This document discusses direct drive wind turbines. It begins with an introduction explaining the motivation for wind energy and classifications of wind turbines. It then provides details on the configuration, working principle, and modeling of direct drive wind turbines. The main types discussed are direct drive wind turbines with a wound rotor synchronous generator and permanent magnet synchronous generator. Their operation, advantages like reduced mechanical stress and ability to control reactive power, and limitations such as additional power electronics needs are summarized. Comparisons are made between variable and fixed speed operation as well as different generator types.
An Axial-Flux Permanent Magnet (AFPM) Generator for Defence Applications - Pa...IDES Editor
The document discusses the development of a novel axial-flux permanent magnet (AFPM) generator for defense applications. AFPM generators have advantages over conventional machines as they are compact, lightweight, and highly efficient. The authors developed a prototype 40kVA AFPM generator with twin stators and a sandwiched rotor. Testing showed the generator performed well under resistive and inductive loads, with 94% efficiency and smooth sinusoidal voltage output. Due to its unique features, the AFPM generator is well-suited as a futuristic power source for defense equipment.
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a wind power generation system using a permanent magnet synchronous...eSAT Journals
Abstract This paper presents a wind power system using a Permanent Magnet Synchronous Machine (PMSM). The whole system consists of a wind turbine, a permanent magnet synchronous machine, a three phase diode rectifier, a boost converter, a transformer-less step down circuit, an H-bridge inverter and a T-LCL filter. The 3-phase AC output from the PMSM is sent to the 3-phase diode rectifier for conversion to DC and a boost regulator is used to step-up this DC voltage to the desired level. This step-upped DC voltage is then converted into AC output by the H-Bridge inverter. The switching technique of the proposed inverter consists of a combination of Sinusoidal Pulse Width Modulation (SPWM) and a square wave along with grid synchronization conditions. As the suggested method is entirely transformer-less, it significantly reduces Total Harmonic Distortion (THD) to less than 0.1% and minimizes its size. The T-LCL Immittance Converter not only reduces the harmonics of the inverter output but also provides a nearly constant output current thereby stabilizing the system. The system setup and the simulation results were obtained using the PSIM software. Keywords: Wind Turbine, Permanent Magnet Synchronous Machine, Boost Converter, Step- down Circuit, T-LCL Immittance Converter, Inverter
A new design method for low speed torus type afpm machine for hev applicationseSAT Journals
Abstract Axial flux permanent magnet (AFPM) machine type has some advantages such as compressed packaging, easy handling, and safety operation. In this paper the proper structure selection of AFPM machine for hybrid electric vehicle (HEV) application is one of the aims. To reduce the losses and the total volume of machine, the coreless TORUS-NS type machine is selected. Designing of this machine, to obtain a wide speed range with high efficiency, low cogging torque and high torque value, as in-wheel direct-drive AFPM machine for HEV, is investigated. The operation performance in low and medium speed ranges is studied. A new design method based on multi speed design (MSD) strategy is proposed. Using this method with a coreless type of stators, the total AFPM machine efficiency at the HEV operation cycles could be improved. Performance analysis of this in-wheel AFPM machine is done using finite-element method (FEM). FEM analysis of the single-speed design (SSD) method is also done. MSD and SSD designed machines are applied in HEV and simulated using urban and highway cycles. The obtained results show the better performance of HEV, using the MSD based designed machine in all operation cycles. The experimental results obtained from sample practical prototype, confirm the analytical method. Keywords: Hybrid electric vehicles (HEV), axial flux permanent magnet (AFPM), TORUS type, direct-drive, in-wheel, multi-speed design, single-speed design.
Analysis of PMSG in Wind Integration using T Source Inverter with Simple Boos...IJTET Journal
The Analysis of PMSG in wind integration using a T-source Inverter with the Simple Boost Control technique for
improving voltage gain is proposed. The Permanent Magnet Synchronous Generator (PMSG) offers higher performance than other
generators because of its higher efficiency with less maintenance. Since they don’t have rotor current, can be used without a gearbox,
which also implies a reduction of the weight of the nacelle with a reduction of costs. T-Source Inverter has high frequency, low
leakage inductance transformer and one capacitance this is the main difference from the Z-source Inverter. It has low active
components in compare with conventional ZSI. The T source network has an ability to perform DC to AC power conversion. It
provides buck boost operation in a single stage, but the traditional Inverter cannot provide such feature. All the components of the
wind turbine and the grid-side converter are developed and implemented in MATLAB/Simulink.
The permanent magnet synchronous generator uses permanent magnets on the rotor instead of an external excitation source. It has a simpler design without slip rings or brushes. These generators are commonly used with wind turbines, gas turbines, and hydro turbines. They have higher efficiency than generators with electromagnetic excitation due to not having excitation losses. However, large high power permanent magnet synchronous generators can be more expensive than other types.
This document discusses wind turbine generator technologies. It describes the typical components of a wind turbine, including the gearbox and different methods for mechanical speed regulation. It then summarizes the four main types of wind turbine generator technologies presently used: squirrel cage induction generators, induction generators with variable external rotor resistance, doubly fed induction generators, and synchronous or induction generators with full converter interfaces. It provides details on doubly fed induction generators, including their control and protection systems. The document discusses the impact of large wind power plants on power system dynamics and stability.
An Axial-Flux Permanent Magnet (AFPM) Generator for Defence Applications - Pa...IDES Editor
The document discusses the development of a novel axial-flux permanent magnet (AFPM) generator for defense applications. AFPM generators have advantages over conventional machines as they are compact, lightweight, and highly efficient. The authors developed a prototype 40kVA AFPM generator with twin stators and a sandwiched rotor. Testing showed the generator performed well under resistive and inductive loads, with 94% efficiency and smooth sinusoidal voltage output. Due to its unique features, the AFPM generator is well-suited as a futuristic power source for defense equipment.
IOSR Journal of Electrical and Electronics Engineering(IOSR-JEEE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of electrical and electronics engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in electrical and electronics engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a wind power generation system using a permanent magnet synchronous...eSAT Journals
Abstract This paper presents a wind power system using a Permanent Magnet Synchronous Machine (PMSM). The whole system consists of a wind turbine, a permanent magnet synchronous machine, a three phase diode rectifier, a boost converter, a transformer-less step down circuit, an H-bridge inverter and a T-LCL filter. The 3-phase AC output from the PMSM is sent to the 3-phase diode rectifier for conversion to DC and a boost regulator is used to step-up this DC voltage to the desired level. This step-upped DC voltage is then converted into AC output by the H-Bridge inverter. The switching technique of the proposed inverter consists of a combination of Sinusoidal Pulse Width Modulation (SPWM) and a square wave along with grid synchronization conditions. As the suggested method is entirely transformer-less, it significantly reduces Total Harmonic Distortion (THD) to less than 0.1% and minimizes its size. The T-LCL Immittance Converter not only reduces the harmonics of the inverter output but also provides a nearly constant output current thereby stabilizing the system. The system setup and the simulation results were obtained using the PSIM software. Keywords: Wind Turbine, Permanent Magnet Synchronous Machine, Boost Converter, Step- down Circuit, T-LCL Immittance Converter, Inverter
A new design method for low speed torus type afpm machine for hev applicationseSAT Journals
Abstract Axial flux permanent magnet (AFPM) machine type has some advantages such as compressed packaging, easy handling, and safety operation. In this paper the proper structure selection of AFPM machine for hybrid electric vehicle (HEV) application is one of the aims. To reduce the losses and the total volume of machine, the coreless TORUS-NS type machine is selected. Designing of this machine, to obtain a wide speed range with high efficiency, low cogging torque and high torque value, as in-wheel direct-drive AFPM machine for HEV, is investigated. The operation performance in low and medium speed ranges is studied. A new design method based on multi speed design (MSD) strategy is proposed. Using this method with a coreless type of stators, the total AFPM machine efficiency at the HEV operation cycles could be improved. Performance analysis of this in-wheel AFPM machine is done using finite-element method (FEM). FEM analysis of the single-speed design (SSD) method is also done. MSD and SSD designed machines are applied in HEV and simulated using urban and highway cycles. The obtained results show the better performance of HEV, using the MSD based designed machine in all operation cycles. The experimental results obtained from sample practical prototype, confirm the analytical method. Keywords: Hybrid electric vehicles (HEV), axial flux permanent magnet (AFPM), TORUS type, direct-drive, in-wheel, multi-speed design, single-speed design.
