that the burning of fossil fuel is having a significant influence on the global climate. Effective mitigation of climate change will require deep reductions in greenhouse gas emissions, with UK estimates of a 60–80% cut being necessary by 2050.
Still purer with the nuclear power, this last leaves behind dangerous wastes for thousands of years and risks contamination of land, air, and water.
Stochastic Estimation Methods for Induction Motor Transient Thermal Monitorin...Mellah Hacene
The induction machine, because of its robustness and low-cost, is commonly
used in the industry. Nevertheless, as every type of electrical machine, this
machine suffers of some limitations. The most important one is the working
temperature which is the dimensioning parameter for the definition of the
nominal working point and the machine lifetime. Due to a strong demand
concerning thermal monitoring methods appeared in the industry sector. In
this context, the adding of temperature sensors is not acceptable and the
studied methods tend to use sensorless approaches such as observators or
parameters estimators like the extended Kalman Filter (EKF). Then the
important criteria are reliability, computational cost ad real time
implementation.
Design and analysis of an external rotor internal-stator doubly fed induction...Mellah Hacene
In this paper, a time stepping 2D and 3D FEM is performed for modeling and analysis external rotor DFIG .The finite element method currently represents the state-of-the-art in the numerical magnetic field computation relating to electrical machines. FEM is a numerical method to solve the partial differential equations (PDE) that expresses the physical quantities of interest, in this case Maxwell’s equations. This will result in a more accurate result compared to analytical modeling, which can be regarded as a simplification of the PDE. FEM analysis is used for transient mode, magnetic field calculation, the magnetic flux density and vector potential of machine is obtained. In this model we including, non linear material characteristics, eddy current effect, torque-speed characteristics, ambient temperature effect and magnetic analysis are investigated using MAXWELL program. With this program, the components of the DFIG can be calculated with high accuracy.
Dynamic design and simulation analysis of permanent magnet motor in different...Mellah Hacene
This paper deals with investigation on non purely sinusoidal input supply analysis of line-start PMM using finite element analysis (FEA), in the present times a greater awareness is generated by the problems of harmonic voltages and currents produced by non-linear loads like the power electronic converters. These combine with non-linear nature of PMM core and produce severe distortions in voltages and currents and increase the power loss, additional copper losses due to harmonic currents, increased core losses, electromagnetic interference with communication circuits, efficiency reduction, increased in motors temperature and torque oscillations. In addition to the operation of PMM on the sinusoidal supplies, the harmonic behavior becomes important as the size and rating of the PMM increases. Thus the study of harmonics is of great practical significance in the operation of PMM.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
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Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
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The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
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Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
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Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
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Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
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During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
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Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
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Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
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Designing Great Products: The Power of Design and Leadership by Chief Designe...
SIMULATION OF A MATHEMATICAL MODEL OF A WIND TURBINE
1. Milan Jus / University Review, Vol. 14, 2020, No. 1, p. 14-18
1
SIMULATION OF A MATHEMATICAL MODEL OF A WIND TURBINE
Milan JUS
Ing. Milan Jus, PhD., Faculty of Special Technology, Alexander Dubček University of Trenčín, Pri Parku 19, 911 06 Trenčín,
Slovakia
Corresponding author E-mail address: milan.jus@tnuni.sk
Abstract
This paper presents a mathematical model of a wind turbine and its simulation. This is one of the main resources available to
the island system (Grid-Off system).
Keywords: wind turbine, island system, Grid-Off system, renewable energy source.
1 Introduction to wind turbine
A wind turbine is basically a converter, or in other words a device that transforms one type of energy into
another. In this case, it is the transformation of mechanical energy into electrical energy.
The source of mechanical energy is the flow (flow) of air, which acts on the turbine blades. The blades are
located on a shaft which is coupled to a permanent magnet (magnet). The magnets are a rotating part, which is
named the rotor. The stator consists of a coil (coils) of wound copper conductor. Due to the changing magnetic
field (PM - permanent magnets), an electrical voltage is induced at the terminals (terminals) of the coil / coils. In
essence, it is a synchronous generator, since the variable electric field is coupled (synchronized) with the speed
of the changing and magnetic fields. [1-5]
A schematic block diagram of a wind turbine as a synchronous generator is shown in Fig. 1.
