scholarly journals Low voltage ride-through strategies for a 3-phase grid-connected PV system

2021 ◽  
Author(s):  
◽  
Hao Wen
Keyword(s):  
Reactive Power ◽  
Low Voltage ◽  
Pv System ◽  
Low Voltage Ride Through ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Voltage Compensation ◽  
Sinusoidal Current ◽  
Power Point ◽  
Pv Generation

Grid codes is a technical specification which defines the parameters a power system that are connected to the national power systems has to ensure safe, secure and eco-nomic proper functioning of the electric system. One of these requirements is to stay connected to the grid during faults. In such scenarios, the generating unit should remain connected to the grid for a certain period and provide reactive power to support the grid. This is called low voltage ride-through capability. At the early stage, low voltage ride-through requirements were imposed for large scale generators connected to the trans-mission network. However, with the increased penetration of distributed generation, such as PV panels implemented in the distribution network, the low voltage ride-through requirements are also required for distributed generation. With the maturity of PV technology, the cost of PV generation has decreased. Therefore, the total installed capacity of grid-connected PV generation has increased; this has cre-ated new challenges to the low voltage ride-through. Power quality and transient per-formance are the most critical aspects of the grid-connected PV systems under grid faults. PV generation is permitted to switch off from the grid during a fault; however, with the high penetration of the installed PV system, it will degrade the power quality if the same method applied. It is necessary to make sure that the inverter currents remain sinusoidal and within the acceptable limits at the instant of the fault, during and after the fault clearance for different types of faults. Accordingly, this thesis proposes two low voltage ride-through strategies for a 3-phase grid-connected PV system in different reference frames. The presented low voltage ride-through control algorithm in the synchronous reference frame, which fulfils a voltage compensation unit and the reactive power injection block is designed to protect the inverter from overcurrent failure under both symmetrical and asymmetrical faults, reduce the double grid frequency oscillations and provides reac-tive power support by applying a voltage compensation unit. The inverter can also inject sinusoidal current during asymmetrical faults. The method does not require a hard switch from the Maximum Power Point Tracking to a non-Maximum Power Point Tracking algorithm, which ensures a smooth transition. The proposed method in the stationary reference frame provides a fast post-fault recov-ery, which is essential to minimize the fault impacts on the loads and the converter. The method, which consists of a new reference currents calculation block and the voltage compensation unit, maintains the converter current within acceptable limits, produces sinusoidal current even during asymmetrical faults, improves the post-fault recovery performance, and provides independent control for active and reactive powers.

Control Strategy of Photovoltaic System to Regulate Active and Reactive Power during Unbalanced Grid Voltages by Using Fuzzy Logic Control

2018 ◽  
Vol 7 (4.24) ◽  
pp. 455
Author(s):  
Gujjala Trilokya ◽  
M.Rama sekhara Reddy
Keyword(s):  
Reactive Power ◽  
Fuzzy Controller ◽  
Electronic System ◽  
Photovoltaic System ◽  
Phase Voltage ◽  
Pv System ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Set Up

The advanced reactive power regulation is planned to direct the highest and the voltages at least point of regular pairing inside the cutoff points set up in grid codes for consistent operation. These work displays a regulating technique to which the grid associated PV system meaning to direct the  power of both active and reactive infused to the electrical system amid the voltage faults that are uneven in nature. Fuzzy controller is propel controller which is for the most part appropriate for the personal fundamental guidance tool. which additionally gave the electronic system operation by the master choice. The reference of active power  is acquired from a Maximum Power Point Tracking (MPPT) calculation. The advanced force methodology creates the necessary reference currents that forced by the grid-tied inverter from the coveted P and Q powers and the deliberate voltage supply. In unequal voltage sags, positive and negative sequence KVAr are consolidated to adaptable boost and even out the phase voltages; maximum phase voltage is controlled below as far as possible and the base phase voltage simply over as far as possible. The plan is approved to a solitary step PV system where the currents that are  regulated by means of prescient control. By using the fuzzy controller for a nonlinear system which permit the decrease for the questionable impact in the system which control and impeccably enhance the effectiveness. Results demonstrating the execution of the procedure are introduced amid uneven  sags and swells.

scholarly journals Multi level Transformer less PV Inverter with Reduced Switching Losses and Elimination of CM leakage Current

2020 ◽  
Vol 9 (11) ◽  
pp. 223-228
Keyword(s):  
Leakage Current ◽  
Low Voltage ◽  
Stable Operation ◽  
Efficient Operation ◽  
Low Voltage Ride Through ◽  
Point Tracking ◽  
Pv Inverter ◽  
Switching Losses ◽  
Power Point Tracking ◽  
Power Point

