Grid-connected Photovoltaic Generation System Research Articles

Novel five-level inverter based on DC power-capacitor series charge-discharge switching strategy

Photovoltaic power generation systems generally include four modules: solar cells, batteries, inverters and controllers. Among them, the inverter converts the direct current generated by the photovoltaic array into a power conversion device that meets the grid-connected requirements for industrial frequency alternating current, which is the key equipment for grid-connected photovoltaic power generation system. Most multilevel inverters in the market today are based on the Neutral-Point-Clamped (NPC) structure to generate voltages at different levels, and then control the magnitude and direction of the voltages through H-bridge circuits. This topology has been maturely used in three-level inverters, but if we want to build five-level, seven-level and more level numbers of inverters based on NPC, the number of capacitors used is increasing, and the circuit becomes more and more complex. Therefore, this paper proposes a five-level inverter topology based on single power supply-single capacitor series charging and discharging. (Power-capacitor series charge-discharge switching, PCSCDS). This inverter has a simple structure, comprehensible control strategy and requires only one DC power supply and one large capacitor to generate a five-level voltage. The topology is subsequently simulated and analyzed by MATLAB/Simulink simulation, which proves the effectiveness of the novel inverter.

Energy enhancement in grid-connected photovoltaic generation systems using adaptive control technique

This research paper presents an innovative adaptive control technique for enhancing energy efficiency in grid-connected photovoltaic (PV) generation systems. By integrating an advanced high-gain DC-DC converter with adaptive and non-linear control methods, the proposed system ensures optimal power absorption from various renewable resources and maintains robust power transfer efficiency and reliability. Key results from the implementation at the Union Territory of Puducherry substation demonstrate significant improvements: the adaptive control system dynamically adjusts to changes in source voltage and load conditions, maintaining a constant output voltage with minimized steady-state error and low overshoot. The feedback controller effectively responds to fluctuations in duty cycle and output load, ensuring stable operation under varying environmental conditions. These enhancements contribute to a reliable and efficient integration of renewable energy sources into the power grid, addressing critical challenges in renewable energy technology.

Analysis of Grid-Connected Stability of VSG-Controlled PV Plant Integrated with Energy Storage System and Optimization of Control Parameters

In the static stability analysis of the grid-connected photovoltaic (PV) generation and energy storage (ES) system, the grid-side is often simplified using an infinite busbar equivalent, which streamlines the analysis but neglects the dynamic characteristics of the grid, leading to certain inaccuracies in the results. Furthermore, the control parameter design does not consider the coupling relationships among parameters, resulting in arbitrary values and the inability to achieve overall optimality. To address these issues, this paper presents a comprehensive parameter optimization method for the oscillation characteristics of grid-connected PV generation and ES systems in various frequency ranges. Firstly, a detailed modeling of the grid-connected PV generation and ES system is conducted, resulting in the derivation of the system’s small-signal model. This study investigates the impact of parameters related to PV arrays, ES units, and the virtual synchronous generator (VSG) on the system’s characteristic roots using participation factors, sensitivity analysis, and eigenvalue root trajectories. Subsequently, based on the analysis of system root trajectories and the Particle Swarm Optimization (PSO) algorithm, a holistic parameter optimization design method for the system’s oscillation modes is proposed, and the parameter optimization results are obtained. Finally, the accuracy of the theoretical analysis is validated through perturbation testing using both Matlab/Simulink models and the small-signal model.

Asynchronous co-simulation of photovoltaic power generation system based on FPGA-CPU

In order to realize the real-time electromagnetic transient simulation of grid-connected photovoltaic power generation system with small time step, a heterogeneous multiplexed parallel real-time simulation method based on field programmable gate array (FPGA) and central processor is studied. According to the simulation accuracy requirements of the high and low frequency decoupling module, a differentiated simulation step size is used to solve the problem, and a 1us/50us FPGA-CPU multi-rate real-time simulation platform is constructed, in which the FPGA simulation part meets the real-time requirements of small-step transient simulation through the optimization of the response matching method and the EMTP algorithm, the offline simulation results are compared with Simulink, and the model before and after optimization is analyzed, the real-time electromagnetic transient simulation results are compared with Simulink, and the model before and after optimization is analyzed. By comparing the offline simulation results with Simulink and analyzing the FPGA resource consumption before and after model optimization, the accuracy and real-time performance of the co-simulation method for real-time simulation of grid-connected photovoltaic systems are verified.

