Showing 14 results for Photovoltaic
M. A. S. Masoum, M. Sarvi,
Volume 1, Issue 1 (1-2005)
Abstract
A new fuzzy maximum power point tracker (MPPT) for photovoltaic systems is
proposed. Fuzzy controller input parameters dI dP , ) dI dP ( D and variation of duty cycle
( DC D ) are used to generate the optimal MPPT converter duty cycle, such that solar panel
maximum power is generated under different operating conditions. A photovoltaic system
including a solar panel, a fuzzy MPP tracker and a resistive load is designed, simulated and
constructed. The fuzzy MPP tracker includes a buck dc/dc converter, fuzzy controller and
interfacing circuits. Theoretical and experimental results are used to indicate the advantages
and limitations of the proposed technique.
R. Noroozian, M. Abedi, G. B. Gharehpetian, S. H. Hosseini,
Volume 3, Issue 3 (7-2007)
Abstract
This paper describes a DC isolated network which is fed with Distributed
Generation (DG) from photovoltaic (PV) renewable sources for supplying unbalanced AC
loads. The battery energy storage bank has been connected to the DC network via DC/DC
converter to control the voltage of the network and optimize the operation of the PV
generation units. The PV arrays are connected to the DC network via its own DC/DC
converter to ensure the required power flow. The unbalanced AC loads are connected to the
DC network via its own DC/AC converter. This paper proposes a novel control strategy for
storage converter which has a DC voltage droop regulator. Also a novel control system
based on Park rotating frame has been proposed for DC/AC converters. In this paper, the
proposed operation method is demonstrated by simulation of power transfer between PV
arrays, unbalanced AC loads and battery unit. The simulation results based on
PSCAD/EMTDC software show that DC isolated distribution system including PV
generation systems can provide the high power quality to supplying unbalanced AC loads.
A. Hajizadeh,
Volume 9, Issue 1 (3-2013)
Abstract
This paper presents modeling and control of a hybrid distributed energy sources including photovoltaic (PV), fuel cell (FC) and battery energy storage (BES) in a microgrid which provides both real and reactive power to support an unbalanced utility grid. The overall configuration of the microgrid including dynamic models for the PV, FC, BES and its power electronic interfacing are briefly described. Then controller design methodologies for the power conditioning units to control the power flow from the hybrid power plant to the unbalanced utility grid are presented. In order to distribute the power between power sources, the neuro-fuzzy power controller has been developed. Simulation results are presented to demonstrate the effectiveness and capability of proposed control strategy.
J. Ghazanfari, M. Maghfoori Farsangi,
Volume 9, Issue 3 (9-2013)
Abstract
In this paper, a robust Maximum Power Point Tracking (MPPT) for PV array has been proposed using sliding mode control by defining a new formulation for sliding surface which is based on increment conductance (INC) method. The stability and robustness of the proposed controller are investigated to load variations and environment changes. Three different types of DC-DC converter are used in Maximum Power Point (MPP) system and the results obtained are given. The simulation results confirm the effectiveness of the proposed method in the presence of load variations and environment changes for different types of DC-DC converter topologies.
A. Gharaveisi, G. A. Heydari, Z. Yousofi,
Volume 10, Issue 3 (9-2014)
Abstract
In this paper, the Vector Based Swarm Optimization method is used for designing an optimal controller for the maximum power point tracker of a stand-alone PV System. The proposed algorithm is executed on vectors in a multi-dimension vector space. These vectors by appropriated orientation converge to a global optimum while the algorithm runs. The Remarkable point of the VBSO algorithm is how using completely random coefficients have good influence on algorithm performance. The generated energy is delivered to a boost converter including a resistive load. The duty cycle of the converter’s switch is determined in order to minimize generated power deviation, relative to PV voltage.
F. Hasanzad, H. Rastegar, G. B. Gharehpetian, M. Pichan,
Volume 13, Issue 2 (6-2017)
Abstract
Photovoltaic systems integrated to the grid have received considerable attention around the world. They can be connected to the electrical grid via galvanic isolation (transformer) or without it (transformerless). Despite making galvanic isolation, low frequency transformer increases size, cost and losses. On the other hand, transformerless PV systems increase the leakage current (common-mode current, (CMC)) through the parasitic capacitors of the PV array. Inverter topology and switching technique are the most important parameters the leakage current depends on. As there is no need to extra hardware for switching scheme modification, it's an economical method for reducing leakage current. This paper evaluates the effect of different space vector modulation techniques on leakage current for a two-level three-phase four-leg inverter used in PV system. It proposes an efficient space vector modulation method which decreases the leakage current to below the quantity specified in VDE-0126-1-1 standard. furthermore, some other characteristics of the space vector modulation schemes that have not been significantly discussed for four-leg inverter, are considered, such as, modulation index, switching actions per period, common-mode voltage (CMV), and total harmonic distortion (THD). An extend software simulation using MATLAB/Simulink is performed to verify the effectiveness of the modulation technique.