Analysis of PMSG in Wind Integration using T Source Inverter with Simple Boos...IJTET Journal
The Analysis of PMSG in wind integration using a T-source Inverter with the Simple Boost Control technique for
improving voltage gain is proposed. The Permanent Magnet Synchronous Generator (PMSG) offers higher performance than other
generators because of its higher efficiency with less maintenance. Since they don’t have rotor current, can be used without a gearbox,
which also implies a reduction of the weight of the nacelle with a reduction of costs. T-Source Inverter has high frequency, low
leakage inductance transformer and one capacitance this is the main difference from the Z-source Inverter. It has low active
components in compare with conventional ZSI. The T source network has an ability to perform DC to AC power conversion. It
provides buck boost operation in a single stage, but the traditional Inverter cannot provide such feature. All the components of the
wind turbine and the grid-side converter are developed and implemented in MATLAB/Simulink.
The permanent magnet synchronous generator uses permanent magnets on the rotor instead of an external excitation source. It has a simpler design without slip rings or brushes. These generators are commonly used with wind turbines, gas turbines, and hydro turbines. They have higher efficiency than generators with electromagnetic excitation due to not having excitation losses. However, large high power permanent magnet synchronous generators can be more expensive than other types.
This document discusses wind turbine generator technologies. It describes the typical components of a wind turbine, including the gearbox and different methods for mechanical speed regulation. It then summarizes the four main types of wind turbine generator technologies presently used: squirrel cage induction generators, induction generators with variable external rotor resistance, doubly fed induction generators, and synchronous or induction generators with full converter interfaces. It provides details on doubly fed induction generators, including their control and protection systems. The document discusses the impact of large wind power plants on power system dynamics and stability.
This document discusses different types of electric motors:
1. Permanent magnet synchronous motors have constant torque output but are expensive and available only in small sizes. They are used in precision equipment.
2. Stepped motors move in discrete steps and have multiple coil phases. Variable-reluctance stepped motors work by aligning the rotor with the stator's magnetic field. Permanent magnet stepped motors produce more torque but require reversing current to change direction.
3. Brushless DC motors have electronically controlled commutation without brushes, making them more efficient than brushed DC motors. They are used in computer hard drives and other applications.
A PFC Fed Asynchronous Generator For Advanced Wind Power Generation Excited B...IOSR Journals
This document describes a proposed system for wind power generation using an asynchronous generator excited by a voltage source inverter. The system aims to reduce costs compared to using an expensive synchronous generator. It consists of a power factor correction converter (PFCC) combining a diode rectifier and boost chopper, and a voltage source converter (VSC). In the system, the VSC supplies reactive power to excite the induction generator, while the PFCC controls the duty cycle to regulate real power from the generator. Simulation results in MATLAB/Simulink show that this configuration can efficiently generate power from the induction generator at variable speeds below synchronous speed by controlling the VSC and PFCC.
This document summarizes a research paper that models and simulates the behavior of a Doubly Fed Induction Generator (DFIG) during faulty grid conditions using Matlab. It describes how a three-phase fault is created using a fault block, and the converter connected to the rotor is disconnected and the rotor is shorted by dump resistances after the fault occurs. The paper presents the normal and faulty operating equivalent circuits of the DFIG. It also describes the Matlab simulation model developed, including blocks for the DFIG and dump resistor protection. Simulation results are shown graphically comparing stator current with time during a 0.2 to 0.3 second fault period.
IRJET- Design and Implementation of Transformerless Mosfet Inverter for a Gri...IRJET Journal
This document proposes a design for a transformerless MOSFET inverter for a single-phase grid-connected photovoltaic system. The proposed topology uses superjunction MOSFETs and silicon carbide diodes to improve efficiency. It combines aspects of existing HERIC and H5 inverter topologies by using asymmetric legs with MOSFETs and diodes instead of IGBTs. This avoids problems with reverse recovery and dead time that exist in other designs. A clamping branch is added to clamp the common mode voltage during the freewheeling period, further improving efficiency. The design is intended to provide high efficiency output with low distortion for connecting solar panels to the electric grid.
Alternator wikipedia, the free encyclopediabijander kumar
This document provides an overview of alternators from Wikipedia. It discusses that an alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. It operates by using a rotating magnetic field to induce an electric current in stationary conductors. Alternators are commonly used in automobiles, power plants and other applications to generate electrical power. They produce alternating current at a frequency that depends on the number of poles and rotational speed of the device.
Full-scale converter for synchronous wind turbine generatorsLong Thang Pham
This document summarizes a presentation about full scale converters for synchronous wind turbine generators. It begins with an introduction to the evolution of wind turbines over time towards larger capacity and increased use of power electronics. It then covers the characteristics of variable speed wind turbines using full scale converters, including advantages like high efficiency and reactive power control. The document reviews different generator and converter designs that have been used in wind turbines. It also discusses control strategies for both the generator side and grid side converters. Applications of variable speed wind turbines using full scale converters are described for both onshore and offshore wind power. The conclusion discusses future directions such as developing offshore wind farms and improving efficiency and reliability.
Class-13 These slides majorly focus on wind turbine components and wind turbine characteristics. Later based on this basic idea, we will discuss about the various control strategies for wind generators.
This document discusses improving the reactive power capability of doubly fed induction generators (DFIGs) used in wind turbines. It provides background on DFIGs and how they work in wind turbines to generate electricity through a gearbox and generator connected to the grid via power electronics. The document aims to analyze how adjusting the ratings of grid-side converters can enhance the reactive power capability curves of DFIGs for different stator voltages. It also examines DFIG performance during voltage dips and the use of crowbar protection circuits to model active crowbar behavior.
Speed torque characteristics of brushless dc motor in either direction on loa...Alexander Decker
1. The document discusses the speed-torque characteristics of a brushless DC motor when operating in both forward and reverse directions under load using an ARM controller.
2. A three-phase bridge inverter with MOSFET switches is used to convert DC power to the three-phase AC needed to drive the brushless DC motor. Hall sensors provide position feedback to the ARM controller to control the switching of the inverter.
3. Experiments were conducted where a dynamometer was used to apply variable loads to the motor. Speed-torque characteristics were measured for operation in both directions.
Commanding Doubly-Fed Induction Generator (DFIG) to Decouple Active and React...IOSR Journals
This document analyzes the steady-state characteristics of a wind energy conversion system (WECS) using a doubly fed induction generator (DFIG) through MATLAB simulation. The simulation examines various DFIG operating characteristics including torque-speed curves and how active and reactive power outputs are affected by changes in the rotor voltage. Key findings are that adjusting the rotor voltage can shift the DFIG's operating range and expand its torque/power capabilities, and can also influence whether the generator absorbs or produces reactive power from the grid.
