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Showing 4 results for Mohammadi
Mr. M. Mohammadi, Dr. M. Gitizadeh, Dr. J. Aghaei, Dr. A. Roosta,
Volume 1, Issue 2 (12-2012)
Abstract
In recent years, due to shortage of energy resources, use of new energies such as wind energy has been rising. Therefore, the study for the optimal use of these energy resources is very necessary. Nowadays, doubly fed induction generators (DFIGs) are used in modern wind power plants. Stability investigation of power system connected to DFIG is very essential. Static VAR compensator (SVC) and static synchronous compensator (STATCOM) are installed in parallel with transmission lines. The main applications of these compensators are fixing and adjusting of the voltage in a certain amount and stability improvement. Parameters tuning of these compensators is very important. In this research, at first, an appropriate way is suggested in order to choose the objective function for minimizing oscillations resulted from disturbances. Then optimal tuning of SVC and STATCOM control parameters will be done by genetic algorithm in the form of an optimization. Ultimately, efficiency of suggested methods will be considered in order to improve the stability of DFIG voltage, DFIG rotor speed, DFIG active power and the rotor speed of synchronous generators. This topic is evaluated and analyzed in a sample network with considering and comparison of results in the presence and absence of SVC and STATCOM. All simulation and optimization steps are done by the MATLAB software.
Mrs. Parnian Mohammadi Pour, Dr. Seyed Mohsen Seyed Mosavi ,
Volume 10, Issue 3 (12-2021)
Abstract
Security Constrained Unit Commitment is a practical way for the system operator to plan and operate in real time. Considering the transmission system and security constraints can lead to different responses to load distribution. One of the solutions to solve problems in the circuit of units with large-scale security constraints is to use the Benders analysis method. But strengthening the way the problem is written puts a big difference on the speed of solution and the computational volume the purpose of this research is existing N-K constraint might lead possibility to ignore some other constraints and minimize the calculation. In the proposed model, studied faults are identified in a loop, and power flow control are proceeded by adding necessary constraints. In each step, transmission system constrains are defined, and in case any overloading occurs, relating constrain is going to be activated in the following step. This strategy defines necessary constraints in each hour and line. Also, sensitive network lines which are overloaded due to lines subjected to fault exit could be defined. Considering the mentioned issues, the importance of Unit Commitment and optimal solution proposition in large scale, in the thesis we are going to analyze the unit commitment by using line outage distribution factor and its combination with N-K security constraint. The calculation volume in large scale could be decreased by applying this strategy, thus, the computation is fast-speed. On the other hand, all the computations and comparisons are applied on IEEE 118-bus network using GAMS software and MATPOWER tool to analyze power distribution factors. A repeating constraint identification loop is employed to implement N-K constraint, and results show the loop reduces the computation time. In the proposed method, the sensitive lines and their operation conditions are identified that the appropriate response can be achieved in the fault conditions.
Jalil Jalili, Dr. Sayyed Mohammad Mehdi Mirtalaei, Dr. , Mohammad Reza Mohammadi , Dr. Behrooz Majidi,
Volume 11, Issue 4 (3-2023)
Abstract
In this paper, a non-isolated current-fed high step-up switching converter, is presented. In proposed converter are used of coupled-inductor and bootstrap capacitor. Input current proposed converter is continuous and compared to its high step-up counterpart has less ripple input current. With low coupled-inductor RMS current in the proposed, used of copper losses and smaller ferrite core. Also, due to common ground, common mode current is decreased. In this paper, the operational principle and characteristics of proposed converter are presented, and in order to verify the proposed converter, a 20-400V, 200W prototype converter is implemented and experimental results are provided.
Shahryar Shirdel, Dr. Mazdak Teimoortashloo, Dr. Mohammad Mohammadiun, Dr. Abdorreza Alavi Gharahbagh,
Volume 12, Issue 2 (9-2023)
Abstract
Due to the widespread use of electric motors in various industries, checking the conditions and diagnosing its possible faults in the early stages is one of the most important goals of intelligent industrial monitoring equipment in modern factories. Bearings are one of the mechanical parts that often fail during operation. The mechanical faults of the electric motor show themselves as vibration in the motor, which can be used to diagnose the fault, especially in the early stages. In addition, noise in industrial environments usually has less impact on vibration because vibration is extracted directly from the motor body or its base. According to this explanation, in this research, a bearing fault detection method is proposed using wavelet transform of the vibration signal in induction motors, which can detect the defect with very high accuracy. The proposed method was implemented on two different databases using Matlab 2021. The obtained results, compared with the latest articles in this field, confirmed the effectiveness of proposed method based on criteria such as accuracy and correctness. In the meantime, the advantages of proposed method, such as high speed, low calculations and its robustness to noise, were also shown.
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