M. Ghani Varzaneh, A. Rajaei, M. Fakhraei,
Volume 13, Issue 3 (9-2017)
Abstract
This paper presents a new structure to provide the ability for power sharing of two Z-source inverters. According to the operation principles of Z-source inverters, only one input source supplies the circuit, which is a limitation particularly for the stand alone systems feeded by limited output power such as photovoltaics and feul cells. Furthermore; if one source fails to supply, the load can't be supplied. This paper covers those via interconnection of impedance network of two Z-source inverters. The operating principles of the proposed topology for the stand-alone and power sharing conditions are described and the relations are derived. The topology is simulated, which the results verify the theoretical analysis and well performance of the system.
A. Azghandi, S. M. Barakati, B. Wu,
Volume 14, Issue 4 (12-2018)
Abstract
A voltage source inverter (VSI) is widely used as an interface for distributed generation (DG) systems. However, high-power applications with increasing voltage levels require an extra power converter to reduce costs and complications. Thus, a current source inverter (CSI) is used. This study presents a precise phasor modeling and control details for a VSI-based system for DG and compares it with a CSI-based system. First, the dynamic characteristics of the system based on amplitude-phase transformation are investigated via small signal analysis in the synchronous reference frame. Moreover, the performance of the grid-connected system is determined by adopting the closed-loop control method based on the obtained dynamic model. The control strategies employ an outer active-power loop cascaded with an inner reactive-power loop, which the inner loop is a single-input single-output system without coupling terms. The sensitivity analysis of the linearized model indicates the dynamic features of the system. The simulation results for the different conditions confirm proposed model and design of the controller.
S. M. Hoseini, N. Vasegh, A. Zangeneh,
Volume 16, Issue 2 (6-2020)
Abstract
In this paper, a robust local controller has been designed to balance the power for distributed energy resources (DERs) in an islanded microgrid. Three different DER types are considered in this study; photovoltaic systems, battery energy storage systems, and synchronous generators. Since DER dynamics are nonlinear and uncertain, which may destabilize the power system or decrease the performance, distributed robust nonlinear controllers are designed for the DERs. They are based on the Lyapunov stabilization theory and super-twisting integral sliding mode control which guarantees system stability and optimality simultaneously. The reference signals for each DER are generated by a supervisory controller as a power management system. The controllers proposed in this work are robust, have fast response times, and most importantly, the control signals satisfy physical system constraints. The designed controller stability and effectiveness are also verified using numerical simulations.
N. Danapour, E. Akbari, M. Tarafdar-Hagh,
Volume 18, Issue 3 (9-2022)
Abstract
In electricity generation through photovoltaic cells, efficient inverters are required to inject the generated power into the grid. Among the inverters connected to the grid, current source inverters despite their advantages are used less than voltage source ones. Different circuits are presented for these converters. In this paper, several power circuit topologies of the current source inverters, which are an interface between solar panels and the grid, are reviewed. Also, the inverters are compared from the point of some indexes like efficiency, voltage transmission ratio, total harmonic distortion, leakage currents, and their reduction methods. The importance of these indexes is investigated too. Categorization is for full-bridge inverters and special structures groups. The first group includes the conventional inverter, 4-leg inverter, CH7 CSI, H7 CSI, three-mode, and other structures. The second group consists of inverters with special structures and is independent of the conventional CSI. The summary of the studies is presented in a table.
Vahid Bagheri, Amir Farhad Ehyaei, Mohammad Haeri,
Volume 18, Issue 4 (12-2022)
Abstract
In distribution networks, failure to smooth the load curve leads to voltage drop and power quality loss. In this regard, electric vehicle batteries can be used to smooth the load curve. However, to persuade vehicle owners to share their vehicle batteries, we must also consider the owners' profits. A challenging problem is that existing methods do not take into account the vehicle owner demands including initial and final states of charge and arrival and departure times of vehicles. Another problem is that battery capacity of each vehicle varies depending on the type of vehicle; which leads to uncertainties in the charging and discharging dynamics of batteries. In this paper, we propose a modified mean-field method so that the load curve is smoothed, vehicle owner demands are met, and different capacities of electric vehicle batteries are considered. The simulation results show the effectiveness of the proposed method.
