Permanent Magnet Synchronous Generator (PMSG)
Abstract
In the modern society, the overwhelming trend is the adoption and implementation of the concept of variable speed wind turbine in the running of the permanent magnet synchronous generator. Wind energy is gaining popularity in the modern society because of the competitive cost and environmental protection or benefits. Clean and economical characteristics of the wind energy make it vital for the survival of the humanity in the future aspects. Operation of the controlled wind energy converter in the variable speed mode is essential in the achievement of the maximum power. The Permanent Magnet Synchronous Generator possesses surface-mounted permanent magnets without the damper winding in the provision of excitation to the grid. The modern society considers adoption and consumption of the energy relating to the conventional fossil fuel as a contributor towards global warming and environmental deterioration.
Introduction
In the modern society, the overwhelming trend is the adoption and implementation of the concept of variable speed wind turbine in the running of the permanent magnet synchronous generator. Wind energy is one of the potential sources of energy for the survival of the future world through its relevant advantages or benefits to the environment. It is essential to enhance the safety of the humanity through adoption and application of clean, safe, and economical or cost effective nature of energy. The present world’s target is to achieve or utilize the wind energy in relation to production of about 12 percent of the global electricity. Permanent Magnet Synchronous Generator refers to a mechanical generator, which utilizes permanent magnet in the process of providing excitation rather than the application of the coil to execute the functions. In the commercial context, synchronous generators dominate through the provision of electrical energy.
These types of generators are applicable in the conversion of the mechanical power output in relation to steam turbines, hydro turbines, reciprocating turbines, and wind turbine towards the electrical power with reference to the grid. The name draws from the fact that the speed of the rotor must match or be in accordance with the supply frequency (synchronize with the supply frequency). Permanent magnets are applicable in the production of the magnetic field within the rotor in the permanent magnet generators. Permanent Magnet Synchronous Generator operates without the DC supply vital for the excitation circuit. They also have the ability to function without the slip rings and the relevant brushes for contact.
Literature Review
Transient Stability Analysis of Permanent Magnet Variable Speed Synchronous Wind Generator
Clean and economical characteristics of the wind energy make it vital for the survival of the humanity in the future aspects. Application of wind energy will enable the world to achieve the 2020 goal of generating 12 percent of the global electricity through wind components (Muyeen et al, 2007). It is vital for the modern society to evaluate transient stability of the wind turbine generator system because the prospective networking of the wind generators in the modern and postmodern worlds. The evaluation of the stability in relation to transient has been the focus of study of numerous literature materials. In 2004, the market share of the Wind Turbine Generator System was approximately 60 percent thus common feature within the modern society (Muyeen et al, 2007).
In Permanent Magnet Synchronous Generator, the provision of excitations is under the influence of the permanent magnets rather than the field winding. Permanent magnets possess features such as large air gaps applicable in the reduction of the flux linkage even in the context of machines with multiple or numerous magnetic poles. This results into the manufacturing of the low rotational speed generators through application of the synchronism of the size and power rating. Permanent Magnet Synchronous Generator has the ability to omit the gearbox because of the low rotational peed thus reduction in the cost. In the enhancement of the transient stability of the Variable Speed Wind Turbine and Permanent Magnet Synchronous Generator (VSWT-PMSG), it is essential to control the power converters of the Permanent Magnet Synchronous Generator in an effective approach (Muyeen et al, 2007).
Pw=0.5 p π R2 Vw3 Cp (λ, β) expresses the mechanical power extraction in relation to wind.
Pw symbolizes the extracted power from the wind, p refers to the air density (kg/m3), R is the blade radius (m), Vw illustrates the speed of the wind in meters per second, and Cp is the power coefficient that reflects the function of both tip speed ratio and blade pitch angle in the form of (λ, β). Proposed control of the converters has the ability to enhance the transient stability of the Variable Speed Wind Turbine and Permanent Magnet Synchronous Generator (VSWT-PMSG) under symmetrical and unsymmetrical fault conditions. The proposed control of the converters is also capable of providing maximum power to the grid and enhances the control of the reactive power in relation to maintenance of the terminal voltage of the grid constant (Muyeen et al, 2007).
