A GridConnected SinglePhase PV Microinverter With Very Low DC Bus Capacitance, Low THD, and Improved Transient Response
F
Bahraini
M.Sc. Student in the School of Electrical Engineering, Iran University of Science & Technoloy (IUST), Tehran, Iran
author
Adib
Abrishamifar
Associate Professor in the School of Electrical Engineering, Iran University of Science & Technology (IUST), Tehran, Iran
author
A
Rahmati
Associate Professor in the School of Electrical Engineering, Iran University of Science & Technology (IUST), Tehran, Iran
author
text
article
2019
per
Nowadays microinverter with power levels ranging from 150 to 300 W, has become the trend for some gridconnected PV systems specially for residential PV systems. Also, in marine industries, photovoltaic microinverters can be used to produce a part of the electrical energy required on ships. In single phase microinverters there is a doublefrequency ripple on the DC bus voltage that causes harmonics and reduces power factor. In order to reduce this ripple, large electrolytic capacitors are often used at the DC bus that the drawback is short lifetime of these capacitors. To overcome this problem, it is necessary to replace electrolytic capacitors with thin film capacitors that have long life and low capacitance. By decreasing the capacitance the amplitude of double frequency ripple on the bus voltage increases so the common bus voltage controller (PI) can’t solve the tradeoff between the output current THD and bus voltage fluctuations (overshoot and undershoot). In this paper, by using the proposed control methods a microinverter is designed and simulated so that this tradeoff has been solved without using additional hardware. This microinverter is connected to the grid (220V, 50Hz). It has a very small 20µF bus capacitor. The bus voltage has negligible overshoot and undershoot in response to a 200W input power step. THD of the injected current to the grid is 0.44% at 250W output power. The effectiveness of the proposed method is validated by simulation results in MatlabSimulink software.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
1
15
http://ijmt.iranjournals.ir/article_33466_728c95a99b07dc3e67a6d98216a9d0ae.pdf
Implementation of Image Processing Algorithm on Efficient Embedded Systems with Open Source Development Tools
M.R
Mousavi
استاد دانشکده مهندسی برق دانشگاه علم و صنعت ایران
author
B.
Mohammadi
دانشجوی کارشناسی ارشد  دانشکده مهندسی برق، دانشگاه علم و صنعت ایران
author
M.
Nasiri
استادیار  دانشکده فناوری اطلاعات و ارتباطات، دانشگاه جامع امام حسین (ع)
author
text
article
2019
per
In many practical applications, implementation of algorithms is required into lowcost and lowpower hardware, proper processing power, simplicity in algorithm development and maximum flexibility. Proper implementation of these methods and realtime operations for defense systems has particular importance. Studies have shown that Raspberry Pi 2 has sufficient computational power to implement an infrared target detection algorithm. Therefore, in this paper, Raspberry Pi 2 is considered as lowcost, lowweight, and lowpower hardware for optimum implementing infrared target detection methods and to optimize and reduce runtime, it with the overclocking technique is used. Finally, their performance is compared with other hardware with different software development environment. These comparisons include the Qt software development environment based on the OpenCV image processing library in the Raspberry Pi 2 hardware with Qt software development environment based on the OpenCV library functions in the PC hardware, as well as the highlevel MATLAB software. The results show that implementation on the Raspberry Pi 2 in comparison with MATLAB speeds up implementation of the algorithm 6.5 times. As well as, implementation time of the infrared target detection algorithm (C ++) using the OpenCV library on the PC is approximately eight times that of Raspberry Pi 2. Also, comparing Raspberry Pi 2 and PC in terms of power consumption, weight and cost is observed that Raspberry Pi 2 has a much better performance in terms of power consumption, weight and cost than PCs. The results show that although the use of highlevel software such as MATLAB has background suppression factor (SCR) and signal to clutter ratio (BSF) higher than use of the OpenCV library, the results of runtime indicate that the proposed hardware improves the runtime of highlevel software like MATLAB. The results of optimization on the Raspberry Pi 2 show that speed of the algorithm is improved by more than 40%.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
16
30
http://ijmt.iranjournals.ir/article_33321_6a9a98bc7f7cdd3076442e0dc18bd3c4.pdf
Coral Reef modeling using Support Vector Regression and applying spectral indices
S
eslami
دانشجوی ارشد مهندسی عمران دانشگاه تهران
author
M
hasanlou
استادیار دانشکده مهندسی نقشه برداری دانشگاه تهران
author
text
article
2019
per