In order to have efficient operation of grid connected Photovoltaic (PV) inverter, the issue of leakage current must be completely eliminated. For this new transformerless multilevel inverter is proposed in this paper with (k-1) levels in which k denotes the number of switches. The inverter provides zero common mode leakage current and also capable of operating under half of rated PV voltage, hence make this proposed inverter topology as LVRT (low voltage ride through) capable. Different modes are employed for the stable operation of the proposed inverter with varying input PV voltage. Simulation work is carried out for three, five and seven level proposed inverter topologies in MATLAB/Simulink software which determines its maximum power point tracking performance. Here the THD (Total Harmonic Distortions) of 3, 5 and 7 levels are compared.

Review on Grid Connection Technologies of DFIG

2012 ◽  
Vol 614-615 ◽  
pp. 1816-1819
Author(s):  
Xue Song Zhou ◽  
Su Yang Li ◽  
You Jie Ma
Keyword(s):  
Low Voltage ◽  
System Stability ◽  
Frequency Regulation ◽  
Low Voltage Ride Through ◽  
Point Tracking ◽  
Grid Connection ◽  
Power Point Tracking ◽  
Unbalanced Voltage ◽  
Power Point ◽  
Doubly Fed

Doubly fed induction generator (DFIG) is receiving more attention nowadays due to growing power demand and environmental concerns. In this paper, five main issues of the DFIG associating with the grid-connection, low voltage ride-through (LVRT), maximum power point tracking (MPPT) control strategy, operation in unbalanced voltage condition, contribution to frequency regulation of grid and influence on power system stability are discussed.

scholarly journals Decentralized Control of PV Inverter to Mitigate Voltage Rise in Resistive Feeder

2018 ◽  
Vol 69 ◽  
pp. 01009
Author(s):  
Tzung-Lin Lee ◽  
Shang-Hung Hu ◽  
Shih-Sian Yang
Keyword(s):  
Decentralized Control ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Measurement ◽  
Maximum Power Point ◽  
Voltage Rise ◽  
Point Tracking ◽  
Pv Inverter ◽  
Power Point Tracking ◽  
Power Point

Increasing installation of photovoltaic (PV) in the distribution power system has resulted in serious voltage rise, limiting grid-connectable power. This scenario becomes significant in the low-voltage resistive feeder. This paper proposes a decentralized control for distributed PV inverters to mitigate voltage rise. Instead of MPPT (maximum power point tracking) mode, the proposed PV inverter is able to curtail its real power and compensate the reactive power according to the impedance at the installation location. The drooped characteristics between the output power and the impedance are developed so that the PV inverters are able to cooperatively suppress voltage rise based on their local voltage measurement only. Therefore, PV inverters are allowed to supply more power to the utility within voltage limitation. Simulations are conducted to guarantee the proposed control on improvement of voltage rise considering different parameter of feeder. A lab-scaled prototype circuit is established to verify effectiveness in a resistive feeder.

scholarly journals AI based MPPT Controller for Solar PV System

2019 ◽  
Vol 9 (2S4) ◽  
pp. 592-595
Keyword(s):  
Low Voltage ◽  
Photovoltaic System ◽  
Solar Pv ◽  
Pv System ◽  
Boost Converters ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Logic Control ◽  
Solar Pv System ◽  
Power Point

This article discusses Artificial intelligence based Maximum Power Point Tracking (MPPT) for solar Photo-voltaics based system. MPPT is used to improve the efficiency as well as to raise the output through the photovoltaic system through continuous tracking of MPP. The work demands the use of fuzzy logic control technology; hence the PV-cell is interfaced with a DC step-up converter connected with a dc load. Boost converters convert the output of low voltage DC to output of high voltage DC. Following taken through the solar panel are thermal factor like temperature and isolation. The validation of the proposed controller is also discussed.

Power Tracking Control Strategy Based on Feedback Frequency of Large-Scale Grid-Connected PV Generation

2014 ◽  
Vol 986-987 ◽  
pp. 1226-1230
Author(s):  
Ling Wang ◽  
Bei Zhao ◽  
Jian Liang Zhong ◽  
Sarmad Malik ◽  
Hai Bao
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Large Scale ◽  
Pv System ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Bus Voltage ◽  
Power Point ◽  
Feedback Frequency ◽  
Pv Generation

PV (Photovoltaic) generation output with MPPT (Maximum power point tracking) is unadjustable. In this paper, PV generation is expected to regulate grid frequency. Thus a power tracking control strategy based on feedback frequency instead of MPPT is put forward. The feedback frequency is transferred to controlling unit of DC-DC inverter. The DC bus voltage is adjusted by controlling the duty cycle of DC-DC invertor. A grid-connected PV system with a power tracking control strategy based on feedback frequency and a DC-AC inverter control module are built in MATLAB-Simulink platform. Experiment result indicates that PV generation could regulate grid frequency by the control strategy based on feedback frequency.

