4,535 research outputs found
Financial Analysis of a Grid-connected Photovoltaic System in South Florida
In this paper the performance and financial analysis of a grid-connected
photovoltaic system installed at Florida Atlantic University (FAU) is
evaluated. The power plant has the capacity of 14.8 kW and has been under
operation since August 2014. This solar PV system is composed of two 7.4 kW
sub-arrays, one fixed and one with single axis tracking. First, an overview of
the system followed by local weather characteristics in Boca Raton, Florida is
presented. In addition, monthly averaged daily solar radiation in Boca Raton as
well as system AC are calculated utilizing the PVwatts simulation calculator.
Inputs such as module and inverter specifications are applied to the System
Advisor Model (SAM) to design and optimize the system. Finally, the estimated
local load demand as well as simulation results are extracted and analyzed.Comment: 6 Pages, IEEE PVSC 2017 Conference, Washington D.
DSOGI-PLL based power control method to mitigate control errors under disturbances of grid connected hybrid renewable power systems
The control of power converter devices is
one of the main research lines in interfaced renewable
energy sources, such as solar cells and wind turbines.
Therefore, suitable control algorithms should be
designed in order to regulate power or current properly
and attain a good power quality for some disturbances,
such as voltage sag/swell, voltage unbalances and fluctuations,
long interruptions, and harmonics. Various
synchronisation techniques based control strategies
are implemented for the hybrid power system applications
under unbalanced conditions in literature studies.
In this paper, synchronisation algorithms based
Proportional-Resonant (PR) power/current controller
is applied to the hybrid power system (solar cell + wind
turbine + grid), and Dual Second Order Generalized
Integrator-Phase Locked Loop (DSOGI-PLL) based PR
controller in stationary reference frame provides a solution
to overcome these problems. The influence of
various cases, such as unbalance, and harmonic conditions,
is examined, analysed and compared to the PR
controllers based on DSOGI-PLL and SRF-PLL. The
results verify the effectiveness and correctness of the
proposed DSOGI-PLL based power control method
Design Optimization Of Llc Topology And Phase Skipping Control Of Three Phase Inverter For Pv Applications
The world is heading towards an energy crisis and desperate efforts are being made to find an alternative, reliable and clean source of energy. Solar Energy is one of the most clean and reliable source of renewable energy on earth. Conventionally, extraction of solar power for electricity generation was limited to PV farms, however lately Distributed Generation form of Solar Power has emerged in the form of residential and commercial Grid Tied Micro-Inverters. Grid Tied Micro-Inverters are costly when compared to their string type counterparts because one inverter module is required for every single or every two PV panels whereas a string type micro-inverter utilizes a single inverter module over a string of PV panels. Since in micro-inverter every panel has a dedicated inverter module, more power per panel can be extracted by performing optimal maximum power tracking over single panel rather than over an entire string of panels. Power per panel extracted by string inverters may be lower than its maximum value as few of the panels in the string may or may not be shaded and thereby forming the weaker links of the system. In order to justify the higher costs of Micro-Inverters, it is of utmost importance to convert the available power with maximum possible efficiency. Typically, a microinverter consists of two important blocks; a Front End DC-DC Converter and Output DCAC Inverter. This thesis proposes efficiency optimization techniques for both the blocks of the micro-inverter. iv Efficiency Optimization of Front End DC-DC Converter This thesis aims to optimize the efficiency of the front end stage by proposing optimal design procedure for resonant parameters of LLC Topology as a Front End DC-DC Converter for PV Applications. It exploits the I-V characteristics of a solar panel to design the resonant parameters such that resonant LLC topology operates near its resonant frequency operating point which is the highest efficiency operating point of LLC Converter. Efficiency Optimization of Output DC-AC Inverter Due to continuously variable irradiance levels of solar energy, available power for extraction is constantly varying which causes the PV Inverter operates at its peak load capacity for less than 15% of the day time. Every typical power converter suffers through poor light load efficiency performance because of the load independent losses present in a power converter. In order to improve the light load efficiency performance of Three Phase Inverters, this thesis proposes Phase Skipping Control technique for Three Phase Grid Tied Micro-Inverters. The proposed technique is a generic control technique and can be applied to any inverter topology, however, in order to establish the proof of concept this control technique has been implemented on Three Phase Half Bridge PWM Inverter and its analysis is provided. Improving light load efficiency helps to improve the CEC efficiency of the inverter
Decoupling and Control of Real and Reactive Power in Grid-Connected Photovoltaic Power System