Fig. 1 Principle block diagram of a wind turbine
The kinetic energy of wind (air) is converted into mechanical energy of a rotating shaft. However, the
validity of the continuity implies that the flow rate slows down on the turbine, since the air flow in front of the
blades is intact with the velocity v and behind the blades the flow velocity is different. This fact is expressed by
the power coefficient of the turbine Cp, which expresses the ratio of the mechanical power of the turbine Pm to
the power of the intact air flow P0, which is expressed by equation (1)
𝐶 𝑝 =
𝑃 𝑚
𝑃0
(1)
The maximum value of the turbine power coefficient is 0.59259, while physically feasible turbines have
smaller values. [5-10]
We calculate the mechanical moment by the ratio of the mechanical power of the turbine to the angular
velocity of the rotor r, which we express mathematically as equation (2)
𝑇 𝑚 =
𝑃 𝑚
𝜔 𝑟
=
𝐶 𝑝
1
2
𝜌𝐴 𝑟 𝑣3
𝜔 𝑟
=
1
2
𝜌𝑣3 𝐶 𝑝 𝐴 𝑟
𝜔 𝑟
(2)
where is the air density and Ar is the rotor area. [11-12]
The mechanical connection of the wind turbine is such that if we proceed chronologically, the blades (blades)
of the wind turbine are connected to the shaft to which the generator rotor is further connected. The blades
Synchronous generatorWIND
2. Milan Jus / University Review, Vol. 14, 2020, No. 1, p. 14-18
2
generate a mechanical moment Tm. The shaft itself has a certain distributed weight, which is expressed by the
moment of inertia, which depends on the time change of the angular velocity of the rotor. In terms of direction,
the torque of the generator Tg (braking torque) acts in the opposite way, the mathematical expression of the
balance of moments is represented by equation (3)
𝑇 𝑚 = 𝐽 𝑎
𝑑𝜔 𝑟
𝑑𝑡
+ 𝑇𝑔 (3)
From the point of view of creating a mathematical model, it is necessary to modify equation (3) into the form
(4)
𝑑𝜔 𝑟
𝑑𝑡
=
1
𝐽 𝑎
(𝑇 𝑚 − 𝑇𝑔) (4)
Next we need to calculate the torque of the generator, which is expressed as (5)
𝑇𝑔 =
3𝐼 𝑔
2 𝐿 𝑠 𝑛 𝑝
2 tan(𝛿)
(5)
where Ig is the current flowing through the generator load, Ls is the stator inductance, np is the number of
generator poles and the angle is between the internal generated voltage Eg and the voltage at the generator
terminals Ug.
The internal voltage of the Eg generator depends on the force of the permanent magnet kPM, the angular
velocity of the rotor r and the number of poles np, which is mathematically expressed as equation (6)
𝐸𝑔 = 𝑘 𝑃𝑀 𝜔𝑟
𝑛 𝑝
2
(6)
If we connect the load Rz to the terminals of the generator, which is schematically shown in Fig. 2, we can
express the equation for the generated voltage Ug at the terminals as equation (7) and the current Ig passing
through the load as equation (8)
𝑈𝑔 = 𝐸𝑔 cos(𝛿) cos(𝜔 𝑔 𝑡) (7)
𝐼𝑔 =
𝑈 𝑔
𝑅 𝑧
=
𝐸 𝑔 cos(𝛿)
𝑅 𝑧
cos(𝜔 𝑔 𝑡) (8)
where g is the angular frequency of the generator current.
Fig. 2 Connecting the load to the generator
2 Mathematical model of wind turbine and its simulation
Based on the mathematical expressions in the previous section, a mathematical model will be constructed,
which essentially consists of four basic blocks as shown in Fig. 3.
