Nonlinear controller design for maximum power tracking in grid connected photovoltaic systems (original) (raw)
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Abstract: This paper deals with the design of a nonlinear controller for single-phase grid-connected photovoltaic (PV) renewable energy systems to maintain the current injected into the grid in phase with grid voltage and to regulate the DC link voltage and to extract maximum power point tracking (MPPT).The system configurationincludes a photovoltaic generator, DC-DCconverter, DC-AC inverter coupled to grid network. The controller is designed using thebackstepping control to optimize the PV energy extraction and to achieve unity power factor, the controller is based on an averaged nonlinear state space model of the controlled system. This is carried out via controlling the duty ratio of the DC-DC converter and DC-AC inverter. An integral action was added in order to robustify the controller with respect to parameter variations and disturbances.The synthesis of the regulator wasachieved by having recourse to advanced tools of nonlinearcontrol such as asymptotic stability in the sense of Lyapunov. The performance of the proposed controller is evaluated through numerical simulation in terms of delivering maximum power and synchronization of grid current with grid voltage under changes in atmospheric conditions. Keywords: Grid-connected photovoltaic systems, Maximum power point tracking (MPPT), Unity power factor, Backstepping controller, Asymptotic stability.
Control of a grid connected photovoltaic system
2015 International Conference on Renewable Energy Research and Applications (ICRERA), 2015
This paper addresses the problem of controlling grid connected photovoltaic (PV) systems that are driven with microinverters. The systems to be controlled consist of a solar panel, a boost dc-dc converter, a DC link capacitor, a single-phase full-bridge inverter, a filter inductor, and an isolation transformer. We seek controllers that are able to simultaneously achieve four control objectives, namely: (i) asymptotic stability of the closed loop control system; (ii) maximum power point tracking (MPPT) of the PV module; (iii) tight regulation of the DC bus voltage; and (iv) unity power factor (PF) in the grid. To achieve these objectives, a new multiloop nonlinear controller is designed using the backstepping design technique. A key feature of the control design is that it relies on an averaged nonlinear system model accounting, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of the PV panel. To achieve the MPPT objective, a power optimizer is designed that computes online the optimal PV panel voltage used as a reference signal by the PV voltage regulator. It is formally shown that the proposed controller meets all the objectives. This theoretical result is confirmed by numerical simulation tests.
Grid-connected of photovoltaic module using nonlinear control
Proceedings - 2012 3rd IEEE International Symposium on Power Electronics for Distributed Generation Systems, PEDG 2012, 2012
The problem of controlling single-phase grid connected photovoltaic (PV) system is considered. The control objective is fourfold: (i) asymptotic stability of the closed loop system, (ii) maximum power point tracking (MPPT) of PV module (iii) tight regulation of the DC bus voltage, and (iv) unity power factor (PF) in the grid. A nonlinear controller is developed using the backstepping design technique based on an averaged nonlinear model of the whole controlled system. The model accounts, on the one hand, for the nonlinear dynamics of the underlying boost converter and inverter and, on the other, for the nonlinear characteristic of PV panel. It is formally shown, through theoretical analysis and simulation results, that the proposed controller does achieve its objectives.
International Journal of Electrical and Computer Engineering (IJECE), 2017
This paper presents a robust control strategy for a grid connected photovoltaic system with a boost converter by using an integral Backstepping method based on a nonlinear state model, which guarantees the Lyapunov stability of the global system. The system has tracked precisely the maximum power point, with a very fast response and the unit power factor has been observed under different atmospheric conditions. Moreover, the best advantage of the controller is that it's a good corrector of the grid perturbation and system parameter disturbance. The simulation result has demonstrated the performance of this strategy.
