Phase Grid Connected PV System Research Articles

Comparative Study of DC/AC Inverter Control Techniques for Three Phase Grid Connected PV System

The goal of this project is to develop and analyze a three-phase grid-connected photovoltaic (PV) system with a 250KW power capacity with expandable property. The PI, Slide, and MPC methodologies are used to test three distinct inverter current control techniques. The dynamic performances of the three inverter control techniques are virtually comparable under grid connected working conditions, although the dynamic performances of the traditional PI control technique are slightly better and smoother than the other two inverter control techniques. The unity power factor criterion was reached by all techniques. The output power levels obtained using the sliding mode inverter control method are higher than those obtained using the PI and MPC methods. MPC's DC link voltage readings are also consistent and match the intended voltage levels.

A New Control Strategy for Three Phase Grid Connected PV System Under Severe Partial Shading Conditions

A New Control Strategy for Three Phase Grid Connected PV System Under Severe Partial Shading Conditions

Impact of Mission Profile on Reliability of Grid-Connected Photovoltaic Inverter

In recent decades intense demand for energy increases the utilization of Photovoltaic (PV) energy as an alternative to fossil fuels. Today’s PV energy shares a significant electricity demand with the advancements in power electronic technologies. Nevertheless, reliability performance of PV system is a major concern. Environmental conditions like mission profile (Solar Irradiance; Ambient Temperature), installation location impacts the performance of PV system. Researchers reported PV inverter as the critical component of PV system. Furthermore, reliability assessment of PV inverter considering environmental conditions is needed for the reliable operation. Therefore, the aim of this paper is evaluating the impact of mission profile on reliability (lifetime) of PV. To accomplish this, a 3-kW single phase grid connected PV system with full bridge PV inverter is considered as test case and modelled in PLECS. A 600V/30A IGBT from leading manufacturer is considered as power electronic switch in PV inverter. Top ten countries of PV market are identified and selected as installation locations, real time mission profile for one year at each installation location is considered. With this mission profile reliability assessment of PV inverter is carried out on test case. The results reveal that mission profile have considerable impact on reliability performance of PV inverter.

PV Systems Control Using Fuzzy Logic Controller Employing Dynamic Safety Margin under Normal and Partial Shading Conditions

Because of the unpredictable activity of solar energy sources, photovoltaic (PV) maximum power point tracking (MPPT) is essential to guarantee the continuous operation of electrical energy generation at optimal power levels. Several works have extensively examined the generation of the maximum power from the PV systems under normal and shading conditions. The fuzzy logic control (FLC) method is one of the effective MPPT techniques, but it needs to be adapted to work in partial shading conditions. The current paper presents the FLC-based on dynamic safety margin (DSM) as an MPPT technique for a PV system to overcome the limitations of FLC in shading conditions. The DSM is a performance index that measures the system state deviation from the normal situation. As a performance index, DSM is used to adapt the FLC controller output to rapidly reach the global maxima of the PV system. The ability of the proposed algorithm and its performance are evaluated using simulation and practical implementation results for single phase grid-connected PV system under normal and partial shading operating conditions.

Efficient Control of a Three Phase Grid Connected PV System

This paper presents a new control strategy of a photovoltaic system, which consists of a photovoltaic generator PVG coupled to a three phase load and three phase grid by a three phase voltage source inverter VSI without DC-DC converter. The controller is designed by using Backstepping method based on d-q transformation of a new model of the global system. The main goals of this control strategy are to achieve the maximum power point MPPT with very good precision and the unity power factor in level of the grid power flow. Mathematical analysis demonstrate the asymptotic stability of the controlled system and simulation results proved that the controller has achieved all the objectives with high dynamic performance in presence of atmospheric condition changes. Moreover, the proposed controller shows a very good robustness under system disturbance, which presents the most important advantage of this controller compared to the other control strategies. Furthermore, this controller can operate with a high efficiency with any kind of the load.