Fig. 3 Block diagram of a mathematical model of a wind turbine
Eg Ug Rz
Xd
Ig
v Tm
Tg
Ug, Igr
1 2 3
4
3. Milan Jus / University Review, Vol. 14, 2020, No. 1, p. 14-18
3
The compilation of the model and its simulation was carried out in the SCILAB software, specifically in the
XCos part, where individual blocks 1 to 4 as whole units (sub-blocks) were created and they contained individual
blocks / parts of the scheme that expressed mathematical implementation as required, which is described in the
following text.
Block 1 represents the incorporation of equation (2) into the model, where the inputs are the wind speed and
the value of the angular velocity of the rotor. There are also constants in the model, which are summarized in
Tab. 1. The model of block 1 is shown in Fig. 4.
Fig. 4 Block diagram of block 1 - the output is the mechanical torque Tm
Block 2 after the adjustment expresses equation (4), the adjustment is necessary because the equation
expresses the time change, where the inputs are the mechanical torque (output from block 1) and the generator
torque, which is the output of block 4. The block diagram of block 2 is in Fig. 5.
Fig. 5 Block diagram of block 2 - the output is the angular speed of the rotor r
Block 3 includes equations (6), (7) and (8) and its output is the electrical quantities Ug and Ig. The block
diagram that implements this is shown in Fig. 6.
Fig. 6 Block diagram of block 3 - the output are electrical quantities Ug and Ig
4. Milan Jus / University Review, Vol. 14, 2020, No. 1, p. 14-18
4
Block 4 uses as input only the current flowing through the load Ig and the output is the torque of the
generator, it is basically the realization of equation (5). The block diagram implementing Equation (5) is shown
in Fig. 7.
Fig. 7 Block diagram of block 4 - the output is the torque of the generator Tg
There were also constants in the individual parts of the model that need to be initialized at the beginning of
the simulation. The specific values of the constants used are given in the following Table 1.
Table 1 Stated values of constants used in the wind turbine model
The name of the constant Value Comment
Kpm 10.3668 V.s force PM
np 10 number of generator poles
delta 0.1745329 rad angle between Eg and Ug
cos_delta 0.9848078 cosine angle delta
tan_delta 0.1763270 sine angle delta
Ls 3.07e-3 H stator inductance
Ja 0.748 kg.m2
the resulting moment of inertia
rho 1.29 kg.m-3
air density
Rt 1.35 m rotor radius
Ar 5.7255526 m2
rotor surface
Cp 0.5 power factor
Rz 100 load resistance
The resulting block diagram represents the circuit according to Fig. 3, where the individual blocks are
interconnected and also blocks for displaying waveforms are added. Such a complete connection of the wind
turbine model is shown in Fig. 8.
Fig. 8 Final simulation model of a wind turbine
In the given model shown in Fig. 8, a simulation was performed where the input to the model was a variable
wind speed to which the wind turbine is exposed. The end load was a resistance with a value of 100 and only
the course of the generated current Ig passing through the load Rz was evaluated.
5. Milan Jus / University Review, Vol. 14, 2020, No. 1, p. 14-18
5
In Fig. 9 shows the simulated course of the generated current at the same time as the course expressing the
change in wind speed (shown in blue), where it is possible to see the reaction to the change in current (shown in
green) size from the change in wind speed. The value of wind speed is in m.s-1
and the value of current
magnitude in A, since these values are close in size, therefore one scale on the y-axis is used.
Fig. 9 The simulated course of the generated Ig current
3 Conclusion
In this paper, a mathematical model designed to simulate a wind turbine was designed and built. The current
generated through the load was mainly simulated and presented. The input to the simulation was the variable
magnitude of the wind speed acting on the wind turbine. The simulation shows that if we take Igmax = 2.7 A and a
load of 100 , the maximum power was 730 W.
Acknowledgements
The paper was treated within the project no. ITMS 26220220083 "Research technological base for designing
applications for renewable energy in practice" EU operational program "Research and Development".
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