Assessing Under Varying Circumstances the Behavior of Photovoltaic Systems of Maximum Power Point Methods.

2019 ◽  
Vol 1 (2) ◽  
pp. 45-51
Author(s):  
Imad A. Elzein ◽  
Yuri N. Petrenko
Keyword(s):  
Comparative Studies ◽  
Maximum Power Point Tracking ◽  
Maximum Power ◽  
Pv System ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
System Output ◽  
Power Point ◽  
Design Simplicity

In this article an extended literature surveying review is conducted on a set of comparative studies of maximum power point tracking (MPPT) techniques.  Different MPPT methods are conducted with an ultimate aim of how to be maximizing the PV system output power by tracking Pmax in a set of different operational circumstances. In this paper maximum power point tracking, MPPT techniques are reviewed on basis of different parameters related to the design simplicity and or complexity, implementation, hardware required, and other related aspects.

scholarly journals Maximum Power Point Tracking of PV Systems under Partial Shading Conditions Based on Opposition-Based Learning Firefly Algorithm

2021 ◽  
Vol 13 (5) ◽  
pp. 2656
Author(s):  
Ahmed G. Abo-Khalil ◽  
Walied Alharbi ◽  
Abdel-Rahman Al-Qawasmi ◽  
Mohammad Alobaid ◽  
Ibrahim M. Alarifi
Keyword(s):  
Firefly Algorithm ◽  
Maximum Power ◽  
Pv System ◽  
Maximum Power Point ◽  
Partial Shading ◽  
Point Tracking ◽  
Opposition Based Learning ◽  
Power Point Tracking ◽  
Convergence Process ◽  
Power Point

This work presents an alternative to the conventional photovoltaic maximum power point tracking (MPPT) methods, by using an opposition-based learning firefly algorithm (OFA) that improves the performance of the Photovoltaic (PV) system both in the uniform irradiance changes and in partial shading conditions. The firefly algorithm is based on fireflies’ search for food, according to which individuals emit progressively more intense glows as they approach the objective, attracting the other fireflies. Therefore, the simulation of this behavior can be conducted by solving the objective function that is directly proportional to the distance from the desired result. To implement this algorithm in case of partial shading conditions, it was necessary to adjust the Firefly Algorithm (FA) parameters to fit the MPPT application. These parameters have been extensively tested, converging satisfactorily and guaranteeing to extract the global maximum power point (GMPP) in the cases of normal and partial shading conditions analyzed. The precise adjustment of the coefficients was made possible by visualizing the movement of the particles during the convergence process, while opposition-based learning (OBL) was used with FA to accelerate the convergence process by allowing the particle to move in the opposite direction. The proposed algorithm was simulated in the closest possible way to authentic operating conditions, and variable irradiance and partial shading conditions were implemented experimentally for a 60 [W] PV system. A two-stage PV grid-connected system was designed and deployed to validate the proposed algorithm. In addition, a comparison between the performance of the Perturbation and Observation (P&O) method and the proposed method was carried out to prove the effectiveness of this method over the conventional methods in tracking the GMPP.

scholarly journals Analysis and Design of a Multi-Port DC-DC Converter for Interfacing PV Systems

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1943
Author(s):  
Bader N. Alajmi ◽  
Mostafa I. Marei ◽  
Ibrahim Abdelsalam ◽  
Mohamed F. AlHajri
Keyword(s):  
High Frequency ◽  
Computer Aided Design ◽  
Electromagnetic Transients ◽  
Pv System ◽  
Analysis And Design ◽  
Pv Systems ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point ◽  
Aided Design

A high-frequency multi-port (HFMP) direct current (DC) to DC converter is presented. The proposed HFMP is utilized to interface a photovoltaic (PV) system. The presented HFMP is compact and can perform maximum power point tracking. It consists of a high-frequency transformer with many identical input windings and one output winding. Each input winding is connected to a PV module through an H-bridge inverter, and the maximum PV power is tracked using the perturb and observe (P&O) technique. The output winding is connected to a DC bus through a rectifier. The detailed analysis and operation of the proposed HFMP DC-DC converter are presented. Extensive numerical simulations are conducted, using power system computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) software, to evaluate the operation and dynamic behavior of the proposed PV interfacing scheme. In addition, an experimental setup is built to verify the performance of the HFMP DC-DC converter.

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