Coral reef communities face unprecedented pressures at local, regional and global scales as a consequence of climate change and anthropogenic disturbance. Remote sensing, from satellites or aircraft, is possibly the only means to measure the effects of such stresses at appropriately large spatial scales. Coral reefs are indicators of environmental, climate and sea surface change which shows the reefs damages. For this purpose, an algorithm that includes relation between those variables was used. Australia’s Heron reef island is considered to be studied. In order to modeling the coral reef health condition by support vector regression (SVR), water and coral important spectral indexes and features was found using landsat8. From this method, the SVR is achieved the high performance for modeling the statistical problem .In this study we used genetic algorithm (GA) and sequential feature selection (SFS) for selecting suitable features in order to estimate model. The results for the testing data in this area of best model is [RMSE= 0.53 and R² =0.983] that show the high SVR performance.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
31
44
http://ijmt.iranjournals.ir/article_32730_d8754f0cf6c5e90fe7949c87f4f3ebe9.pdf
speed control of Induction motor using Predictive Torque Control Method
A
Goldani
کارشناس ارشد مهندسی برق دانشگاه علوم دریایی امام خمینی(ره)
author
A
ramezani varkani
iut
author
text
article
2019
per
Model predictive controllers rely on dynamic model of the process, most often linear models obtained by system identification. The advantage of MPC is the fact that it allows the current timeslot to be optimized by keeping future timeslots in account. In this paper, the transient performance of MPC method against DTC with non linear Hysteresis based controllers is presented. Then a comparative performance in terms of torque and flux ripple are presented for PTC and DTC of three phase induction motor drive. In predictive control the control objectives are defined as cost function, which is to be minimized to have a greater flexibility to include constraints which results in low computational complexity compared to DTC scheme. simulation results of PTC and DTC in MATLAB/ SIMULINK are shown and compared. This comparison between is carried out by validating the feasibility of PTC and highlighting some important implementation issues.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
45
52
http://ijmt.iranjournals.ir/article_31980_84d970f83598cc60814781ab3d390c19.pdf
A survey on design methodology and performance analysis of a marine engine mount
A
Mehrkish
Mechanical engineering department, Ferdowsi University of Mashhad, Iran.
author
A.A
Akbari
Ferdowsi University of Mashhad
author
text
article
2019
per
The main responsibility of an engine mount as a component which attaches the engine to chassis is control and absorption of different resources of vibration. Design process of marine engine mounts is one of main issues in the recent years in marine industries. Hence, a deep study in diverse design methodologies and performance analysis would be necessary to suggest an appropriate process for engine mount design. This study based on researches on design methods, suggest design and selection algorithm for marine engine mounts in four steps: primarily design, conceptual design, detail design, and finally performance assessment. Afterwards, the suggested process will imply for an internal marine engine mount with 200 hp. Based on achieved results, the final designed engine mount for this case in critical situation will have safety factor of 2.1 in static analysis and it also have a desired distance from excited frequency in frequency analysis. Finally, dynamic modeling results for this engine mount will be presented based on designed GUI by research team.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
53
66
http://ijmt.iranjournals.ir/article_32756_1c03fec28400552c2bbd7200494905fb.pdf
Energy analysis and optimization of wind turbines by Ant colony optimization algorithm in efficiency and power output
R
Yazdanparast
Department Of Mechanical Engineering, Nour Azad University, Nour, Iran.
author
N
Kordani
استادیار مهندسی مکانیک، دانشکده مهندسی، دانشگاه مازندران
author
text
article
2019
per
A theorical method is presented to analyse a way to increase generated power and energy efficiency in wind turbine by optimizing the Cutin, Rated, Furling speeds by the ant colony algorithm. In this paper, we first discuss the wind turbine math modeling, which ultimately achieves the objective function. Then, by collecting the turbine statistical data, the computerized code of the neural network, wind turbine is modeled in MATLAB software and its results are presented as tables and diagrams. By examining the results of optimization by ant colony algorithm and comparing the data with the results of the research in the article on exergy analysis of wind turbines and Also the paper that describes the exergy analysis and optimization of wind turbines by genetic algorithm and searching algorithm optimizing the turbine, Finally, 65.63% increase in output power and 61.54% increase in energy efficiency was observed in the ant algorithm.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
67
77
http://ijmt.iranjournals.ir/article_31668_ac39a082b863d44ee1fedda6423b1051.pdf
Evaluation of Pile Geometric Characteristics Effect on Pile Breakwater Performance under Sea Waves Loading via Physical Models and Numerical Solution
m
shokatian
university of tabriz
author
alireza
mojtahedi
university oftabriz
author
H
Ahmadi
university of tabriz
author
text
article
2019
per