PROJECT REPORT anti theft and auto braking carMehul kumar
The induction braking coil works by shorting the circuit around the stepper motor pins when activated by a relay, which stops the shaft of the vehicle momentarily. The IR sensing circuit uses a 555 timer and relay switching to sense obstructions, activating one relay to stop the DC motor and another to energize the induction braking coil, providing two mechanisms to brake the hybrid vehicle model. The induction braking coil provides an additional braking mechanism to the vehicle by shorting the stepper motor when a relay is triggered by the IR sensing circuit.
This document discusses the study and manufacturing of an alternator. It begins by introducing the importance of electricity in economic development and the need to increase power generation capacity. It then describes the main components of a turbo generator including the rotor, stator, and exciter. The principles of electromagnetic induction and operation of generators are explained. Details are provided on the construction of the stator core and winding, as well as insulation systems and vacuum pressure impregnation. Finally, the document briefly discusses the different types of exciters used.
Wind Energy Conversion System Using PMSG with T-Source Three Phase Matrix Con...IJTET Journal
This document presents a wind energy conversion system using a permanent magnet synchronous generator (PMSG) connected to a T-source three-phase matrix converter. The system aims to efficiently harness wind power and deliver it to a load. A PMSG is connected to a three-phase diode rectifier and input capacitors, with the output fed to a T-source network and three-phase matrix converter. The converter can boost output voltage regardless of input voltage and regulate it through shoot-through control. MATLAB/Simulink models are developed and simulations show the converter produces controlled output voltage and current waveforms to power the load efficiently with fewer components than traditional converter topologies.
Iaetsd a new multilevel inverter topology for fourIaetsd Iaetsd
This document proposes a new multilevel inverter topology for driving a four-pole induction motor. The topology uses four two-level inverters connected to the separated windings of the motor's stator to generate five voltage levels. This is done using a single DC link shared between the inverters. Sine triangular pulse width modulation is used to generate switching signals while avoiding common mode currents. Simulation results show the output voltage waveform for different modulation indices as well as the speed-torque characteristics of the induction motor driven by the proposed inverter topology. The topology reduces harmonics and improves efficiency compared to traditional multilevel inverter configurations.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
Ponencia de Alexandros Konstantinidis (SEYNers) durante su participación en el workShop de la Semana de la Energía Limpia de Canarias (4 y 10 de abril de 2016) organizado por ei ICEACAN - Instituto de las Comunidades Energéticas Autosuficlentes de Canarias - islas Cananas - España
Development of high temperature magnetic bearingsjinfangliu
The document discusses a NASA/Electron Energy Corporation (EEC) Small Business Innovation Research (SBIR) project to develop high temperature permanent magnet biased magnetic bearings and motors. The project aims to utilize EEC's patented SmCo magnets that can operate up to 550°C to develop a technology demonstrator operating at 540°C, including a motor and radial/thrust magnetic bearings. Bench tests of a designed radial bearing show it can produce over 2800N of force at 500°C, around 86% of room temperature performance. A solid model and test apparatus are presented, demonstrating progress toward the project goals.
This paper is an attempt to develop an Induction Motor Drive System with Multilevel Inverter topology for reduced torque ripple application. A Nine level-cascaded multilevel inverter is developed for the induction motor drive with SVPWM control powered by boost converter fed using solar PV supply. The SVPWM control based implementation of vector control using a multilevel inverter topology needs a multilevel SVPWM control technique, which is implemented in this paper. The Solar power supplied is applied with the MPPT technique and the supplied DC power is fed to the three phase cascaded 9 level multilevel inverter. The vector control of induction motor is carried out using the SVPWM technique on the multilevel topology. The torque ripple reduction in the output is observed and compared with the vector control of induction motor. Matlab based implementation is carried out and the results are tabulated and inferred.
In recent years, Permanent Magnet Synchronous Machines (PMSMs) are increasing
applied in several areas such as generation, traction, automobiles, robotics and aerospace
technology. Basically PMSG topology has been beneficial for slow speed and variable speed
operation and steady state output power produced in operation. PMSG is a part of
synchronous machine family, so its construction features almost equivalent to synchronous
machine.
With respect of designing a PMSG, the permanent magnetic pole lies on the rotor and
armature winding are in the inner part of stator that is electrically connected to the load.
Armature winding consists of the set of three conductors which has phase difference 1200
apart to each other and providing a uniform force or torque on the generator’s rotor. To
operate PMGS, it is connected to wind turbine through a shaft without gear box and rotate at
slow speed. This uniform torque produced by the resultant magnetic flux which induces
current in the armature winding. The stator magnetic field combined spatially with rotor
magnetic flux and rotates as the same speed of the rotor. So the two magnetic fields
synchronously rotate in PGSM to maintain the relative motion of rotor and stator.
Thus the permanent magnets rotates at constant speed without any DC excitation system,
which means it has not required any slip rings and contact brushes to make it more reliability
or efficient.
IRJET- Application of Small Wind Turbine in Small Grid using Permanent Magnet...IRJET Journal
This document discusses the use of permanent magnet synchronous generators (PMSG) for small wind turbines connected to small grids. It first provides background on PMSGs and their advantages over other generator types for wind applications. It then describes the methodology of using a PMSG connected to a voltage source converter and low pass filter to integrate the output of a small wind turbine into a small grid. The document concludes that using small electrical machines modified as PMSGs can provide a low-cost alternative for generating power from small wind turbines and connecting it to small grids or microgrids.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses different types of electric motors:
1. Permanent magnet synchronous motors have constant torque output but are expensive and available only in small sizes. They are used in precision equipment.
2. Stepped motors move in discrete steps and have multiple coil phases. Variable-reluctance stepped motors work by aligning the rotor with the stator's magnetic field. Permanent magnet stepped motors produce more torque but require reversing current to change direction.
3. Brushless DC motors have electronically controlled commutation without brushes, making them more efficient than brushed DC motors. They are used in computer hard drives and other applications.
A PFC Fed Asynchronous Generator For Advanced Wind Power Generation Excited B...IOSR Journals
This document describes a proposed system for wind power generation using an asynchronous generator excited by a voltage source inverter. The system aims to reduce costs compared to using an expensive synchronous generator. It consists of a power factor correction converter (PFCC) combining a diode rectifier and boost chopper, and a voltage source converter (VSC). In the system, the VSC supplies reactive power to excite the induction generator, while the PFCC controls the duty cycle to regulate real power from the generator. Simulation results in MATLAB/Simulink show that this configuration can efficiently generate power from the induction generator at variable speeds below synchronous speed by controlling the VSC and PFCC.
This document summarizes a research paper that models and simulates the behavior of a Doubly Fed Induction Generator (DFIG) during faulty grid conditions using Matlab. It describes how a three-phase fault is created using a fault block, and the converter connected to the rotor is disconnected and the rotor is shorted by dump resistances after the fault occurs. The paper presents the normal and faulty operating equivalent circuits of the DFIG. It also describes the Matlab simulation model developed, including blocks for the DFIG and dump resistor protection. Simulation results are shown graphically comparing stator current with time during a 0.2 to 0.3 second fault period.
IRJET- Design and Implementation of Transformerless Mosfet Inverter for a Gri...IRJET Journal
This document proposes a design for a transformerless MOSFET inverter for a single-phase grid-connected photovoltaic system. The proposed topology uses superjunction MOSFETs and silicon carbide diodes to improve efficiency. It combines aspects of existing HERIC and H5 inverter topologies by using asymmetric legs with MOSFETs and diodes instead of IGBTs. This avoids problems with reverse recovery and dead time that exist in other designs. A clamping branch is added to clamp the common mode voltage during the freewheeling period, further improving efficiency. The design is intended to provide high efficiency output with low distortion for connecting solar panels to the electric grid.