Application analysis based on solar grid-connected photovoltaic power generation and intermittent energy storage system

Solar photovoltaic power generation as a building electrical professional in the energy use of important technical means, through the realisation of photovoltaic conversion, can be a large amount of light energy transmission to the building application, once the electrical energy surplus is too much, but also can be transmitted to the power grid use. Based on this, the article takes the solar photovoltaic power generation system as the basis, comprehensively analyses the operation principle and basic characteristics of solar photovoltaic power generation, summarizes the main influencing factors of grid-connected solar photovoltaic power generation, as well as the impact of grid-connected solar photovoltaic power generation on the grid, and researches on applying automation technology to solar photovoltaic power generation, such as photovoltaic buildings, DC inverters, reactive power compensation, etc., so as to comprehensively improve the grid-connected solar photovoltaic power generation efficiency and provide a constant source of energy for buildings. Solar thermal power generation technology is another kind of solar power generation technology besides photovoltaic power generation. It is a renewable energy generation method that integrates solar thermal conversion power generation, large-scale heat storage and the characteristics of power grid synchronmachine. According to the influence of different intermittent heat load fluctuation characteristics on the design of solar heat collection and heat storage system, the design method of heat collection and heat storage of intermittent solar heating system is established. The operation characteristics of solar energy system in three typical intermittent heating modes are compared and analyzed. It provides the design method and operation optimization strategy for the efficient utilization of solar heating system.

A hybrid control topology for cascaded H-bridge multilevel inverter to improve the power quality of smart grid connected system: NBO-RERNN approach

This manuscript proposes a hybrid control technique for the grid-connected photovoltaic (PV) generation system with a cascaded multilevel inverter (CMLI). The proposed hybrid approach integrates the Namib beetle optimization (NBO) and recalling-enhanced recurrent neural network (RERNN) approach, known as the NBO-RERNN technique. The cascaded multilevel inverter (MLI) is intended to increase the optimum control signal using the proposed controller. The cascaded multilevel inverter (MLI) is designed by using the minimum count of switches. The key purpose of the proposed approach is to improve power regulation or maximal solar energy conversion system (SECS) and to achieve good power quality (PQ) of the system. The proposed NBO technique generates the optimum control signal dataset offline. Based on the fulfilled dataset, the RERNN generates the best CMLI control signals inonlinemanner. The resultant control signals are used to regulate cascaded multilevel inverter insulated gate bi-polar switches (IGBT). For this purpose, the proposed NBO-RERNN control topology defines converter switching states by modeling generation system operating modes. The parameter variations of the system and external disturbances are mitigated, and the load demands are fulfilled optimally by using this control technique. The NBO-RERNN control topology is implemented in MATLAB, and its performance is compared with existing approaches. The simulation reveals that the proposed method has lower THD than the existing one.

Agricultural Grid Connected Photovoltaic System Design and Simulation in Egypt by using PVSYST Software

Agricultural Photovoltaic Systems are a key technology to achieve sustainable development goals by reducing competition between land for food and electricity. In addition, Agricultural Photovoltaic Systems are at the heart of the link between power generation, crop production and irrigation water conservation. The main ecophysiological constraint on crop production under photovoltaics is the reduction of light. It is difficult to recommend shade tolerance for some plant varieties due to insufficient information on shading conditions for most plants. The use of shading panels (photovoltaic panels) requires more crop-specific research to determine the optimal percentage of panels and their placement that will not reduce agricultural yields. Crop yield variation versus field shading and availability to maximize the system require extensive research. This study aims to develop a standard procedure for designing an agricultural grid-connected photovoltaic power generation system for solar power generation in an agricultural area in Bahteem, Egypt. The technical and annual performance of the grid-connected PV system was simulated using PV Syst software. The paper started with a pre-feasibility study of a grid-connected photovoltaic system using PV Syst. Software with an extensive database of meteorological data, including global daily horizontal solar irradiance, and a database of various renewable energy system components from different manufacturers. In this work, a comprehensive literature review of agricultural solar photovoltaic systems is conducted, with a particular focus on grid-connected systems, followed by a design procedure for grid-connected solar photovoltaic systems. The planned photovoltaic system will generate a total of 400 KWp of electricity. This generated electricity can drive down electricity prices by exporting excess electricity to the national grid. In addition, solar power systems are fuel-efficient and have a low environmental impact.

