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Variable speed wind turbines, with their many advantages compared to fixed speed wind
turbines, is very promising technology for large scale wind farms. This report presents
modelling and control strategies of variable speed doubly-fed induction generator (DFIG)
based Type-3 wind turbine where the stator is connected directly to the three-phase gri...
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... or electrical/ reactive breaking is sometimes used to further prevent rotor rotation above Pitch control technique is shown in Fig. 7. P cut-out ...
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This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the system that converts kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning and recycling. Offshore development and dig...
Citations
... DFIG's behavior under hypersynchronous and hypersynchronous winds will be examined by applying variable wind speeds. An improved control technique for 3 rd harmonic injected pulse width modulation DFIG-based wind turbines has been created [8]. Further, MATLAB/Simulink simulations will be used to analyze and quantify the performance of all of these components. ...
... A typical 1.5MW DFIG-based wind turbine was modeled using MATLB/Simulink and FAST. In [4], a Model of the DFIG-based variable speed wind turbine was presented, in which steady state operation and control of DFIG was investigated. The performance of Indirect Matrix Converter with improved control of the doubly fed Induction Machine was studied in [5]. ...
This paper is an analysis of a MATLAB/Simulink model of the Doubly-fed Induction Generation (DFIG)-based wind turbine and its evaluation. It covers the aero dynamic model, rotor and grid side control models and the model of the DFIG. Many authors have presented similar models but this paper develops a Simulink model of the DFIG by using the analytical equations of the DFIG instead of the single DFIG block contained in the Simscape library of the Simulink software. An adequate description of the solution of this analytical model is provided. The control strategy was also implemented using appropriate function blocks in the Simulink environment and some MATLAB scripts. This work evaluates the performances of rotor speed, DC link voltage, rotor active and reactive power and the grid current. The response of rotor speed after wind speed changed from 8 m/s to 10 m/s is provided. The DC link voltage is controlled to a constant value of 1150 V to keep rotor power constant while the reactive power of the rotor is regulated at 0 VAR thereby ensuring that no reactive power is exchanged with the grid. A rise in rotor active power with less torque was observed with the step change in speed. The grid current waveform was observed to be a 50Hz, 3-phase sinusoidal current with amplitude of 500 A Peak to Peak (pk-pk).
... A rotating three-phase phasor makes it challenging to run an AC machine continuously. When a reference frame rotates at the same speed as the stator flux, a three-phase (ABC) system can be split into two phases (d-q) using the Park's transformation [11]. Equations for flux are expressed as follows in terms: ...
Wind power conversion systems are becoming the most preferable alternate renewable energy source. Doubly Fed Induction Generator's utilization rotating parts in wind turbines is increasing with the wind power penetration to the electric grid. The observation becomes more noticeable when there are abnormal conditions within the electrical power system. In this paper, MPPT Controller is incorporated with DFIG through the MATLAB Simulink program is simulated. A conventional PI controller is tuned with Ziegler-Nichol's (Z-N) method and was implemented to the DFIG Control Block. The rotor-side converter (RSC) is utilized to regulate the power generated by the doubly-fed induction generator (DFIG), while the direct current (DC) bus voltage is controlled by the grid-side converter (GSC). The DFIG's angular and comparative angular speeds are used to generate the reference torque value in the MPPT controller. This improved the time response, output power, electromotive torque, and other current and voltage characteristics. A comparison was made between the output evaluation of the inbuilt controller and the output evaluation of the proposed controller. The MPPT with tuned PI Controller's results show that the suggested system, which uses DFIG coupled to a rotor, is accurate, dependable, and feasible.
Micro-grid has the capability of operating both in island mode and grid connected mode.
However, immediately after disconnecting from the grid mode, the frequency and voltages
deviates from their nominal values. The droop control is one of several control techniques
used in minimizing these deficiency. However, if the droop parameters are not properly
selected, the deviations will not be minimized to the barest minimum. Therefore, this work
aims to optimize the droop controller to ensure that the deviations during islanding and
during load changes are very minimal. To optimize the droop controller, a grasshopper
optimization algorithm is incorporated into the controller parameters, to ensure stability
during disturbances (islanding and sudden increase in the load). Simulations results
obtained from the developed scheme, showed an improvement over the results obtained when genetic algorithm was used for optimizing the droop controller. The developed scheme showed an improvement of 0.2104% for the frequencies during islanding and improvement was also made when the load was increased to 10kW. All simulations were carried out on MATLAB environment.
Solar energy is rapidly gaining importance as an alternative source of energy. To make
solar energy more viable, efficiency of solar panel system must be maximized. A feasible
approach to maximized the efficiency of the solar panel systems is the sun tracking. Though, the problem attributed with solar power is its direct dependent on light intensity. Photovoltaic (PV) panels are used to convert Sun energy (the amount of light intensity) to direct electrical energy. The microcontroller will control the whole tracking system. The Photovoltaic (PV) panels and light dependent resistor (LDR) are used as a sunlight sensor. This paper is about moving a solar panel along with the direction of sun light; it uses a motor to change the position of the solar panel, motor is controlled by Atmel 89c51 microcontroller, which detects the sun light using photocells and liquid crystal display (LCD) to display the charging voltage of the PV module at every point in time. Performance analysis of the solar tracker was tested at the Department of Electronics and Telecommunication Engineering Ahmadu Bello University Zaria, Nigeria and results showed that the power output of the photovoltaic (PV) system had 58.4 % improvement when compared with the traditional method of fixed solar. The overall failure rate is 17.811% or 103hr. The reliability of the device that operates for one year is 61%.
In radio and television business, adequate dissemination of information to the target
audience is often of primary importance. Phone in programs gained wide acceptance in the
last two decades and more especially with the growing passionate for reality radio. The
device is to serve as a unit for controlling incoming telephone traffic during a phone in
program in a radio or television studio. It also facilitates the function of an intercom system
between the presenter and the program director. A phone in program is a radio discussion
production where viewers or listeners are given the opportunity to contribute in the
discussion. The setup of the production allows two to three professionals discuss important
issues relevant to the society, whereby contributions outside the studio from the audience
through the telephone lines can be heard. In this paper, a microcontroller-based telephone
traffic control system is developed. The system is made up of two receiver sets and a system
that samples calls and then sends one call at a time to the presenter. The same system is able
to realize when the contributor is through with his contributions, so that another call that is
on hold can be released to the presenter. The work is targeted at controlling the
indiscriminate flow of calls from contributors outside the studio during the phone-in
production. The system is intended to be used in radio and television studios during phone -in programs as a valuable contribution to society. The Ahmadu Bello University (ABU)
/BBC Studio/FM station were established by the British Broadcasting Corporation, World
Service Trust -BBC WST. The Studio was commissioned on the 8th of June, 2005 with two
main components- training and transmission. The training component commenced in the
2004/2005 session with students from Mass Communication and Theatre and Performing
Arts Departments who wish to specialize in Radio Broadcasting.