Alternator wikipedia, the free encyclopediabijander kumar
This document provides an overview of alternators from Wikipedia. It discusses that an alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. It operates by using a rotating magnetic field to induce an electric current in stationary conductors. Alternators are commonly used in automobiles, power plants and other applications to generate electrical power. They produce alternating current at a frequency that depends on the number of poles and rotational speed of the device.
Full-scale converter for synchronous wind turbine generatorsLong Thang Pham
This document summarizes a presentation about full scale converters for synchronous wind turbine generators. It begins with an introduction to the evolution of wind turbines over time towards larger capacity and increased use of power electronics. It then covers the characteristics of variable speed wind turbines using full scale converters, including advantages like high efficiency and reactive power control. The document reviews different generator and converter designs that have been used in wind turbines. It also discusses control strategies for both the generator side and grid side converters. Applications of variable speed wind turbines using full scale converters are described for both onshore and offshore wind power. The conclusion discusses future directions such as developing offshore wind farms and improving efficiency and reliability.
Class-13 These slides majorly focus on wind turbine components and wind turbine characteristics. Later based on this basic idea, we will discuss about the various control strategies for wind generators.
This document discusses improving the reactive power capability of doubly fed induction generators (DFIGs) used in wind turbines. It provides background on DFIGs and how they work in wind turbines to generate electricity through a gearbox and generator connected to the grid via power electronics. The document aims to analyze how adjusting the ratings of grid-side converters can enhance the reactive power capability curves of DFIGs for different stator voltages. It also examines DFIG performance during voltage dips and the use of crowbar protection circuits to model active crowbar behavior.
Speed torque characteristics of brushless dc motor in either direction on loa...Alexander Decker
1. The document discusses the speed-torque characteristics of a brushless DC motor when operating in both forward and reverse directions under load using an ARM controller.
2. A three-phase bridge inverter with MOSFET switches is used to convert DC power to the three-phase AC needed to drive the brushless DC motor. Hall sensors provide position feedback to the ARM controller to control the switching of the inverter.
3. Experiments were conducted where a dynamometer was used to apply variable loads to the motor. Speed-torque characteristics were measured for operation in both directions.
Commanding Doubly-Fed Induction Generator (DFIG) to Decouple Active and React...IOSR Journals
This document analyzes the steady-state characteristics of a wind energy conversion system (WECS) using a doubly fed induction generator (DFIG) through MATLAB simulation. The simulation examines various DFIG operating characteristics including torque-speed curves and how active and reactive power outputs are affected by changes in the rotor voltage. Key findings are that adjusting the rotor voltage can shift the DFIG's operating range and expand its torque/power capabilities, and can also influence whether the generator absorbs or produces reactive power from the grid.
PROJECT REPORT anti theft and auto braking carMehul kumar
The induction braking coil works by shorting the circuit around the stepper motor pins when activated by a relay, which stops the shaft of the vehicle momentarily. The IR sensing circuit uses a 555 timer and relay switching to sense obstructions, activating one relay to stop the DC motor and another to energize the induction braking coil, providing two mechanisms to brake the hybrid vehicle model. The induction braking coil provides an additional braking mechanism to the vehicle by shorting the stepper motor when a relay is triggered by the IR sensing circuit.
This document discusses the study and manufacturing of an alternator. It begins by introducing the importance of electricity in economic development and the need to increase power generation capacity. It then describes the main components of a turbo generator including the rotor, stator, and exciter. The principles of electromagnetic induction and operation of generators are explained. Details are provided on the construction of the stator core and winding, as well as insulation systems and vacuum pressure impregnation. Finally, the document briefly discusses the different types of exciters used.
Wind Energy Conversion System Using PMSG with T-Source Three Phase Matrix Con...IJTET Journal
This document presents a wind energy conversion system using a permanent magnet synchronous generator (PMSG) connected to a T-source three-phase matrix converter. The system aims to efficiently harness wind power and deliver it to a load. A PMSG is connected to a three-phase diode rectifier and input capacitors, with the output fed to a T-source network and three-phase matrix converter. The converter can boost output voltage regardless of input voltage and regulate it through shoot-through control. MATLAB/Simulink models are developed and simulations show the converter produces controlled output voltage and current waveforms to power the load efficiently with fewer components than traditional converter topologies.
Iaetsd a new multilevel inverter topology for fourIaetsd Iaetsd
This document proposes a new multilevel inverter topology for driving a four-pole induction motor. The topology uses four two-level inverters connected to the separated windings of the motor's stator to generate five voltage levels. This is done using a single DC link shared between the inverters. Sine triangular pulse width modulation is used to generate switching signals while avoiding common mode currents. Simulation results show the output voltage waveform for different modulation indices as well as the speed-torque characteristics of the induction motor driven by the proposed inverter topology. The topology reduces harmonics and improves efficiency compared to traditional multilevel inverter configurations.
Design and Development of Passive Magnetic BearingIJMER
Passive Magnetic Bearings (PMB) are known for their non-contact and negligible friction
operations but these desirable characteristics of PMB can only be attained if proper designing of bearing
is carried out based on the applied load. To aid to the design of PMB, 3D Coulombian model to estimate
the load carrying capacity of magnetic bearings has been proposed. To exemplify the design procedure,
analyses of various configurations of magnetic bearings have been presented. To economize the magnetic
bearings, usage of easily available square magnets in stator made of aluminium has been proposed.
Finally, a case study has been included to illustrate the design of magnetic bearing.
Ponencia de Alexandros Konstantinidis (SEYNers) durante su participación en el workShop de la Semana de la Energía Limpia de Canarias (4 y 10 de abril de 2016) organizado por ei ICEACAN - Instituto de las Comunidades Energéticas Autosuficlentes de Canarias - islas Cananas - España
Development of high temperature magnetic bearingsjinfangliu
The document discusses a NASA/Electron Energy Corporation (EEC) Small Business Innovation Research (SBIR) project to develop high temperature permanent magnet biased magnetic bearings and motors. The project aims to utilize EEC's patented SmCo magnets that can operate up to 550°C to develop a technology demonstrator operating at 540°C, including a motor and radial/thrust magnetic bearings. Bench tests of a designed radial bearing show it can produce over 2800N of force at 500°C, around 86% of room temperature performance. A solid model and test apparatus are presented, demonstrating progress toward the project goals.
This paper is an attempt to develop an Induction Motor Drive System with Multilevel Inverter topology for reduced torque ripple application. A Nine level-cascaded multilevel inverter is developed for the induction motor drive with SVPWM control powered by boost converter fed using solar PV supply. The SVPWM control based implementation of vector control using a multilevel inverter topology needs a multilevel SVPWM control technique, which is implemented in this paper. The Solar power supplied is applied with the MPPT technique and the supplied DC power is fed to the three phase cascaded 9 level multilevel inverter. The vector control of induction motor is carried out using the SVPWM technique on the multilevel topology. The torque ripple reduction in the output is observed and compared with the vector control of induction motor. Matlab based implementation is carried out and the results are tabulated and inferred.
In recent years, Permanent Magnet Synchronous Machines (PMSMs) are increasing
applied in several areas such as generation, traction, automobiles, robotics and aerospace
technology. Basically PMSG topology has been beneficial for slow speed and variable speed
operation and steady state output power produced in operation. PMSG is a part of
synchronous machine family, so its construction features almost equivalent to synchronous
machine.