Agricultural Grid Connected Photovoltaic System Design and Simulation in Egypt by using PVSYST Software

Agricultural Photovoltaic Systems are a key technology to achieve sustainable development goals by reducing competition between land for food and electricity. In addition, Agricultural Photovoltaic Systems are at the heart of the link between power generation, crop production and irrigation water conservation. The main ecophysiological constraint on crop production under photovoltaics is the reduction of light. It is difficult to recommend shade tolerance for some plant varieties due to insufficient information on shading conditions for most plants. The use of shading panels (photovoltaic panels) requires more crop-specific research to determine the optimal percentage of panels and their placement that will not reduce agricultural yields. Crop yield variation versus field shading and availability to maximize the system require extensive research. This study aims to develop a standard procedure for designing an agricultural grid-connected photovoltaic power generation system for solar power generation in an agricultural area in Bahteem, Egypt. The technical and annual performance of the grid-connected PV system was simulated using PV Syst software. The paper started with a pre-feasibility study of a grid-connected photovoltaic system using PV Syst. Software with an extensive database of meteorological data, including global daily horizontal solar irradiance, and a database of various renewable energy system components from different manufacturers. In this work, a comprehensive literature review of agricultural solar photovoltaic systems is conducted, with a particular focus on grid-connected systems, followed by a design procedure for grid-connected solar photovoltaic systems. The planned photovoltaic system will generate a total of 400 KWp of electricity. This generated electricity can drive down electricity prices by exporting excess electricity to the national grid. In addition, solar power systems are fuel-efficient and have a low environmental impact.

Multi-Input Deep Convolutional Neural Network Model for Short-Term Power Prediction of Photovoltaics.

Along with the increasing prominence of energy and environmental issues, solar energy has received more and more extensive attention from countries around the world, and the installed capacity of photovoltaic power generation, as one of the main forms of solar energy development, has developed rapidly. Solar energy is by far the largest available source of energy on Earth, the use of solar power photovoltaic system has the advantages of flexible installation, simple maintenance, environmentally friendly, etc., by the world's attention, especially the grid-connected photovoltaic power generation system has been rapid development. However, photovoltaic power generation itself is intermittent, affected by irradiance and other meteorological factors very drastically, and its own randomness and uncertainty are very large, and its grid connection affects the stability of the entire power grid. Therefore, the short-term prediction of photovoltaic power generation has important practical significance and guiding meaning. Multi-input deep convolutional neural networks belong to deep learning architectures, which use local connectivity, weight sharing, and subpolling operations, making it possible to reduce the number of weight parameters that need to be trained so that convolutional neural networks can perform well even with a large number of layers. In this paper, we propose a multi-input deep convolutional neural network model for PV short-term power prediction, which provides a short-term accurate prediction of PV power system output power, which is beneficial for the power system dispatching department to coordinate the cooperation between conventional power sources and PV power generation and reasonably adjust the dispatching plan, thus effectively mitigating the adverse effects of PV power system access on the power grid. Therefore, the accurate and reasonable prediction of PV power generation power is of great significance for the safe dispatch of power grid, maintaining the stable operation of power grid, and improving the utilization rate of PV power plants.

