scholarly journals Design a New DC-DC Converter for a Grid Connected Photovoltaic System

2021 ◽  
Vol 23 (1) ◽  
pp. 79-86
Author(s):  
Hassen Kaddour ◽  
Abderrahmane Dib
Keyword(s):  
Optimal Control ◽  
Control System ◽  
Power Factor ◽  
High Performance ◽  
Large Scale ◽  
Reactive Power ◽  
Boost Converter ◽  
Photovoltaic System ◽  
Optimal Switching ◽  
Svm Model

This paper presents a recent technique for photovoltaic grid connected systems based on the use of the (DPC-SVM) to select the optimal switching states to apply to the inverter, where the extended reactive power is used instead of reactive power. This technique allows achieving an optimal control of the inverter which manifests in controlling the converters using an MPPT algorithm instead of controlling each part separately. This yields to a reduced global control system on a large scale. In this context, we suggest a DC-DC boost converter circuit to ensure better behavior of the system. The FMV technique is used to inject specific harmonics in order to eliminate or minimize the undesired harmonics. The SVM model has also been developed for optimal control of the inverter to prove the high performance of the proposed method. All the results are analyzed theoretically. The simulation has shown that this strategy gives satisfactory performances, improvement of the power factor and a reduction of the THD by 37%.

scholarly journals Voltage Rise Regulation with a Grid Connected Solar Photovoltaic System

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7510
Author(s):  
Akinyemi Ayodeji Stephen ◽  
Kabeya Musasa ◽  
Innocent Ewean Davidson
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Photovoltaic System ◽  
Voltage Amplitude ◽  
Phase Voltage ◽  
Unity Power Factor ◽  
Voltage Rise ◽  
Grid Current

Renewable Distributed Generation (RDG), when connected to a Distribution Network (DN), suffers from power quality issues because of the distorted currents drawn from the loads connected to the network over generation of active power injection at the Point of Common Coupling (PCC). This research paper presents the voltage rise regulation strategy at the PCC to enhance power quality and continuous operation of RDG, such as Photovoltaic Arrays (PVAs) connected to a DN. If the PCC voltage is not regulated, the penetration levels of the renewable energy integration to a DN will be limited or may be ultimately disconnected in the case of a voltage rise issue. The network is maintained in both unity power factor and voltage regulation mode, depending on the condition of the voltage fluctuation occurrences at the PCC. The research investigation shows that variation in the consumer’s loads (reduction) causes an increase in the power generated from the PVA, resulting in an increase in the grid current amplitude, reduction in the voltage of the feeder impedance and an increase in the phase voltage amplitude at the PCC. When the system is undergoing unity power factor mode, PCC voltage amplitude tends to rises with the loads. Its phase voltage amplitude rises above an acceptable range with no-loads which are not in agreement, as specified in the IEEE-1547 and Southern Africa grid code prerequisite. Incremental Conduction with Integral Regulator bases (IC + PI) are employed to access and regulate PVA generation, while the unwanted grid current distortions are attenuated from the network using an in-loop second order integral filtering circuit algorithm. Hence, the voltage rise at the PCC is mitigated through the generation of positive reactive power to the grid from the Distribution Static Compensator (DSTATCOM), thereby regulating the phase voltage. The simulation study is carried out in a MATLAB/Simulink environment for PVA performance.

scholarly journals A DQ Synchronous Reference Frame Current Control for Grid Connected Photovoltaic Systems usingSingle Phase Cascaded H Bridge Multilevel Inverter

2019 ◽  
Vol 8 (4) ◽  
pp. 2814-2822
Keyword(s):  
Reference Frame ◽  
High Performance ◽  
Single Phase ◽  
Reactive Power ◽  
Current Control ◽  
Photovoltaic System ◽  
Real Component ◽  
Phase Inverter ◽  
Synchronous Reference Frame ◽  
Single Phase Inverter

This paper projects a high performance decoupled current control using a dq synchronous reference frame for single-phase inverter. For the three-phase inverter the conversion from AC to DC with Proportional Integral controller grants to obtain steady state error for AC Voltages and currents but has a few challenges with the single-phase systems. Hence, an orthogonal pair (β) is created by shifting the phase by one quarter cycle with respect to the real component (α) which is needed for the transformation from stationary to rotating frame. The synchronous reference frame control theory helps in controlling the AC voltage by using DC signal as the reference with the proportional integrator controllers. The implementation of the control is done with two-stage converter with LCL filter for a single-phase photovoltaic system. A modified MPPT Incremental conductance algorithm along with decoupled current control helps in regulating the active and reactive power infused into the grid where the power factor is improved, the efficiency of the system is increased above 95% and total harmonic distortion for current is also reduced to3%. The results have been validated using MATLAB.

scholarly journals Power factor control of PV generators in local distribution networks using fuzzy logic concept

2018 ◽  
Vol 7 (2.28) ◽  
pp. 362
Author(s):  
Raed A. Shalwala
Keyword(s):  
Fuzzy Logic ◽  
Control System ◽  
Power Factor ◽  
Fuzzy Logic Control ◽  
Reactive Power ◽  
Distribution Network ◽  
Voltage Control ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Logic Control

