Particle swarm optimization algorithm-based PI inverter controller for a grid-connected PV system.

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.

Grid-connected photovoltaic (PV) systems require a power converter to extract maximum power and deliver high-quality electricity to the grid. Traditional control methods, such as proportional-integral (PI) control for DC-link voltage regulation, often struggle under abnormal operating conditions, resulting in voltage fluctuations and instability in the maximum power point tracker (MPPT). This paper proposes a synergistic control strategy that combines a musical chairs algorithm (MCA) MPPT with sliding mode control (SMC) together for the boost converter DC-link control. This approach enhances DC-link voltage stability by switching the MPPT to SMC of the boost converter when the DC-link voltage exceeds the predefined limit. This strategy enhances the stability of the DC-link voltage and allows for a smaller DC-link capacitor, thereby reducing system cost and improving the power quality of PV systems. A phase-locked loop (PLL) further ensures effective grid synchronization. The reduction in DC-link voltage overshoot (from 570 V to 522 V) improved stability under varying irradiance conditions. Moreover, a 48 V reduction in overshoot voltage and a 66% decrease in DC-link voltage ripple (standard deviation from 17.93 V to 5.92 V) occurred. Simulation and experimental results demonstrate the superiority of the proposed strategy compared to the case without coordination between the DC-DC converter and inverter controllers, particularly under challenging conditions.

In this paper, a direct power control (DPC) approach is used to control the active and reactive power injection into the grid from a photovoltaic (PV) unit. The dynamics of active and reactive power are used to develop the dynamical model of the three-phase grid-connected PV (GCPV) system while a nonlinear adaptive technique is employed to design the proposed controller. The parametric uncertainties are incorporated within the dynamical model of three-phase GCPV systems by considering the parameters as totally unknown. The unknown parameters are estimated through adaptation laws and control Lyapunov functions (CLFs) are formulated during the different stages of the controller design process to ensure the overall stability of the GCPV system. The theoretical stability of the three-phase GCPV, with the proposed control scheme, is analyzed through the negative semi-definiteness of the derivatives of CLFs. Simulations are carried out to further validate the performance of the proposed control scheme on a three-phase GCPV system in terms of injecting power (both active and reactive) into the grid along with the power quality. Simulation results demonstrate effectiveness of the proposed controller as compared to an existing sliding mode controller (SMC).

In modern power systems, photovoltaic (PV) generation plays a vital role in sustainable energy supply. PV systems generate DC power, which is converted to AC using built-in converters for grid integration. The quality of power injected into the grid is crucial, especially in the presence of plug-in electric vehicles (PEVs) and non-linear loads, which introduce harmonics and dynamic disturbances. To enhance power quality, advanced control strategies are employed. This paper presents a comparative study of direct-quadrature (DQ) control techniques using traditional proportional-integral (PI) controllers and fuzzy logic controllers (FLCs) in a grid-connected PV system. The DQ control method simplifies the regulation of active and reactive power by transforming three-phase signals into a rotating reference frame. While PI controllers are widely used, they often struggle with non-linearities and load variations. FLCs, on the other hand, offer adaptive control without requiring precise mathematical models, making them more effective under dynamic conditions. The system under study includes PV generation, PEVs, and non linear loads. Performance metrics such as total harmonic distortion (THD), voltage stability, and power factor are analyzed. Results show that fuzzy controllers significantly improve power quality and system response.

This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

This paper presents a three-phase grid-connected photovoltaic generation system with unity power factor for any situation of solar radiation. The model of the PWM inverter and a control strategy using dq0 transformation are proposed the system operates as an active filter capable of compensate harmonic components and reactive power, generated by the other loads connected to the system. A input voltage clamping technique is proposed to control the power between the grid and photovoltaic system, where it is intended to achieve the maximum power point operation. Simulation results and analyses are presented to validate the proposed methodology for grid connected photovoltaic generation system.