Control of a Permanent Magnet Synchronous Generator Used in a Variable Speed Wind Energy System
Operation of the controlled wind energy converter in the variable speed mode is essential in the achievement of the maximum power. The generator side inverter has the ability to control the speed of the wind turbine in the context of connected grid and generator. The generator operates in the optimal working point within the preferred control concept. This act aims at minimizing the losses from the perspective of the generator and relevant electronic devices or power equipment. The application of the Permanent Magnet Synchronous Generator relates to the employment of 100 kW and effective consideration of the MW range (Stiebler, 2001).
A Model of Permanent Magnet Synchronous Generator
The Permanent Magnet Synchronous Generator possesses surface-mounted permanent magnets without the damper winding in the provision of excitation to the grid. This indicates that the steady-state voltage equations for the generator in the dq-components are expressed as follows:
Űd = RSid – wφq + φd, (1)
Űq = R + wφd + φq, (2)
φd = Ldid + φf, (3)
φq = Lqiq (4)
In the above equations ud and uq refer to the terminal voltages, id and iq represent the stator currents, Rs represents the stator winding resistance, Ld and Lq illustrate the concept of the stator direct and quadrature inductances, and φf is the denotation of the excitation influx linkage (Stiebler, 2001). It is essential to control the stall-controlled WEC through the application of the permanent magnet synchronous generator. This indicates that the WEC operates within the optimal working point regardless of the measurement of the wind velocity or speed of wind. This undergoes under the influence of the grid and the generator maintained at sinusoidal.
A Maximum Power Control of Wind Generator System Using a Permanent Magnet Synchronous Generator and a Boost Chopper Circuit
The modern society considers adoption and consumption of the energy relating to the conventional fossil fuel as a contributor towards global warming and environmental deterioration (Kenji et al, 2002). This demands the transformation in the source of energy to adopt and implement the natural sources with the aim of replacing the conventional energy sources. The need to protect environment and humanity leads to the proposal of source of energy such as wind force, wave force, solar energy, and geothermal energy. In order to utilize the wind energy that changes constantly, it is essential to adopt the wind generator systems and control measures. This enhances the ability to utilize wind energy effectively and efficiently within the modern society thus reduction of losses and costs of the provision of electricity energy. Application of the generators applied to the extraction of wind power enjoys the benefits or solidity and cheaply in relation to the cost of maintenance. Permanent Magnet Synchronous Generator is applicable in the extraction of wind energy because of the low factor of power and minimal influence of the excitation source of AC like in other induction generator (Kenji et al, 2002).
Permanent magnet field excitation three-phase synchronous generator is applicable in the process of realizing effectiveness and efficiency in relation top the conversion of power. Rectification of the AC power is possible through the three-phase diode rectifier circuits within the DC power factor. The application of permanent magnet synchronous generator guarantees effectiveness and efficiency because of the minimal requirement of the power excitation source. The taking output of the generated output is possible with ease in relation to the application of permanent magnet synchronous generator because of the proportional existence between the electromotive force and the rotational speed (Kenji et al, 2002).
Optimal Design of Permanent Magnet Synchronous Generator for Wind Energy Conversion Considering Annual Energy Input and Magnet Volume
Permanent Magnet wind generators are applicable in relation to variable speed, and wind energy conversion systems. This operation differs from the induction generators that are applicable in the constant, semi-constant, speed, and relevant geared systems. The variation of the speed of generator and wind velocity demands application of the wind generators to enhance performance at the peak power and achievement of maximum energy from the wind force. It is also possible to eliminate the gearbox in between the turbine and the wind turbine. Elimination of the gearbox is advantageous in relation to minimization of complexity of the system, evasion of lubrication, reduction of the extra losses or costs, and essence of noise (Faiz et al, 2008). Despite the fact, induction generators are powerful and cost effective in their application of energy generation, it is ideal to note that they require bulky and expensive capacitance vital for the generator mode operation and performance of the excitation control.
Induction generators need to solve the essence of over-voltage and over-current difficulties in the generation of electricity energy. Permanent Magnets are available and cost-effective thus the emerging popularity over the induction generators. The advantages of the permanent magnet generators relate to simple design of the rotor, reduction of slip rings, and excitation of the generator. There is also the essence of low temperature rise and constant improvement of the effectiveness and efficiency in the generation of electricity form of energy. The permanent magnet synchronous generators are classified under four crucial groups: axial flux, radial flux, tooth pole, and cross-field generators (Faiz et al, 2008). Research studies indicate that radial flux and axial flux categories are the most common types of the permanent generators. Radial influx generators (inner rotor) are most common in the generation of electricity energy because of low construction and cost of procurement and maintenance (Gieras et al, 2008).