A. O. Issa, A. I. Abdullateef, A. Sulaiman, A. Y. Issa, M. J. E. Salami, M. A. Onasanya ,
Volume 19, Issue 3 (9-2023)
Abstract
Grid-connected photovoltaic (PV) system is often needed whenever utilities fail to provide consumers with a reliable, sufficient and quality power supply. It provides more effective utilization of power, however, there are technical requirements to ensure the safety of the PV installation and utility grid reliability. In solar systems there is often excessive use of components, resulting in high installation costs. Consequently, appropriate measures must be taken to develop a cost-effective grid-connected PV system. An optimally sized PV system incorporated into an existing unreliable grid-connected commercial load for Mount Olive food processing is presented in this paper. The study focused on providing a reliable electricity supply which is cost-effective and environment-friendly. The techno-economic analysis of grid-connected PV/Diesel/Battery Storage systems was carried out using HOMER Pro software. Results showed that Grid/PV/BSS are technically, economically and environmentally feasible with the cost of energy at 0.136$/kWh and net present cost at $254,469. Also, the excess electricity produced by this combination is 13,264kWh/year, which generates income for the company by selling excess generated energy back to the grid if net metering were to be implemented. Furthermore, the CO2 emissions for these combinations decreased to 10,081.6 kg/year as compared to the existing systems (Grid/Diesel Generator) with emissions of 124,480 kg/year. This is an additional advantage in that it improves the greenhouse effect. A sensitivity analysis was carried out on the variation of load change, grid power price and schedule outages for the optimal system.
Mon Prakash Upadhyay, Arjun Deo, Ajitanshu Vedratnam ,
Volume 20, Issue 0 (12-2024)
Abstract
This paper provides an overview of the current innovations in Building Integrated Photovoltaic Thermal Systems. This paper briefly describes varying performance evaluation techniques, optimisation techniques, and the environmental impact and cost implication of Building Integrated Photovoltaic Thermal systems. The results reveal high energy-pin efficiency with Building Integrated Photovoltaic Thermal systems of over 50% and more efficient than when the two systems are incorporated separately. Exergy analysis is a more insightful means of analysing system effectiveness than energy analysis. The paper covers the current algorithms for various optimisation, algorithms such as Genetic Algorithms and Particle Swarm Optimisation, that provide enhanced utilisation improvements. An evaluation of the environmental impact of Building Integrated Photovoltaic Thermal in terms of carbon dioxide emission reduction and building energy optimisation is made. The results of the life cycle cost studies show that, even though the initial cost is higher than conventional solutions, the overall economic profit is more significant in the future. Some of the challenges described in the paper include increased initial costs and sophisticated integration procedures. In contrast, possible future developments include new materials, Building Integrated Photovoltaic Thermal system standardisation, and integration in smart grids. This review is intended to be a state-of-the-art source of information for researchers, engineers, architects, and policymakers involved in enhancing sustainable building technologies using building-integrated photovoltaic thermal systems.
Aboubakeur Hadjaissa, Mohammed Benmiloud, Khaled Ameur, Halima Bouchenak, Maria Dimeh,
Volume 20, Issue 0 (12-2024)
Abstract
As solar photovoltaic power generation becomes increasingly widespread, the need for photovoltaic emulators (PVEs) for testing and comparing control strategies, such as Maximum Power Point Tracking (MPPT), is growing. PVEs allow for consistent testing by accurately simulating the behavior of PV panels, free from external influences like irradiance and temperature variations. This study focuses on developing a PVE model using deep learning techniques, specifically a Multi-Layer Perceptron (MLP) Artificial Neural Network (ANN) with backpropagation as the learning algorithm. The ANN is integrated with a DC-DC push-pull converter controlled via a Linear Quadratic Regulator (LQR) strategy. The ANN emulates the nonlinear characteristics of PV panels, generating precise reference currents. Additionally, the use of a single voltage sensor paired with a current observer enhances control signal accuracy and reduces the PVE system's hardware requirements. Comparative analysis demonstrates that the proposed LQR-based controller significantly outperforms conventional PID controllers in both steady-state error and response time.