The paper presents a detailed modeling and simulation of different control schemes of the real and reactive power flows in a three-phase voltage source inverter (VSI) interfacing a photovoltaic (PV) generation system to the power grid. Synchronisation of the inverter and grid AC waveforms is achieved using a phase-locked-loop (PLL) circuit. An effective decoupling strategy based on proportional-integral (PI) controllers is designed to eliminate the interaction between the two current components. Finally, the influence of the grid disturbances on the PV system and the influence of the solar energy intermittency on the power grid have been tested. The overall model is implemented in Matlab and Simulink/SimPowerSystems toolboxes. Simulations results with the PV system operating with real irradiance data will be presented to demonstrate the performance of the proposed decoupling and control strategies under different conditions of the power gridNon peer reviewe
Modeling a Grid-Connected PV/Battery Microgrid System with MPPT Controller
This paper focuses on performance analyzing and dynamic modeling of the
current grid-tied fixed array 6.84kW solar photovoltaic system located at
Florida Atlantic University (FAU). A battery energy storage system is designed
and applied to improve the systems stability and reliability. An overview of
the entire system and its PV module are presented. In sequel, the corresponding
I-V and P-V curves are obtained using MATLAB-Simulink package. Actual data was
collected and utilized for the modeling and simulation of the system. In
addition, a grid- connected PV/Battery system with Maximum Power Point Tracking
(MPPT) controller is modeled to analyze the system performance that has been
evaluated under two different test conditions: (1) PV power production is
higher than the load demand (2) PV generated power is less than required load.
A battery system has also been sized to provide smoothing services to this
array. The simulation results show the effective of the proposed method. This
system can be implemented in developing countries with similar weather
conditions to Florida.Comment: 6 pages, 14 figures, PVSC 201
A Novel Reduced Components Model Predictive Controlled Multilevel Inverter for Grid-Tied Applications
This paper presents an improved single-phase Multilevel Inverter (MLI) which is conceptualized to reduce power switches along with separate DC voltage sources. Compared with recent modular topologies, the proposed MLI employs a reduced number of components. The proposed inverter consists of a combination of two circuits, i.e., the level generation and polarity generation parts. The level generation part is used to synthesize different output voltage levels, while the polarity inversion is performed by a~conventional H-bridge circuit. The performance of the proposed topology has been studied using s single-phase seven-level inverter, which utilizes seven power switches and three independent DC voltage sources. Model Predictive Control (MPC) is applied to inject a sinusoidal current into the utility grid which exhibits low Total Harmonic Distortion (THD). Tests, including a~change in grid current amplitude as well as operation under variation in Power Factor (PF), have been performed to validate the good performance obtained using MPC. The effectiveness of the proposed seven-level inverter has been verified theoretically using MATLAB Simulink. In addition, Real-Time (RT) validation using the dSPACE-CP1103 has been performed to confirm the system performance and system operation using digital platforms. Simulation and RT results show improved THD at 1.23% of injected current
Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration
We show how distributed control of reactive power can serve to regulate
voltage and minimize resistive losses in a distribution circuit that includes a
significant level of photovoltaic (PV) generation. To demonstrate the
technique, we consider a radial distribution circuit with a single branch
consisting of sequentially-arranged residential-scale loads that consume both
real and reactive power. In parallel, some loads also have PV generation
capability. We postulate that the inverters associated with each PV system are
also capable of limited reactive power generation or consumption, and we seek
to find the optimal dispatch of each inverter's reactive power to both maintain
the voltage within an acceptable range and minimize the resistive losses over
the entire circuit. We assume the complex impedance of the distribution circuit
links and the instantaneous load and PV generation at each load are known. We
compare the results of the optimal dispatch with a suboptimal local scheme that
does not require any communication. On our model distribution circuit, we
illustrate the feasibility of high levels of PV penetration and a significant
(20% or higher) reduction in losses.Comment: 6 pages, 5 figures
Dynamics estimation and generalized tuning of stationary frame current controller for grid-tied power converters
The integration of AC-DC power converters to manage the connection of generation to the grid has increased exponentially over the last years. PV or wind generation plants are one of the main applications showing this trend. High power converters are increasingly installed for integrating the renewables in a larger scale. The control design for these converters becomes more challenging due to the reduced control bandwidth and increased complexity in the grid connection filter. A generalized and optimized control tuning approach for converters becomes more favored. This paper proposes an algorithm for estimating the dynamic performance of the stationary frame current controllers, and based on it a generalized and optimized tuning approach is developed. The experience-based specifications of the tuning inputs are not necessary through the tuning approach. Simulation and experimental results in different scenarios are shown to evaluate the proposal.Peer ReviewedPostprint (published version
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