With respect of designing a PMSG, the permanent magnetic pole lies on the rotor and
armature winding are in the inner part of stator that is electrically connected to the load.
Armature winding consists of the set of three conductors which has phase difference 1200
apart to each other and providing a uniform force or torque on the generator’s rotor. To
operate PMGS, it is connected to wind turbine through a shaft without gear box and rotate at
slow speed. This uniform torque produced by the resultant magnetic flux which induces
current in the armature winding. The stator magnetic field combined spatially with rotor
magnetic flux and rotates as the same speed of the rotor. So the two magnetic fields
synchronously rotate in PGSM to maintain the relative motion of rotor and stator.
Thus the permanent magnets rotates at constant speed without any DC excitation system,
which means it has not required any slip rings and contact brushes to make it more reliability
or efficient.
IRJET- Application of Small Wind Turbine in Small Grid using Permanent Magnet...IRJET Journal
This document discusses the use of permanent magnet synchronous generators (PMSG) for small wind turbines connected to small grids. It first provides background on PMSGs and their advantages over other generator types for wind applications. It then describes the methodology of using a PMSG connected to a voltage source converter and low pass filter to integrate the output of a small wind turbine into a small grid. The document concludes that using small electrical machines modified as PMSGs can provide a low-cost alternative for generating power from small wind turbines and connecting it to small grids or microgrids.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Theory and Analysis of Three Phase Induction Motor using Written Pole TechnologyIOSRJEEE
Three phase induction motors are employed in almost all the industries because of its simple construction and easy operation. Efficiency of the induction motor is affected by its fixed losses and variable losses which mainly depend on the input supply voltage and load current respectively. An attempt is made to minimize the iron losses by using the permanent magnet ferrite. A new Three Phase Induction Motor Using Written Pole Technology is proposed in this paper whose stator consists of two three phase windings accommodated in the same core and rotor is used as squirrel cage rotor with ferrite material on its periphery. Shaft loads are categorized as low, medium and high, Stator coils are energized through a controller based on the load demand. When compared to conventional induction motor, the motor efficiency and power factor are improved. Another approach of this machine is that the ferrite layer on the rotor periphery will reduce the motor losses which results in improving the motor efficiency. In this motor, one windings (main winding) is designed for the 238 volt ac voltage while the second winding (exciter winding) is designed for 8 volt ac voltage. Experimental result ensures the considerable increase in the efficiency and power factor.
SIMULATION AND ANALYSIS OF PERMANENT MAGNET SYNCHRONOUS GENERATOR FOR RENEWAB...IAEME Publication
This paper deals with the simulation of dynamic model of permanent magnet synchronous generator (PMSG) in D-Q axes of the rotor rotating reference frame. The iron core losses and stray load losses of the machine are taken into account. The iron core losses are represented by iron core resistance connected in parallel with magnetizing inductance and then reflected into the stator side as a voltage drop to prevent increasing the number of differential equations in the model. The modified equivalent circuit can deal with all machine parameters without losing the accuracy of generator performance calculations. The modified equivalent circuit can be used as an efficient tool for analysis, design, and vector control algorithm of this type of generator, especially in renewable energy utilization. The model is executed by Matlab Simulink and very good results are obtained and compared with the results of the experimental model to display the validity and accuracy of the proposed dynamic model.
Modeling and Simulation of Three Phase Induction Machine Using Written Pole T...IOSRJEEE
Three phase induction motors are employed in almost all the industries because of its simple construction and easy operation. Efficiency of the induction motor is affected by its fixed losses and variable losses which mainly depend on the input supply voltage and load current respectively. An attempt is made to minimize the iron losses by using the permanent magnet ferrite. A new Three Phase Induction Motor Using Written Pole Technology is proposed in this paper in which stator consists of two three phase windings accommodated in the same stator core and rotor is used as squirrel cage rotor with ferrite material on its periphery. Shaft loads are categorized as low, medium and high, Stator coils are energized through a controller based on the load demand. In this study, it is suggested to operate the machine with flat efficiency characteristics, irrespective of shaft load. When compared to conventional induction motor, the motor efficiency and power factor are improved. Another approach of this machine is that the ferrite layer on the rotor periphery will reduce the motor losses which results in improving the motor efficiency. In this motor, one windings (main winding) is designed for the 238 volt ac voltage while the second winding (exciter winding) is designed for 8 volt high frequency ac voltage. Experimental result ensures the considerable increase in the efficiency and power factor. The aim of this paper is to analyze and simulate performance of a 1Hp three phase induction motor using written pole technology using the well known Park’s transformation. A three phase squirrel cage machine is reconfigured and modeled into a two three phase stator winding accommodate in same stator core of the same volume as the three phase machine. Different tests are carried out on the novel machine to determine machine parameters. Simulation results, that predicts the dynamic performance of the machine using ANSYS, at start up are presented and discussed.
Review on stability analysis of grid connected wind power generating system1prjpublications
This document reviews modeling of the doubly fed induction generator (DFIG) for stability analysis of grid connected wind power systems. It discusses various DFIG models proposed in previous research for stability studies. The DFIG model consists of a wound rotor induction generator connected to the grid via a back-to-back voltage source converter. The converter allows variable speed operation and improved stability control compared to other induction generators. The document also examines effects of wind power on power system stability and methods to enhance stability through DFIG control strategies.
Review on stability analysis of grid connected wind power generating system1prjpublications
This document reviews modeling of the doubly fed induction generator (DFIG) for stability analysis of grid connected wind power systems. It discusses various DFIG models proposed in previous research for stability studies. The DFIG model consists of a wound rotor induction generator with a rotor circuit connected to a back-to-back voltage source converter. The converter allows variable speed operation and improved stability control compared to other induction generators. The document also examines effects of increased wind power penetration on power system stability and methods to enhance stability.
Study of DFIG Connected to Grid using Wind Energy SystemIRJET Journal
This document summarizes a study on connecting a doubly fed induction generator (DFIG) driven by a wind turbine to the electric grid. It begins by introducing DFIGs, which are commonly used in large wind farms because they can supply power at constant voltage and frequency despite fluctuations in wind speed. A DFIG has grid-connected stator windings and rotor windings connected to the grid via a back-to-back converter. This converter, consisting of a rotor side converter and grid side converter linked by a DC bus, controls the rotor currents to maintain constant grid frequency regardless of rotor speed variations from changing wind. The document then discusses issues with integrating wind power, such as voltage variations and stability, before describing the basic components
This document discusses different types of wind turbine generators (WTGs) including direct current (DC), alternating current (AC) synchronous and asynchronous generators, and switched reluctance generators. It provides details on the principles and technologies of each type, including their advantages and disadvantages. Some key considerations for WTG design are also outlined such as choice of machine, drive train type, rated speeds and torques, cooling arrangement, and cost.
IRJET- Improvement of Wind Turbine DFIG using Fault Ride Through Capability T...IRJET Journal
This document discusses techniques for improving the fault ride-through capability of doubly fed induction generator (DFIG) wind turbines. It begins with an introduction to DFIG wind turbines and discusses challenges during grid faults. It then presents an active crowbar protection system to reduce high rotor currents and voltages during faults. The crowbar works by bypassing the rotor circuit when faults are detected. Fault detection methods like current threshold monitoring are also examined. Simulation results show the crowbar technique helps DFIG wind turbines stay connected to the grid during faults and resume normal operation quickly after faults clear. The paper concludes the crowbar protection and control strategies improve the low voltage ride-through capability of DFIG wind turbines.