This work presents a new control method to track the maximum power point of a single-phase gridconnected photovoltaic (PV) system. This converter is built on two stages: a DC/ DC stage and a DC/ AC stage. The two blocks are bound by a DC voltage intermediate bus. We seek the achievement of three control objectives: (i) maximum power point tracking (MPPT) of (PV) module. (ii) tight regulation of the DC bus voltage and (iii) unity power factor (PF) in the grid. To meet these objectives, a multi-loop controller is designed using the sliding mode technique based on an averaged nonlinear model of the whole controlled system. It is formally shown, through analysis and simulation results that the developed strategy control actually meets its objectives.
Adaptive Backstepping Controller Design Based MPPT of the Single-Phase GridConnected PV System
International Journal of Intelligent Engineering and Systems, 2021
The environmental condition changes lead to obvious fluctuation in photovoltaic panels’ output power. Therefore, to make efficient use of photovoltaic (PV) systems the maximum power point tracking (MPPT) controllers are required. Many classical methods are proposed to track the MPP, but they will lead to a high power drop when rapid changes in the atmospheric conditions occur, which necessities a robust controller with high performance. In such a manner, the proposed controller is designed for this purpose. There are two stages of the proposed controller: The artificial neural network (ANN) based the first stage that generates the PV panel optimal voltage and the second phase consists of a non-linear adaptive backstepping control, which is able to follow this optimum voltage by acting on the DC/DC boost converter’s duty cycle. The input-output linearization technique is based the suggested controller. The last is robust and safe from the parameters fluctuation, load variation, and t...
Nonlinear control and stability analysis of single stage grid-connected photovoltaic systems
International Journal of Electrical Power & Energy Systems, 2020
This work presents the control development of a single stage grid-connected photovoltaic (PV) system. The topology used by the PV system consists of two PV panels, a single-phase half-bridge inverter using two DC link capacitors, and an LCL filter in the grid side. The aim is to design a nonlinear controller to ensure simultaneously the following three objectives: (i) PV panels to provide their maximum power, (ii) balanced power exchange by regulating the DC link voltage, and (iii) power factor correction, i.e. grid current in phase with grid voltage. In order to fulfill these objectives, a multi-loop controller is designed by using back-stepping and Lyapunov approaches for the power factor correction objective and a filtered PI regulator to ensure the power balance between the grid and the PV panels. The controller performances are formally analyzed using an average large signal model. The performance of the proposed controller is shown by means of simulation results in MATLAB/ SimPowerSystems environment.
International Journal of Multidisciplinary and Current Educational Research, 2023
Among the different renewable energy resources, photovoltaic (PV) energy has found increased attention and wide attraction from researchers in several applications, for its capabilities of direct electric energy conversion without any environmental damage, ease of implementation, flexibility in size and low operation cost. The output power induced in the PV modules depends on solar radiation and temperature of the solar cells. To maximize the efficiency of the system, it is necessary to track the maximum power point of the PV array. In this study, two direct maximum power point tracking (MPPT) algorithms based on backstepping and synergetic approaches for a photovoltaic power system are investigated. Both nonlinear algorithms are designed to be applied to a boost DC-DC converter in order to achieve an optimal PV array output voltage. The simulation results validate the rapid tracking and efficient performance of the two controllers. For further validation of the results, it also provides a comparison of the two proposed controllers with conventional perturb and observe (P&O) under abrupt changes in environmental conditions.
MPPT for Photovoltaic System Using Nonlinear Controller
International Journal of Photoenergy, 2018
Photovoltaic (PV) system generates energy that varies with the variation in environmental conditions such as temperature and solar radiation. To cope up with the ever increasing demand of energy, the PV system must operate at maximum power point (MPP), which changes with load as well as weather conditions. This paper proposes a nonlinear backstepping controller to harvest maximum power from a PV array using DC-DC buck converter. A regression plane is formulated after collecting the data of the PV array from its characteristic curves to provide the reference voltage to track MPP. Asymptotic stability of the system is proved using Lyapunov stability criteria. The simulation results validate the rapid tracking and efficient performance of the controller. For further validation of the results, it also provides a comparison of the proposed controller with conventional perturb and observe (P&O) and fuzzy logic-based controller (FLBC) under abrupt changes in environmental conditions.