Reactive Power Control for Single-Phase GridConnected PV Inverter using Fuzzy Controller

This paper proposes grid system and its controlling techniques to regulate the continuous changes in operational requirements and deregulation problems. In the present scenario, the distribution energy systems play an important role in maintaining the power system reliability and stability in distribution domain. The proposed grid is a structure of PV and hybrid system. To achieve the maximum operation from the renewable sources an MPPT methods is proposed. This paper also proposes a concept for controlling of reactive power in single phase grid connected PV system. In order to achieve this reactive power control, this paper is implemented with different current regulated controllers such as conventional PI controller, PR controller, ASDM controller and Fuzzy Logic Controller. This proposed system with different controllers are tested and verified in MATLAB environment.

A Single Phase Grid Connected PV System working in Different Modes

The current grid standards for the single-phase residential PV system expect it to operate at Maximum Power Point Tracking (MPPT) mode under normal operating conditions and to maintain the voltage profile whenever a grid fault occurs. The proposed system supplies power to the load under stable conditions and the PV system works in MPPT mode. When the fault occurs at the Point of Common Coupling (PCC) and the voltage is reduced, the proposed controller maintains the voltage profile by injecting the current fed by the current controller at the PCC. The controller shifts from MPPT to the faulty mode and maintains voltage as per grid requirements. During islanding conditions, the PV system successfully caters to the requirements of the load by shifting the control from MPPT to islanding mode. When the PV system is in operation the power quality is enhanced

Integral Backstepping Control of Three phase Grid Connected Photovoltaic Systems for Power Optimization

We propose in this paper a nonlinear controller to optimize the operation of a photovoltaic device consisting of a PV generator, a three-phase inverter, and an LCL filter. Unlike traditional systems, this system is reliable and is not expensive, thanks to the absence of the DC-DC converter. In reality, we are trying to achieve two goals: (i) Search track and extract the maximum power from the PV generator (MPPT requirement); (ii) Inject this power into the network in the form of an alternating current which has the same pulsation as that of the network (UPF requirement). To achieve these objectives, the proposed controller was designed using non-linear design techniques, based on the nonlinear modeling of the photovoltaic system. Numerical simulation and its results showed the performance of the nonlinear controller and its ability to confront the challenges described in this article (MPP and UPF requirement), external disturbances and abrupt climatic changes.

A Novel Voltage Regulation Technique using Fractional Order PI Controller for A Three Phase Grid Connected Photovoltaic System

The integration of distributed generations (DG’s) to the grid has led to number of challenges apart from the advantages, one of the challenge associated is the voltage regulation. Photovoltaic (PV) system as a DG is considered as it has a better edge when compared to the other DG’s. The application of PV system to the grid requires extra compensating devices to mitigate the voltage regulation issues. A novel voltage regulation strategy for three phase grid connected PV system using fractional order proportional plus integral (FOPI) controller is proposed in this paper. The modelling&analysis of FOPI controller along with the integer orderproportional plus integral (IOPI) controlleris presented in this paper. FOPI controllers are designed in Matlab using FOMCON toolbox (Fractional order Modeling and Control).The simulation is consequently carried out in the Matlab/Simulink environment for both the controllers with resistive loads, resistive & inductive loadsand resistive, inductive & capacitive loads.The FOPI controller outperforms IOPI controller, results of simulation reflectthat controller using FOPI gives better performancewhen compared with the IOPI controller. The effectiveness ofthe FOPI controller confirms the authentication and the simulation results are deliberated for all the different loads.

Modelling and Analysis of Grid Connected Three-Phase Photovoltaic Inverter

Currently, there is urgent need of renewable energy as the conventional power sources are exhausting rapidly. A reliable and abundant source is solar energy using photovoltaic (PV) panels. Certain power converters like DC-DC converter and DC-AC inverter are used to interface PV panels to the main grid. MPPT algorithm is used for tracking maximum power from PV panels. The main objective of this paper is to simulate and analyse three phase grid connected PV system. A close loop control system using phase locked loop is modelled and simulated in MATLAB-Simulink environment to assure maximum real power flow from the PV source to the utility grid.