This paper presents nonlinear adaptive control scheme for improving the power quality in single-phase grid-connected photovoltaic (PV) systems. For this purpose, an LCL filter is used at the output-side of the voltage source inverter (VSI) in the single grid-connected PV system. In this paper, the proposed adaptive controller is designed for the VSI by considering the average model of the VSI while considering only the dynamics of the LCL filter. The proposed controller enhances the power quality of the system by maintaining the values of total harmonic distortions (THDs) at lower levels as it estimates the parameters of the LCL filter using adaptation laws. These adaption laws are obtained in such a way that it is not essential to know exact parameters of the LCL filter. The parameter estimation capabilities of the proposed scheme are ensured through the tracking performances of different state variables associated with the dynamics of the LCL filter. The convergences of tracking errors are ensured during the different stages of the controller design process using the Lyapunov stability analysis technique and the stability of the overall system is also analyzed in this paper. The improvements in the power quality, using the proposed nonlinear adaptive control scheme, are demonstrated on a 3.5 kW single-phase grid-connected PV system by considering different operating conditions. The results are mainly discussed in terms of THDs in the current injected into the grid and also compared with a sliding mode controller (SMC).

Assesment of grid-connected photovoltaic systems in the Kuwaiti climate

Unified Power Quality Conditioner (UPQC) based distributed generating systems powered by renewable energy have struggled with power quality control under variable loads and renewable inputs. Key challenges include maintaining voltage stability, reducing harmonics, and integrating diverse energy sources effectively, all while seeking cost-effective solutions and enhancing real-time control strategies. By employing Multi-Strategy Enhanced Osprey Algorithm (MSEOA) for UPQC, this study improves power quality in a three-phase low voltage network connected to hybrid distributed generation (DG) system. It emphasizes the combination of solar photovoltaic or PV and wind turbine sources and examines this method with conventional proportional-integral (PI) controllers. The proposed method features a 4-wire, 3-phase electrical distribution network that actively injects power into the grid, improving power quality by reducing current and voltage harmonics and enhancing power factor. The investigation evaluates the dynamic and steady-state performance of the MSEOA-based UPQC against the PI controller using simulation findings and offers insights into the active power flow regulated by converters. At operating conditions (OPC), the Total Harmonic Distortion (THD) on load voltage proved to be 2.5%, 1.65%, 1.65%, and 1.8% for OPC1, OPC2, OPC3, and OPC4, respectively. These results show the advantageous results of the proposed approach in power quality optimization.

This paper deals with the adaptive estimation of frequency observation (AEFO) based technique for compensating the harmonics component of two-stage grid-connected solar photovoltaic (PV) system. The maximum PV power is extracted using maximum power point tracking (MPPT) algorithm. Moreover, the input DC voltage of the voltage source converter (VSC) is maintained at desired level using a proportional integral (PI) controller. The AEFO control injects the required reactive component, which shapes the balanced grid currents. Moreover, the active power is injected in to the grid, which eliminates the harmonics in the grid currents. Using this controller, the fundamental reference currents are estimated using nonlinear load currents. This system maintains the grid current total harmonic distortion (THD) in accordance to the IEEE 519 standard. The dynamic response is improved by adding the PV feed-forward term with the estimated magnitude of i eα and i eβ current quantities. This control improves the dynamic response when insolation is changed and also provided a good response when switched from PV array to DSTATCOM and vice versa. Moreover, the power quality issues such as load unbalancing, power factor correction and reduced the grid side currents harmonics. Test results has shown the reactive power compensation of balanced and unbalanced nonlinear loads and the steady-state and dynamic performances of the system and PV array to DSTATCOM and vice-versa.