Open-End-Winding Permanent Magnet Synchonous Generator for Wind Energy Conver...Naila Syed
Recent trend in Wind energy conversion system which helps in understanding how the control systems and power energy systems can be interfaced to make the best use of wind energy.
The document discusses different types of wind turbine generators used in wind energy technology. It covers the fundamentals of wind power generation and describes various generator and motor types used - including induction motors, permanent magnet synchronous generators, squirrel cage induction generators, wound rotor induction generators, and doubly fed induction generators. The document also discusses high temperature superconducting wind turbine generators and provides comparisons of advantages and disadvantages of different generator types.
POWER FACTOR CORRECTION OF A 3-PHASE 4- SWITCH INVERTER FED BLDC MOTORvanmukil
This document provides an overview of brushless DC motors. It discusses their construction, operation, and applications. Key points include:
- BLDC motors have electronic commutation rather than mechanical brushes. They provide linear torque-speed characteristics like brushed DC motors.
- They consist of a radially magnetized permanent magnet rotor and phase windings on the stator. Electronic controllers and position sensors enable synchronized commutation.
- BLDC motors are widely used in applications like computers, appliances, electric vehicles due to their reliability, efficiency and power density compared to brushed DC motors.
- The document reviews BLDC motor components, control methods, torque production principles and common configurations like three-phase
1) A new converter topology for closed loop speed control of a switched reluctance motor is proposed, consisting of half-bridge IGBT modules and SCRs.
2) The proposed converter topology aims to improve upon the conventional asymmetric bridge converter by enhancing utilization of switching devices.
3) Simulation results in MATLAB/Simulink validate the operation of the proposed converter topology in both open loop and closed loop configurations for driving a switched reluctance motor.
This document describes a proposed design for a maglev wind turbine that uses magnetic levitation to generate power more efficiently than conventional wind turbines. Some key points:
- The maglev wind turbine uses magnetic levitation to suspend the turbine blades, eliminating friction and allowing them to spin more freely. This can increase power output by 30% over standard wind turbines.
- The design places magnets on the turbine blades and base such that magnetic repulsion keeps the blades levitated. An axial flux generator then converts the kinetic energy to electricity.
- Testing showed the maglev design outputs more power than an identical conventional turbine across a range of wind speeds, requiring less maintenance and space than standard designs.
-
Stabilization and Frequency Regulation in Microgrid by Controlling Pitch Angleijtsrd
PID controller based pitch angle controller for the frequency regulation and active power control in a wind turbine and diesel engine powered hybrid power system, is presented in this paper. For testing the prosed controller, variable wind speed pattern is used for realization of real time wind behavior. Furthermore, the variable load is also connected to the hybrid power system to test the efficacy of the prosed controller. The system is modelled and simulated in MATLAB environment and results obtained are compared with and without pitch angle controller. The frequency deviations in PID based pitch angle controller is less than the without controller. Aman Malik | Kavita Sharma "Stabilization and Frequency Regulation in Microgrid by Controlling Pitch Angle" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33303.pdf Paper Url: https://www.ijtsrd.com/engineering/electrical-engineering/33303/stabilization-and-frequency-regulation-in-microgrid-by-controlling-pitch-angle/aman-malik
This document analyzes a DFIG (Doubly Fed Induction Generator) based wind energy system with grid integration under normal and abnormal conditions. It models the DFIG, turbine, pitch control system, and grid side and rotor side converters in detail. Simulation results in MATLAB show the system performs satisfactorily under normal conditions by efficiently injecting power to the grid while maintaining synchronization. The analysis proves the control strategy is suitable for DFIG grid integration.
1) The document describes the growth and decay of charge in an RC circuit. When the switch is closed, the capacitor begins to charge exponentially according to the equation Q = Q0(1 - e-t/RC). When the switch is open, the capacitor begins to discharge exponentially as Q = Q0e-t/RC.
2) The time constant, RC, represents the time it takes for the charge on the capacitor to reach 63.2% of its maximum value Q0 during charging or 36.8% during discharging.
3) The rate that the charge changes on the capacitor depends inversely on the time constant, with a larger RC leading to slower changes in charge.
When a capacitor and resistor are connected in series to a voltage source via a switch, the capacitor will charge exponentially when the switch is closed and discharge exponentially when the switch is opened. The time constant (τ) of the circuit, which is equal to the product of the resistance (R) and capacitance (C), determines the rate of charge and discharge. Specifically, it represents the time required for the capacitor to reach 63.2% of its maximum charge during charging or 36.8% of its maximum charge during discharging. The current through the circuit also follows an exponential decay/growth formula determined by the time constant τ.
1) Ramsden's eye piece consists of two plano-convex lenses with equal focal lengths placed a distance of 2f/3 apart to minimize chromatic aberration.
2) The focal length of the equivalent lens is 3f/4. For the final image to appear at infinity, the equivalent lens must be placed a distance of f/2 from the field lens.
3) The six cardinal points are: the first principal point at f/2 from the field lens, the second principal point at -f/2 from the eye lens, the first focal point at -f/4 from the field lens, and the second focal point at f/4 from the eye lens. The nod
1) According to quantum mechanics, it is impossible to simultaneously determine the exact position and momentum of a particle. This uncertainty is called the Heisenberg uncertainty principle.
2) The Heisenberg uncertainty principle can be expressed as ∆x∆p≥ħ/2, where ∆x is the uncertainty in position, ∆p is the uncertainty in momentum, and ħ is the reduced Planck constant.
3) The document provides two examples to illustrate the Heisenberg uncertainty principle - an experiment involving photons colliding with electrons, and the diffraction of electrons at a single slit. In both cases, calculating the product of the uncertainties in position and momentum yields Planck's constant, ver
1) Fresnel's theory of diffraction explains that diffraction occurs due to the interference of secondary wavelets produced by unobstructed portions of the wavefront.
2) When considering the diffraction pattern at a point P, Fresnel divided the wavefront into concentric half-period zones centered on the point's pole O. The contribution of each zone to the intensity at P depends on the zone's area and distance from P.
3) For a large number of zones, the total intensity at P is approximately one fourth of that due to the first zone alone, explaining the dimming of light in diffraction patterns.
This document discusses the use of breadboards for prototyping electronic circuits. It explains the layout of buses and groups on a breadboard which allow components to be connected. Examples are given of wiring resistors, transistors, and integrated circuits on a breadboard. Guidelines are provided for effective breadboarding, such as using appropriate wire gauges, adding bypass capacitors, checking for errors, and limitations for certain circuit types. The document is intended to teach basic breadboarding skills for prototyping circuits.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
KuberTENes Birthday Bash Guadalajara - K8sGPT first impressionsVictor Morales
K8sGPT is a tool that analyzes and diagnoses Kubernetes clusters. This presentation was used to share the requirements and dependencies to deploy K8sGPT in a local environment.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
1. DIRECT DRIVE WIND TURBINE
Mr.Shivanand.V.Angadi
Jagadguru Tontadarya College Of Arts,
Science And Commerce Gadag- Betageri
shivanand1964@gmail.com
ABSTRACT
Main reason for the adoption of wind energy system. Classification of wind turbines
based their structure, speed and motors used in the WPP’s. The detailed theory of direct
drive wind turbine including their configuration, working principle and modelling. The
comparative results of direct drive WT’s in terms of merits and demerits are discussed.
Keywords:
wind turbine direct drive turbines, variable speed constant speed, induction generator, double fed
induction generator.