Nonlinear Predictive Control for Maximum Power Point Tracking and Unity Power Factor of a Three Phase Grid Connected PV System

We address in this paper the control of a three phase single stage grid connected PV system based on Nonlinear Continuous-time Generalized Predictive Control (NCGPC). Without using the intermediate DC/DC converter, the three-phase inverter must operate the photovoltaic system at its maximum power with a unit power factor. The NCGPC controller is based on a synchronized nonlinear model of the PV system. Grid synchronization is provided by a three-phase PLL (Phase-Locked Loop). The closed-loop stability is ensured by the convergence of the output-tracking errors to zero. The performance of the proposed control strategy is evaluated using rapid changes in atmospheric conditions, acting on the PV system, in MATLAB/SIMULINK environment. Obtained results demonstrate the high performance of the proposed control scheme.

Active and reactive power control of three phase grid connected PV system

This paper deals with active and reactive power control of a three phase grid connected photovoltaic system. Maximum power point tracking (MPPT) algorithm is used to track the MPP. The MPPT algorithm uses the IPV and VPV of the PV array and gives the MPP and a Vdc,ref. This voltage is then passed on to the inverter and then further to the three-phase grid. The behaviour of the active and reactive power of the grid which is supplied by the PV array is investigated. The various currents such as inverter current, grid current and load currents are also investigated. MATLAB/simulink has been used to carry out the simulations. The proposed work has also been experimentally verified.

Active and reactive power control of three phase grid connected PV system

Active and reactive power control of three phase grid connected PV system

Robust Nonlinear Controller Design for Three Phase Grid Connected PV Systems with Improved Power Quality

The development of photovoltaic systems has increased due to the high demand for clean and green energy. Used worldwide for distributed power generation, the photovoltaic power must not only be maximized, but also adapted to the global standards on harmonic emissions limits. Therefore, tracking the Maximum Power Point and filtering harmonics became necessary. A three-phase grid-connected Photovoltaic system consisting of a photovoltaic (PV) array, a boost converter and a three-phase PWM inverter coupled through a low-pass filter to the electrical grid is studied in this paper. Two new control designs are developed to maximize power in the side of PV panels and to impose a unity power factor in the side of the grid, the first for the three-phase grid-connected systems with an L-filter and the second for the same systems with an LCL-filter. Both controls are analyzed and compared in details and their stability is demonstrated using Lyapunov analysis. The theoretical analysis and simulation results clearly illustrate that the proposed controllers have achieved the objectives. In order to demonstrate the good performance of the LCL-filter in minimizing the harmonics produced by the inverter, a comparison between the frequency responses of the injected currents using the LCL-filter and the L-filter is carried out.

Three Phase Grid Connected PV System for Mitigation of Voltage and Current Harmonics Compensation Using SRF Method

Power quality is an all-encompassing concept for a multitude of individual types of power system disturbances. The presence of harmonics in power supply network poses a severe power quality problem that results in greater power losses in the distribution system, interference problems in communication systems and, sometimes, in operation failures of electronic equipment. This paper presents a three -phase active power filter for harmonic compensation which is consists of a series active power filter and a shunt active filter. The active filter connected in series to a source acts as a harmonic isolator between the sources and loads whereas the shunt active filter is connected in parallel with a load and suppresses the harmonic current produced by the load and. reduce the total harmonic distortion (THD). The voltage source inverter (VSI) is the core of an active power filter. The hysteresis current control is a method of controlling the VSI. Hysteresis control can be either of fixed band type or adaptive band type. In this paper, Synchronous Reference Frame (SRF) theory is implemented for the generation of reference current signals for the controller. Mat lab /Simulink and are used for simulation. From the simulation results it is confirmed that the filter topology is capable of compensating the load current and voltage harmonic distortion within the stipulated limits laid down by the IEEE 519 standard.