Online Control of Smart Inverter for Photovoltaic Power Generation Systems in a Smart Grid

The main purpose of this study is to engage in research on a grid-connected photovoltaic (PV) power generation system smart inverter. The research content includes a smart maximum power point tracking (MPPT) controller and an inverter with power regulation. First, use the PSIM software package to establish the simulation environment of the grid-connected photovoltaic power generation system and use the Sanyo HIP-186BA19 photovoltaic module to form a 744 W system for simulation. In order to enable the photovoltaic module array (PVMA) to output the maximum power under different solar insolation and ambient temperature, the architecture is based on the extension theory-based smart MPPT method to improve the dynamic response and steady-state performance of photovoltaic power generation systems compared to perturb and observed (P&O) MPPT. When the sunshine is 1,000 W/m2, the photovoltaic power generation system adopts the extension theory-based maximum power tracking method. The time required to track the maximum power point is only 0.32 s, and the steady-state ripple is only 4.127 W. However, using the traditional P&O method requires 0.741 s to track the maximum power point, and the steady-state ripple reaches 18.131 W. Thus, the dynamic response speed of the maximum power tracking method proposed is 50% faster than that of the P&O method. The steady-state performance is also better compared to the P&O method. At the same time, a simple proportional-integral (PI) controller is used to regulate the DC-link voltage, output voltage, and current of the inverter to make the voltage of the grid-connected point stable at an effective value of 220 V. Then, the voltage-power control technology is added to the photovoltaic grid-connected inverter, and a simple proportional-integral controller is used to regulate the output of the smart inverter reactive power to improve the power quality of grid voltage. Finally, simulation and experimental results are used to verify the effectiveness of the regulation performance of the developed smart inverter.

Design of a Three Phase Z-Source Inverter for Photovoltaic Systems

Due to the danger of extinction of fossil energy resources and their harmful effects on the environment, interest in renewable energy sources has increased today. Furthermore, the photovoltaic energy, which is among renewable energy sources, has started to gain importance day by day. Especially, grid-connected Photovoltaic (PV) power generation systems have begun to be installed and used widely. In the grid-connected power generation systems, variable environmental conditions cause the DC voltage obtained from the PV systems to vary continuously. In the applications where traditional inverters are used, additional DC/DC converters are required to obtain an output at the desired frequency and amplitude. On the other hand, Z-source inverters which are a new concept can perform this raising and lowering process without the need for any intermediate circuit elements, thanks to the impedance network in their structures. For this reason, in this paper, Z-source inverter is designed for the PV systems. Z-source inverter modeling with impedance network is realized by using a simple boost switching method, and the modulation index and duty cycle parameters are adjusted to increase the DC voltage applied to its input. It is observed from the simulation results that using of the Z-source inverter is proper and efficient in the PV power generation systems.

New Control Approach of Multicell Stacked Cell Inverter for Solar Photovoltaic System

This paper presents the study, modelling, and simulation of the DCSVM (Duty Cycle Space Vector Modulation) control technique applied to a new inverter topology dedicated to isolated or grid-connected photovoltaic systems using the MATLAB/Simulink software. This inverter is based on the structures of a stacked multicell converter (SMC) and an H-bridge. This new topology allows the voltage stresses of the converter to be distributed among several switching cells. It also allows the input voltage to be divided into several fractions so that the number of switching power semiconductors is reduced. The DCSVM is a control technique that generates control signals to the two-level voltage converter as well as the intermediate times. The main advantage of this control technique is the reduction in the number of calculations, especially for the trigonometric functions and the generation of the reference voltage. In this contribution, the general topology of this microinverter is described and the DCSVM control technique is presented. Finally, simulation results, the efficiency of this topology, and the validity of the DCSVM control in a grid-connected PV generation system are discussed. The results obtained are very satisfactory.

Compensation of Unbalanced Low-Voltage Grids Using a Photovoltaic Generation System with a Dual Four-Leg, Two-Level Inverter

In this paper, a grid-connected photovoltaic (PV) generation system is proposed with the purpose of providing support to low-voltage grids, namely through the elimination or attenuation of the grid imbalances. This compensation must consider the load types, which can be either linear or non-linear, and whether the reactive power and current harmonics generated by the non-linear loads need to be compensated in addition to the unbalanced active power. This must be well considered, since the compensation of all aspects requires oversized PV inverters. Thus, the different unbalanced compensation schemes are addressed. Several schemes for the generation of the inverter current references taking into consideration the compensation and load type are presented. For this PV generation system, a dual four-leg, two-level inverter is proposed. It provides full unbalanced compensation owing to the fourth leg of the inverter and also extends the AC voltage, which is important when this compensation is required. To control this inverter, a control scheme for the inverter that considers several compensation factors is proposed. A vector voltage modulator associated with the controller is another aspect that is addressed in the paper. This modulator considers the balance between the DC voltages of the inverters. Several compensation schemes are verified through computational tests. The results validate the effectiveness of the proposed PV generation system.