One of the most important operational requirements for any electrical power network for both distribution and transmission level is voltage control. Many studies have been carried out to improve or develop new voltage control techniques to facilitate safe connection of distributed generation. In Saudi Arabia, due to environmental, economic and development perspectives, a wide integration of photovoltaic (PV) genera-tion in distribution network is expected in the near future. This development in the network may cause voltage regulation problems due to the interaction with the existing conventional control system. In a previous paper, a control system has been described using a fuzzy logic control to set the on-line tap changer for the primary substation. In this paper a new control system is proposed for controlling the power factor of individual PV invertors based on observed correlation between net active and reactive power at each connection. A fuzzy logic control has been designed to alter the power factor for the remote invertors from the secondary substation to keep the feeder voltage within the permissible limits. In order to confirm the validity of the proposed method, simulations are carried out for a realistic distribution network with real data for load and solar radiation. Results showing the performance of the new control method are presented and discussed.  

Development of Air Flow Control System for Large-Scale Pre-Oxidation Furnace

2012 ◽  
Vol 542-543 ◽  
pp. 179-183
Author(s):  
Kuan Yu ◽  
Bo Zhu
Keyword(s):  
Control System ◽  
Flow Control ◽  
High Performance ◽  
Large Scale ◽  
Air Flow ◽  
Maximum Deviation ◽  
Cost Performance ◽  
Total Communication ◽  
Flow Control System ◽  
Air Flow Control

In this paper, we introduced a high cost performance design of air flow control system consisting of a programmable computer controller (PCC) and 72 inverters. PCC communicates with all the inverters using USS protocol via RS485 bus, and the real-time performance of USS communication was analyzed for this system. The commissioning and analysis show that the total communication cycle time of a subnet is less than 500ms and the maximum deviation of the inverter frequency is 0.01Hz. This system can meet the requirements of high performance carbon fiber production.

Control Method of Inverter for Large-Scale Grid-Connected Photovoltaic Generation System

2013 ◽  
Vol 448-453 ◽  
pp. 2507-2510
Author(s):  
Zhuo Zhang ◽  
Hong Wei Li
Keyword(s):  
Power Factor ◽  
Feedback Linearization ◽  
Large Scale ◽  
Reactive Power ◽  
Control Method ◽  
Solar Irradiation ◽  
Dynamic Feedback ◽  
Photovoltaic Array ◽  
Grid Connected Inverter ◽  
Photovoltaic Plant

A grid-connected inverter control method to analyze dynamic process of large-scale and grid-connected photovoltaic (PV) power station is proposed. The reference values of control variables are composed of maximum power output of the photovoltaic array in the photovoltaic power plant and power factor specified by dispatching. Control strategy of dynamic feedback linearization is adopted. Nonlinear decoupling controller is designed for realizing decoupling control of real-and reactive-power. The cascade PI regulation is proposed to avoid inaccurate parameter estimation which generates the system static error. Simulation is carried out based on the simplified power system with large-scale photovoltaic plant model, the power factor, and solar irradiation, and bus fault are considered for the further research. Its demonstrated that the parameter adjustment of PI controller is simple and convenient, dynamic response of system is transient, and the stability of the inverter control is verified.

scholarly journals Application of large-scale grid-connected solar photovoltaic system for voltage stability improvement of weak national grids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bukola Babatunde Adetokun ◽  
Joseph Olorunfemi Ojo ◽  
Christopher Maina Muriithi
Keyword(s):  
Power System ◽  
Energy Demand ◽  
Large Scale ◽  
Voltage Stability ◽  
Reactive Power ◽  
Active Power ◽  
Photovoltaic System ◽  
Critical Voltage ◽  
Solar Photovoltaic ◽  
Solar Photovoltaic System

AbstractThis paper investigates the application of large-scale solar photovoltaic (SPV) system for voltage stability improvement of weak national grids. Large-scale SPV integration has been investigated on the Nigerian power system to enhance voltage stability and as a viable alternative to the aged shunt reactors currently being used in the Nigerian national grid to mitigate overvoltage issues in Northern Nigeria. Two scenarios of increasing SPV penetration level (PL) are investigated in this work, namely, centralized large-scale SPV at the critical bus and dispersed large-scale SPV across the weak buses. The voltage stability of the system is evaluated using the active power margin (APM) also called megawatt margin (MWM) derived from Active Power–Voltage (P–V) analysis, the reactive power margin (RPM) and the associated critical voltage–reactive power ratio (CVQR) index obtained from Reactive Power–Voltage (Q–V) analysis. All simulations are carried out in DIgSILENT PowerFactory software and result analyses done with MATLAB. The results show that with centralized SPV generation for the case study system, the highest bus voltage is able to fall within acceptable limits at 26.29% (1000 MW), while the dispersed SPV achieves this at 21.44% (800 MW). Also, the dispersed SPV scenario provides better voltage stability improvement for the system as indicated by the MWM, RPM and the CVQR index of the system. Therefore, this work provides a baseline insight on the potential application of large-scale SPV in weak grids such as the Nigerian case to address the voltage stability problems in the power system while utilizing the abundant solar resource to meet the increasing energy demand.

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