Pile breakwaters are the type of slotted breakwaters that decrease the wave effect on coastal areas but do not entirely stop the wave activity by transmitting just a certain ratio of the wave energy. Pile breakwaters have less environmental consequences than the conventional type of breakwaters (Rubble mound breakwaters). In this study, the numerical simulations of pile breakwater and wave interaction are carried out by Computational Fluid Dynamics (CFD) methods and compared and validated with gathered laboratory data. In this paper, a model of pile breakwaters with nine piles imposed on regular and irregular wave attack is simulated and investigated via using CFD software. The main goal of this paper is to investigate the effect of piles shape and orientation on the wave reflection coefficient. According to proposed equations for wave reflection coefficient of the mono pile with square cross section and various Orientation against wave, the angle of attack waves is evaluated in order to improve the efficiency and performance of the pile breakwaters. Based on the reflection coefficient equations proposed in this paper, the angles ψ=12° and ζ=10° or ψ=17° and ζ=15° of piles against wave are proposed as the optimum angles. Results demonstrate the piles with square cross section which are in optimum condition have maximum 33 percent and at least 7 percent larger reflection than other conditions in the considered pile breakwater model.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
78
91
http://ijmt.iranjournals.ir/article_33749_f20b879cac91ae8c704a483e8b094b67.pdf

H
Ahmadi
استادیار، دانشکده فنی مهندسی عمران، دانشگاه تبریز
author
M
Bayrami
کارشناسی ارشد، دانشکده فنی مهندسی عمران، دانشگاه تبریز
author
M.A
Lotfollahi
استاد، دانشکده فنی مهندسی عمران، دانشگاه تبریز
author
text
article
2019
per
                                                                                                                                                   
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
92
107
http://ijmt.iranjournals.ir/article_33613_748feda9c80d90737a4aafc0c3d90a7b.pdf
Investigating Seismic Response of PileSupported Wharf under the Effect of Loading and Unloading Cranes
Sh
Shaaker Ardakani
Civil Engineering School, Engineering Department, University of Qom, Qom, Iran
author
R
Amirabadi
Civil Engineering School, Engineering Department, University of Qom, Qom, Iran
author
H
HeidaryTorkamani
Lecturer, Faculty of Engineering, School of Civil Engineering, University of Qom, Qom, Iran
author
text
article
2019
per
Many researchers have investigated seismic performance of pile supported wharfs, but few studies are conducted to examine the effect of loading and unloading cranes on seismic responses of this type of wharfs. This was due to an expired belief which considers the crane as a damper for the structure beneath and reduces the seismic responses of the wharf. Since, ignoring the crane would enhance the safety factor of the design. This research aims to find the impact of crane on seismic responses of a pile supported wharf. Hence, a common type of pile supported wharf by specified geotechnical and structural parameters used in Persian Gulf ports with and without crane is 3D modeled in SAP2000. Assessment of the seismic responses of the wharf is done via an incremental dynamic analysis. Finally, by using the destruction criterions which are adapted from pushover analysis, fragility curves of the wharf are proposed in three different moods. Analyzing and observing the resulting values and curves show that a crane does not affect the seismic and vulnerability responses of the wharf in the direction parallel to the seashore however, in the direction perpendicular to the seashore, despite of the reduction of the wharf seismic responses the vulnerability responses increase.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
108
119
http://ijmt.iranjournals.ir/article_32889_7e45da452d62306540739f5023f94271.pdf
A Modified Grey Wolf Optimizer by Individual Best Memory and Penalty Factor for Sonar and Radar Dataset Classification
M
Taghavi
Department of Electronics and Computers, Noshirvani Institute of Technology, Babol
author
Mohammad
Khishe
Electronic Departemant, Imam Khomeini Marine University
author
text
article
2019
per
Metaheuristic Algorithms (MA) are widely accepted as excellent ways to solve a variety of optimization problems in recent decades. Grey Wolf Optimization (GWO) is a novel Metaheuristic Algorithm (MA) that has been generated a great deal of research interest due to its advantages such as simple implementation and powerful exploitation. This study proposes a novel GWObased MA and two extra features called Individual Best Memory (IBM) and Penalty Factor (PF) to train Feedforward Neural Network (FNN) for the classification of Sonar and Radar datasets. Besides, FNN is accompanied by Feature Selection (FS) using GWO. Experiments were done on Sonar and Radar datasets obtained from the University of California, Irvin (UCI) to evaluate the performance of the proposed MA; the results demonstrated the proposed MA is markedly better than GWO in terms of classification accuracy, avoiding local optima stagnation, and convergence speed. This framework can be applied to naval navigation systems or atmospheric research.
فصلنامه علمی دریا فنون
دانشگاه علوم دریایی امام خمینی (ره) نوشهر
24236853
6
v.
1
no.
2019
120
130
http://ijmt.iranjournals.ir/article_35433_5cdcb066df252964589b869177d1113e.pdf