Aiming at the low power level of the two-level Z-source inverter, the current and voltage harmonic distortion rate is high, the output power quality is low, The diode Neutral Point Clamp (NPC) three-level Z source inverter has insufficient boost capacity, and the capacitor voltage stress is low, the Z source network of the three-level inverter is improved and applied to photovoltaic grid-connected. In order to speed up the dynamic response speed of the quasi-Z-source photovoltaic grid-connected system, and for the quasi-Z-source photovoltaic gridconnected system with the existing current inner loop control output harmonic distortion rate is high, and the steady-state error is large. the power feedforward bacterial foraging proportional complex integral (BFOA-PCI) control method is put foreward. The system about this method reduces the steady-state error through the PCI controller, and adds the bacterial foraging optimization proportional coefficient KP and integral coefficient Ki , makes KP and Ki any the optimal conditions can be achieved, and introduces the output power feedforward of the photovoltaic array in the voltage outer loop, and its output is used as the reference value of the current inner loop. The method speeds up the system’s response changes to the external environment, reduces the harmonic distortion rate, improves steady-state accuracy and the output power quality.

This paper introduces the simulation and analysis of a three-phase large-scale grid-connected solar Photovoltaic (PV) system in order to assess the effect of integrated PV grid-connected mode on the power quality of the utility grid. The study takes into account the effect of solar system power variation as well as the PV inverter's introduction of penetrating harmonics into the system. The simulation of the system is done in MATLAB software using the SIMULINK environment and is tested by the Pysyst program. Where it is done in real-time with an actual case study on a 1620-kW PV array connected to an 11-kV grid via a three-level Voltage Source Converter (VSC). The technical data was recorded, and the system's power quality was examined. The grid-connected PV system's Performance Ratio (PR) is assessed to determine the PV system's reliability and grid connectivity.

Recently, the demand for small grid-connected photovoltaic (PV) systems has been rapidly increasing; this is due to the reduction in the costs of grid-connected storage systems as compared to those of the stand-alone ones. Notably, the performance of the solar tracking system is not only depending on the types but also the region that they are set up and used. To understand how solar tracking systems work globally, we need to know their performance in each country and even the different parts of a country. In this study, two grid-connected PV systems with 250 W solar modules were used to investigate the efficient improvement of a single-axis sun tracking system in Central Vietnam. First, a mechanical tracking device with a linear actuator and a controller was designed and then its performance was comprehensively investigated with a grid-connected PV system. In addition to evaluating the energy gain by the tracking system, this study also considered the energy consumption of the linear actuator with its controller and a small grid-connected PV system; this has generally been omitted in previous works. Experimental results indicate that the total energy consumption of the tracking system was approximately 2–8% of the energy generated by the grid-connected PV system. The maximum overall energy generation was confirmed to have increased by up to 30.3% on a sunny day upon using the proposed tracking system; further, the net energy gain by using the sun tracker was ascertained to be 15.2% in average weather conditions. Based on the success of this work, we will keep experimenting with other parts of Vietnam. Also, we will collaborate with colleagues in other countries to create a guideline for understanding and using the solar tracker regionally and globally.

Nowadays, due to the high-scale penetration of photovoltaic systems, reliable and efficient grid-connected photovoltaic (PV) systems utilizing the advances of power electronics and control system technology are desirable. Thus, single-stage grid-connected photovoltaic systems, have gained attention, especially in low voltage applications. However, PV systems exhibit nonlinear behavior that could negatively affect the performance of the system if they are not adequately compensated for. In this dissertation, using the general structure for the synchronous dq0 frame, a single-stage three-phase grid-connected photovoltaic system, and a single-stage single-phase grid-connected PV system, both with a nonlinear control strategy, are developed to track the maximum power and to control the active and reactive power, without the necessity of an additional power converter. A novel trajectory of the reference current is obtained online taking into account the dynamics of the DC link capacitor and the switching function of the inverter. Unlike to the three-phase system, the single-phase system includes a novel method to mitigate the double line-frequency current ripple of the PV array, which is the major drawback of the single-phase PV inverter. Moreover, based on the preceded work, the nonlinear controller is combined with adaptive control to estimate the unknown disturbances that physically could appear in the circuit and affect the performance of the system. The stability of the systems and boundedness of signals are demonstrated by Lyapunov stability analysis. Simulation results show the effectiveness and robustness of the proposed controllers to track the maximum power and to control the active and reactive power.

A novel adaptive command-filtered backstepping sliding mode control for PV grid-connected system with energy storage