Direct Torque Control Based Three Level Inverter-fed Double Star Permanent Magnet Synchronous Machine
The possibility to divide controlled power on the inverter legs proves to be the main advantage of multiphase drives. Multiphase are essential in the large systems such as the ship of electrical propulsion, locomotive traction, and electrical vehicles applications (Badreddine et al, 2012). This is because of the benefits over the three phase conventional aspects such as reduction of the amplitude of the torque pulsation, lowering of the DC, and higher reliability and effectiveness or efficiency. In the late 20th century, there was the adoption and implementation of the direct torque control as one of the high-performance in relation to the AC drives. The direct torque control is less sensitive to the aspect of parameters. It is also essential in the provision of high dynamic performance than in the context of the classical vector control (Badreddine et al, 2012).
Modeling of the Wind Turbine with a Permanent Magnet Synchronous Generator for Integration
Wind energy is gaining popularity in the modern society because of the competitive cost and environmental protection or benefits. This illustrates that wind energy is one of the best technologies in relation to the provision of sustainable supply of electricity energy for the development of the world. There are unique wind-application generators to facilitate the extraction of the wind energy (Ming Yin et al, 2007). These applications aim at enhancing the performance and efficiency of the models in the extraction of wind energy thus reduction of losses and cost. The main differences in the applications relate to the fixed and variable speed levels of the wind turbine-generator concepts. In the early stages of the development of wind energy, there was adoption and implementation of the induction generators in the wind farms. Low efficiency, poor quality of power, and cost proved to have adverse influences on the applications of the early induction generators within the wind farms (Ming Yin et al, 2007). Advancements in the excitation of wind energy led to the adoption of the permanent magnetic synchronous generators as the preferred technology (Lai, 2007). This led to the application of the variable speed thus enabling the operation of the wind turbines at the optimum tip-speed ratio. Variable speed of the wind turbine results in the effectiveness and efficiency of the optimum power factor.
Recommendation and Conclusion
Permanent magnets are applicable in the production of the magnetic field within the rotor in the permanent magnet generators. In Permanent Magnet Synchronous Generator, the provision of excitations is under the influence of the permanent magnets rather than the field winding. Permanent magnets possess features such as large air gaps applicable in the reduction of the flux linkage even in the context of machines with multiple or numerous magnetic poles. The permanent magnet synchronous generators are classified under four crucial groups: axial flux, radial flux, tooth pole, and cross-field generators (Faiz et al, 2008). The need to conserve the environment and safety of humanity calls for the adoption and implementation of wind energy. This relates to the influence of the conventional fossil fuels on the global warming and environmental degradation (Earnest, 2011).
References
Ming Yin et al. (2007).Modeling of the Wind Turbine with a Permanent Magnet Synchronous Generator for Integration. 1-4244-1298-6/07/$25.00 ©2007 IEEE.
Badreddine et al. (2012). Direct Torque Control Based Three Level Inverter-fed Double Star Permanent Magnet Synchronous Machine. Badreddine Naas et al. / Energy Procedia 18 ( 2012 ) 521 – 530
Jawad Faiz et al, (2008).Optimal Design of Permanent Magnet Synchronous Generator for Wind Energy Conversion Considering Annual Energy Input and Magnet Volume.
Muyeen et al, (2007). Transient Stability Analysis of Permanent Magnet Variable Speed Synchronous Wind Generator. Proceeding of International Conference on Electrical Machines and Systems 2007, Oct. 8~11, Seoul, Korea
Schiemenz M. Stiebler. (2001).Control of a Permanent Magnet Synchronous Generator Used in a Variable Speed Wind Energy System. 0-7803-7091-0 /01/$10’2001 IEEE
Kenji et al, (2002).A Maximum Power Control of Wind Generator System Using a Permanent Magnet Synchronous Generator and a Boost Chopper Circuit. 0-7803-7 156- 9/02/$10.000 2002 IEEE
Earnest, J., & Wizelius, T. (2011). Wind power plants and project development. New Delhi: PHI Learning.
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