Modeling and Performance Analysis of Partial Feedback Linear Controlling Technique in Single Phase Grid Connected PV System

Modeling and Performance Analysis of Partial Feedback Linear Controlling Technique in Single Phase Grid Connected PV System

MODELING AND ANALYSIS OF SINGLE PHASE GRID CONNECTED PHOTOVOLTAIC SYSTEM

This paper gives a complete computer simulation program of a single phase grid connected PV system using Matlab/Simulink and SimPower System tool in order to monitor the performance of each unit of the system during a selected day in the year representing a sunny day and another cloudy day using the hourly data of load demand, solar radiation and temperature at the college of Engineering, Pune site, as a case study. The system consists of a PV array subsystem as the primary source of energy, the electric grid as an auxiliary source of energy, the battery bank as a stand by source that feeds the electrical load in case of grid failure. This paper also focuses on the operation control of the system. This control is on/off switch control according to modes of operation of the system and there is a control of inverter using PI controller to achieve the maximum power point of the PV array. Finally this paper gives the simulation results of the required system output parameters; PV output power, grid power, load power, battery power, and battery voltage and state of charge.

Backstepping Control for Maximum Power Tracking in Single- Phase Grid-Connected Photovoltaic Systems

The problem of maximum power point tracking (MPPT) in photovoltaic (PV) arrays is addressed considering a PV system including a PV panel, a PWM DC/AC inverter connected to single-phase grid. The maximum power point (MPP) of PV generators varies with solar radiation and temperature. To reduce the PV system cost, the MPPT is presently achieved without, chopper, resorting to solar radiation and temperature sensors. The proposed strategy involves a multi-loop nonlinear controller designed, using the backstepping design technique, to meet the three main control objectives i.e. (i) voltage reference generator designed to meet maximum power point tracking (MPPT), (ii) tight DC Link voltage regulation for a wide range voltage-reference variation and power factor correction (PFC) requirement must be satisfactorily realized. A formal analysis based on Lyapunov stability is developed to describe the control system performances. It is formally shown that the developed strategy control actually meets the MPPT requirement.

Simulation and Analysis of Two-Level Photovoltaic Grid-Connected System

As the power output of the photovoltaic (PV) cell changes with the insolation changing, PV cell temperature and cell voltage changing, it is necessary to control the operating voltage to draw the maximum power of the PV cell in order to increase system efficiency. Two-level three phase grid-connected PV system is designed. The forestage BOOST chopper adopt Incremental conductance algorithm to implement Maximum Power Point Tracking; The controller for the inverter system contains inner current loop and external voltage loop. According to the proposed control schemes, the phase and frequency of grid-connected current is the same as grid voltage, with the result of unity of the power, factor for power grid. The PV grid-connected system is built by MATLAB/SIMULINK, and the simulation results show that the proposed control schemes are validated.

Investigation of the behavior of a three phase gridconnected photovoltaic system to control active and reactive power with DPC

Abstract This paper proposes an extended direct power control (DPC) for a three-phase PWM multilevel inverter fed by photovoltaic generation system (PVGS) and connected of a grid. The model contains a detailed representation of the main components of the system that are the solar array, and the grid side inverter multilevel inverter NPC VSI. In order to extract the maximum amount of from the photovoltaic generator, we propose an intelligent control method (fuzzy logic controller) for the maximum power point tracking (MPPT) of a PVGS. The DPC approach for multilevel inverter NPC which makes it possible to achieve unity power factor (UPF) operation by directly controlling its instantaneous active and reactive power. The other is a fuzzy logic controller, in the multi-DC-bus voltage control loop, developed to provide active power command. To achieve UPF operation, the reactive power command is set to zero. It is shown via simulation results that the proposed DPC has high performance. Moreover, the controller multi DC bus link voltages based on fuzzy logic has excellent performance in transient and steady states, a good robustness, a good dynamic behaviour response, and a good rejection of impact of load disturbance.