1. INTRODUCTION
Electric power is the necessity of human life now a day. since many decades’ people relay
on fossil fuels such as petrol, diesel, coal etc for the generation of electric power. From
the beginning of 20th
century people start of thinking alternative resources of energies,
they found nonconventional energy sources like solar energy, wind energy, biomass,
geothermal etc. The wind energy is ultimately a promising one among the listed resources,
because the wind potential abundance, abundance of suitable landscapes, vital
technological developments in wind turbines and less possible impacts on human life.
In this presentation, direct drive wind turbine is discussed. The wind turbines are
classified into different types such as type-A, type-B, type-C and type-D. Again they are
classified as fixed speed and variable speed types. They further subdivided into SCIG,
WRIG, DFIG and PMSG types. Here both type of direct drive wind turbine is discussed.
2. RESULT :
Conclusion: The comparative study reviewed that the variable speed operation of WPPs, not only
the electrical power extraction is enhanced but also the stresses on the mechanical structure are reduced. The
energy from the wind gusts is partially transferred into the acceleration of the wind turbine rotor and therefore,
2. there is no need to reduce the blade pitch angle instantaneously. Moreover, there is a greater control of active
and reactive power and lesser acoustic noise.
DIRECT DRIVE WINDTURBINE
INTRODUCTION:
This topology was the first in Type-D WPP with variable speed WRSG category and
pioneered by Enercon who harnessed the widely variable wind speeds (see Figure 1) in
early 1990s. The WRSG in this WPP has a separately excited salient pole rotor directly
connected to the wind turbine rotor hub by a slow moving shaft. The large multipole
stator in the shape of a ring is fastened onto the yoke ring whereby the WRSG is also
called as ring generator (or annular generator).
Working Principle
In this topology, the RPM of a multipole generator is same as the wind turbine rotor. The
basic characteristic of the WRSG is that its rotor speed is always locked and in
synchronism with the stator rotating magnetic field. With varying wind speeds, the
voltage and frequency at the generator terminals are also not constant and they vary. As
these do not match with that of the grid voltage and frequency, the WRSG is fully
decoupled by the fully rated PEC and the varying electric power from the stator is
connected to the electric grid after being treated in the four-quadrant operating PEC, as
discussed in earlier sections.
Voltage control is affected by controlling the magnetizing level of WRSG, i.e., high
magnetizing level results in high voltage and production of reactive power. In other
words, it can be said that an ideal WPP has the ability to export and import net reactive
power at full load over a range of grid voltages.
The electronic controller of the direct-drive WPP continuously monitors the grid
parameters and if the grid power factor becomes low, without use of any capacitors, the
PEC will automatically feed reactive power to the grid to improve the power factor.
3. Figure 1 Type-D Direct Drive WPP with Variable Speed WRSG: The generator
rotor has field coils that are separately excited, by a separate DC supply through
slip rings and brushes. The full power from stator is fed to the full rated PEC.
Direct-drive WPPs can continue to operate at lower power capacities (see Figure 2) if
the grids do not have temporary or long term overcapacities. Setting a power gradient in
direct-drive WPPs (a salient feature of this type of WPP) helps in adjusting the power
gradient regulation (see Figure 3) and in optimally suppressing the flicker and voltage
fluctuations even in very weak grids.
Figure 2 WRSG Power Regulation: Possible direct-drive WPP operation when grids do not
have temporary or long term overcapacities.
4. Figure3 WRSG Power Gradient Regulation dpldt. Possible in direct- drive WPPs to
minimize the flicker and voltage fluctuations.
With recent developments, fault-ride-through capability (that means it remains connected
to the grid even during grid faults) to a limited extent is provided with WRSGs, a feature
which is very much required by the grid operators. Power ramp regulation is also being
provided with WRSGs. However, owing to the presence of PECs in the stator connections to
the grid, this type of generator cannot contribute much to system inertia.
DIRECT-DRIVE WPP WITH VARIABLE SPEED PMSG
One of the main drawbacks of Type-D direct-drive WPP with WRSG is the high
maintenance of slip rings and brushes. This problem is solved by low speed direct-drive
WPP with PMSG (see Figure 4), Its inherent self-excitation characteristic lowers the
maintenance problem to a great extent. Since the modern rare earth.
Figure 4 Type-D Direct-drive WPP with PMSG: Since the generator rotor has permanent magnets, it is self-excited and therefore,
does not require separate field coils and separate DC supply to excite them, thereby eliminating the need for slip rings and brushes.
permanent magnets have the ability to produce large quantities of magnetic flux within a very
5. small volume and geometry, they permit high pole count designs and complement the low speed direct-drive
WPP application. For the same rating, a PMSG has a relatively smaller volume than a WRSG due to the
absence of windings in the generator rotor, leading to slightly lower weight which results in a lower THM.
Working Principle
This PMSG topology is more competitive because it can have higher pole count of 60 or more
poles as compared to a conventional WRSG. The permanent magnet rotor of the radial flux PMSG is directly
connected to the varying speed, WPP rotor (between 7 RPM-20 RPM, depending on the rotor diameter size).
Larger the diameter, the slower will be the speed of rotation. Direct-drive WPP with PMSG can have
following two different constructions:
• Outer stator coils and inner rotor mounted with permanent magnets (see Figure 4 ).
• Inner stator coils and outer rotor mounted with permanent magnets (see Figure 5).
Figure 6 Type-D Direct-driveWPP with Inner PMSG Rotor: Nacelle length is shorter due to
absence of gearbox in direct-drive WPPs and the multipole generator rotates at the same
slow speed as the rotors.
Figure 6 depicts the typical external stator coils and internal permanent magnet rotor
constructional design of 1.5 MW Leitwind Type-D direct-drive WPP with PMSG.
Whereas, Figure 3.20A, depicts the typical outer rotor and inner stator constructional design
6. of 1.5 MW Vensys design (licensed to Regen Power-tech, India' type-D direct-drive WPP with
PMSG.
Figure 7 Type-D Direct Drive WPP with Outer PMSG Rotor: The radial flux strategy forms the externally
rotating rotor frame of this PMSG. This helps to increase the torque due to the increase in
bore diameter.
Irrespective of the type of permanent magnet rotor construction (inner or outer), the stator of the
radial flux PMSG has a three-phase symmetrically distributed Stator winding wound around a large number of poles
(multipole) to adjust the speed of slow moving rotor. During normal operation of the WPP, the rotor speed the PMSG is
always locked to the stator exactly proportional to the frequency of the electrical grid. Changes in load cause the
PMSG rotor to advance or drop back a few degrees (called the load angle δ) from the rotating magnetic field of me
stator supplied by the grid. If the torques or currents necessary to accomplish this speed exceed the rated PMSG rating, then
the circuit breakers will open,
there by disconnecting it from the grid in order to protect the generator from getting damaged.
There is no significant starting current when the PMSG is supplied by a PEC and the relation between
the starting and the nominal currents is very low. This is one of the greatest asset of the PMSG that the o utput power is
sinusoidal which is the requirement of a grid operator. There is no exchange of reactive power between the PMSG and GSC
during normal operation; ii only absorbs electric power.
The control of reactive power and the voltage in the WPP equipped with PMSG is defined
by the control system of GSC. Transfer of electric power is through the IC link bus of the PEC. However, the permanent
magnet excitation cannot be controlled as in WRSG electromagnets and so, the output voltage falls, as load is increased.
Therefore, a voltage regulator is needed in most applications. However, the PEC between PMSG stator and grid solves this
problem to a certain extent. In the case of a WRSG, the reactive power is not a problem, since it is produced
internally using the electromagnetic field winding.