Analysis of the Economic Viability of the Installation of a Photovoltaic System at Jorge de Abreu Regional Hospital in Sinop-MT

Brazilian consumers have the possibility to produce their own energy using renewable sources or qualified cogeneration and even provide the surplus for the distribution network of their locality, as determined by the publication of Normative Resolution 482/2012 by the National Electric Energy Agency (ANEEL). In view of this, the use of photovoltaic systems for electricity generation has grown surprisingly, reaching the mark of 8 gigawatts of installed power on Brazilian soil in the year 2021 [1]. In Brazil, public agencies represent 0.1% with 4.7MW installed [1], and in the state of Mato Grosso 0.38% [14]. Thus, aiming at the rise of electricity generation in public buildings, due to the possibility of reducing costs with the electric bill, the present work deals with the dimensioning, budget quotation and economic feasibility analysis regarding the installation of a grid-connected photovoltaic power generation system to meet the energy demands of the Jorge de Abreu Regional Hospital in the city of Sinop, Mato Grosso state, Brazil. Whose, after carrying out the necessary research based on the techniques present in the economic sciences, as Minimum Attractiveness Rate (MRA), Net Present Value (VLP), Internal Rate of Return (IRR) and calculation of Payback. The present work considered a grid-connected solar energy generation system of 585 kW to supply the hospital's average monthly consumption of 93.829 kWh/month. The investment analysis showed that the project for the implementation of the photovoltaic system will have its NPV viable from the 4th year of installation and the Payback (return on investment), observing the monetary corrections, of approximately 4,29 years, thus configuring the system as economic financially.

Analysis of the Economic Viability of the Installation of a Photovoltaic System at Jorge de Abreu Regional Hospital in Sinop-MT

Brazilian consumers have the possibility to produce their own energy using renewable sources or qualified cogeneration and even provide the surplus for the distribution network of their locality, as determined by the publication of Normative Resolution 482/2012 by the National Electric Energy Agency (ANEEL). In view of this, the use of photovoltaic systems for electricity generation has grown surprisingly, reaching the mark of 8 gigawatts of installed power on Brazilian soil in the year 2021 [1]. In Brazil, public agencies represent 0.1% with 4.7MW installed [1], and in the state of Mato Grosso 0.38% [14]. Thus, aiming at the rise of electricity generation in public buildings, due to the possibility of reducing costs with the electric bill, the present work deals with the dimensioning, budget quotation and economic feasibility analysis regarding the installation of a grid-connected photovoltaic power generation system to meet the energy demands of the Jorge de Abreu Regional Hospital in the city of Sinop, Mato Grosso state, Brazil. Whose, after carrying out the necessary research based on the techniques present in the economic sciences, as Minimum Attractiveness Rate (MRA), Net Present Value (VLP), Internal Rate of Return (IRR) and calculation of Payback. The present work considered a grid-connected solar energy generation system of 585 kW to supply the hospital's average monthly consumption of 93.829 kWh/month. The investment analysis showed that the project for the implementation of the photovoltaic system will have its NPV viable from the 4th year of installation and the Payback (return on investment), observing the monetary corrections, of approximately 4,29 years, thus configuring the system as economic financially.

Visualized calculation of regional power grid power data based on multiple linear regression equation

Abstract The power generation of distributed power generation systems in regional power grids is mainly affected by external environmental factors, and there are volatility and intermittent power generation issues. This paper establishes a relatively simple multiple linear regression prediction model to predict grid-connected photovoltaic power generation systems. The article uses a hybrid modelling method to filter more important weather forecast input variables through a step-by-step linear regression method to realize the visual calculation of power data. The research results show that the multiple linear regression equation methods proposed in the article have pervasive application value in the actual application of solar photovoltaic power consumption data.

Research on the Influence of Photovoltaic Module Power Generation Efficiency and Manufacturing Technology on Power Grid Connection

The power generation efficiency of a photovoltaic power generation system is closely related to factors such as the material of the photovoltaic module, the tilt angle of the module installation, and the power of the module. At present, the output power of large-scale grid-connected photovoltaic power generation systems has large fluctuations and strong randomness. In order to accurately predict the output power of photovoltaic power stations to solve the problems of peaking and dispatching caused by large-scale photovoltaic grid-connected power generation to the grid. The article introduces the design of single-phase photovoltaic grid-connected inverter system and its control system based on big data technology. The research found that the photovoltaic manufacturing and grid-connected algorithms proposed in this paper can achieve the best power generation benefits of photovoltaic power plants, while improving the operation and maintenance efficiency of photovoltaic power plants.

Research on Reliability of Grid Connected Photovoltaic Renewable Generation System

Renewable energy sources are increasingly being implemented in power systems to curb global warming and improve generation adequacy. These renewable sources include Hydro, wind, tidal, and solar power systems. Since Pakistan experiences decent solar irradiation throughout the year, the most viable renewable energy option is photovoltaic generation. Before solar systems are implemented, the proposed design is first simulated using design software such as MATLAB-Simulink to correct and adjust parameters to attain the DC voltage and current through the irradiation and environment temperature. Reliability studies and analysis are performed on the simulated systems to ascertain the success and long life before the system components’ failure. In this thesis, the grid-connected PV system’s reliability model established based on the reliability block diagram method using the MIL-HDBK-217F handbook. The handbook provides the methodology of calculating failure rates of specific physical electronics operations. The mean time to failure (MTTF) and Mean time to repair (MTTR) of the system is calculated from the overall system reliability. Photovoltaic power output varies greatly, and it is dependent on solar irradiation and temperature, resulting in intermittent and variable energy production. All of these considerations have a significant effect on the entire system adequacy of the power generation system. This study uses a probabilistic analytical methodology to develop comprehensive reliability models of grid-connected Photovoltaic generation systems.

Performance Analysis of Maximum Power Point Tracking for Two Techniques with Direct Control of Photovoltaic Grid -Connected Systems

ABSTRACT The present study presents two techniques of Maximum Power Point Tracking (MPPT) via DC/DC converter to enhance the performance of the grid-connected Photovoltaic (PV) generation system to participate effectively within microgrids. The two techniques of MPPT are Perturb-Observe (P&O) and Incremental Conductance (IC). The variation of the solar radiation and temperature is considered during employing the two MPPT techniques. Besides, the performance of the system under the random variation of solar radiation was investigated. The authors used two types of controllers at the three-phase inverter, Proportional Integral (PI) and H-infinity Control (H∞C). The output voltage, current, and power at each type of inverter controller are compared along with the two techniques of MPPT. The effectiveness of the developed controllers together with MPPT techniques is demonstrated by comparing the obtained results with some previously reported research in the literature. In the case of MPPT via P&O and IC techniques along with the H∞C controller, the results show that the technique of IC is more robust, and the obtained output power is well matched with the references one as compared with the P&O technique which records a 7% error from MPP. Besides, the P&O technique has a high voltage and current ripple with a percentage of 20% at the starting time of the simulation.

Modelling and Performance Analysis of Synchronous Reference Frame Phase-Locked Loop for Three-phase Grid-connected PV Generation System

Due to the introduction of the feed-in tariff policy mechanism in many countries, the grid-connected Photovoltaic (PV) generation system becomes new attractions as it encourages the energy producers to generate and supplies electricity to the grid. The characteristic of the inverter’s voltage waveform, its amplitude, phase-angle and phase sequence are vital parameters for effective PV-grid synchronization. This paper presents a double stage converter, DC-DC boost conversion included to maximum power point tracking (MPPT) is achieved. Second stage DC-AC conversion is achieved using voltage source inverter (VSI). Grid connected synchronization is achieved by using synchronous reference (SRF) base phase locked loop (PLL). A details design and model for each section of the proposed system are also presented. The result shows that the implementation of synchronous reference frame (SRF) with PLL able to good achieved.