One issue for the PMSG regarding the PECs in the stator connections to the grid is that it
cannot contribute much to the system inertia. Another issue is cogging. It is an inherent
characteristic peculiar to slotted PMSGs which is not much of an issue in WRSG, and hence,
7. needs to be taken care during design. Modern WPPs with PMSG fault-ride-through capability
(to remain connected to the grid during system faults), exists to a limited extent, subject to
their rating.
Therefore, PMSG solution yields a higher efficiency throughout the whole variable speed
operation range that results in smaller power fluctuations and lower rotor noise even during
partial power operation.
SALIENT FEATURES OF TYPE-D DIRECT-DRIVE WPP
Following are some of the positive features of type-D direct-drive WPP with synchronous
generator:
i. Absence of gearbox maintenance and failures.
ii. The rotor blades and the large size generator have considerable inertia that functions as a
flywheel (absorbing and storing the energy temporarily as a buffer) smoothing out the aerodynamic torque
fluctuations that results in less mechanical stress on the drive train, especially during the blade passing frequency.
iii. There is a reduced loading on mechanical components. Lesser fatigue loads on blades,
tower and different parts of the WPP, as wind gusts can be absorbed by the inertia of
the WPP creating an elasticity which reduces torque pulsations that results in lesser
electric power fluctuations as well.
iv. These WPPs have lesser number of bearings and couplings.
v. Net energy capture at partial load (which is quite common, as the wind does not
always blow at rated speed conditions for full load operations) is maximized by optimal
TSR operation by Type-D WPPs, thereby maximizing the aerodynamic efficiency of the WPP rotor.
vi. The pitch control can be simpler because the time constant can be longer for variable
speed operations.
vii. These WPPs can easily comply with the requirements of grid operators, as the active
and reactive power can be controlled and large wind farms can even act as a source of
reactive power to compensate poor power factor of other consumers on the electrical
network particularly in remote locations and offshore WPPs.
viii. These slow rotating WPPs produce lesser tip noise at low wind speeds.
ix. Due to the full rated PEC (in contrast to one-third rated PEC of type-C WPP), it can
deliver more reactive power (100%) to support a stable voltage level.
x. Voltage flicker problems are reduced.
xi. Although the electrical efficiency decreases due to the losses in the PECs that are
8. essential for Type-D WPPs, the increase in rotor efficiency outweighs the losses of
the PEC.
xii. Fault-ride-through (FRT) is possible.
LIMITATIONS TYPE-D DIRECT-DRIVE WPPS
i. Type-D WPPs can only be connected to the grid when frequency, phase position and
voltage of the power produced are in synchronism with the grid.
ii. Absence of gearbox is offset by a larger PEC (requiring greater cooling arrangements)
with more complicated circuits for which expert maintenance personnel is difficult to
get on time, as many of the wind farms are in remote and rural locations.
iii. Type-D WPPs due to commutation losses, continuously lose 1% to 2% of the nominal
power in generating and maintaining the magnetic field. Additional maintenance and
heat dissipation is required.
iv. The PECs are sensitive to voltage dips caused by faults and/or switching. IGBT
switches in the PECs are very sensitive to thermal overloads, over currents and over
voltages. In such cases, to prevent their damage, the PEC may block, i.e., stop
switching. Converter blocking may lead to disconnection of the WPPs which is not
acceptable to most of the TSOs.
v. As the power of the WPPs increase in the megawatt range, direct-drr. - WPPs become
heavier and more expensive generator. Their top head mair is relatively much more
than that of geared WPPs.
vi. As compared to a SCIG of similar size, the WRSG is mechanically at: electrically more
complicated.
There is a substantial cost difference between the constant speed WPPs an: variable speed
WPPs. If proper cable shielding is not done, the electrical noise can create problem; for control
signals within the WPP. With the use of optical fiber cables, this problem is being minimized.
3. CONCLUSIONS
The comparative study reviewed that the variable speed operation of WPPs, not only the
electrical power extraction is enhanced but also the stresses on the mechanical structure are reduced. The
energy from the wind gusts is partially transferred into the acceleration of the wind turbine rotor and therefore,
there is no need to reduce the blade pitch angle instantaneously. Moreover, there is a greater control of active
and reactive power and lesser acoustic noise.
Acknowledgement
9. This work was supported and funded by UGC as the part of minor research project under UGC XIIth
plan.
Biography (Times New Roman 10) (alternatively)
Text (Times New Roman 10)
References (Times New Roman 12)
[1] T. Borowski, World Scientific News 7 (2015) 20-52.
[2] Z. S. Hamidi, N. N. M. Shariff, C. Monstein, World Scientific News 52 (2016) 70-80.
[3] Dinendra Raychaudhuri, Sumana Saha, Souvik Sen, Dhruba Chandra Dhali, World
Scientific News 20 (2015) 1-339
[4] G. Thirunarayanan, World Scientific News 53(3) (2016) 138-156.
[5] C.G. Swain, E.C. Lupton Jr., Journal of the American Chemical Society 90 (1968)
4328-4337.
[6] W. F. Winecoff and D.W. Boykin Jr., J. Org. Chem. 37(4) (1972) 674-676.
[7] B. O. Johnson, Journal of Environmental and Biological Science 12(4) (2010) 48-59.
[8] L. F. Crofton, B. J. Horne & G. O. Miller, American Journal of Respiratory Diseases
10(11) (2013) 456-467.
[9] G. Fatima, M. Ahamed, W. Rehman, International Journal of Business and Social
Sciences 3(7) (2012) 203-208.
[10] A. Patwardhan & R. P. Athalye, Genus 21(4) (2010) 505-511.
[11] P. H. Wimberger, Biol. J. Linn. Soc. 45 (1992) 197-218.
[12] Jack L. Jenkins, The English Journal 55(9) (1966) 1180-1182.
[13] M. Ferber, English Literary Renaissance 20(3) (1990) 431-464.
[14] etc. ….
10. This work was supported and funded by UGC as the part of minor research project under UGC XIIth
plan.
Biography (Times New Roman 10) (alternatively)
Text (Times New Roman 10)
References (Times New Roman 12)
[1] T. Borowski, World Scientific News 7 (2015) 20-52.
[2] Z. S. Hamidi, N. N. M. Shariff, C. Monstein, World Scientific News 52 (2016) 70-80.
[3] Dinendra Raychaudhuri, Sumana Saha, Souvik Sen, Dhruba Chandra Dhali, World
Scientific News 20 (2015) 1-339
[4] G. Thirunarayanan, World Scientific News 53(3) (2016) 138-156.
[5] C.G. Swain, E.C. Lupton Jr., Journal of the American Chemical Society 90 (1968)
4328-4337.
[6] W. F. Winecoff and D.W. Boykin Jr., J. Org. Chem. 37(4) (1972) 674-676.
[7] B. O. Johnson, Journal of Environmental and Biological Science 12(4) (2010) 48-59.
[8] L. F. Crofton, B. J. Horne & G. O. Miller, American Journal of Respiratory Diseases
10(11) (2013) 456-467.
[9] G. Fatima, M. Ahamed, W. Rehman, International Journal of Business and Social
Sciences 3(7) (2012) 203-208.
[10] A. Patwardhan & R. P. Athalye, Genus 21(4) (2010) 505-511.
[11] P. H. Wimberger, Biol. J. Linn. Soc. 45 (1992) 197-218.
[12] Jack L. Jenkins, The English Journal 55(9) (1966) 1180-1182.
[13] M. Ferber, English Literary Renaissance 20(3) (1990) 431-464.
[14] etc. ….