Backstepping Control of Smart Grid-Connected Distributed Photovoltaic Power Supplies for Telecom Equipment (original) (raw)
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2020
In this paper, a grid connected PV system acting as shunt active power filter for power quality enhancement is presented. Further, a DC-DC boost converter is used to interface the photovoltaic generator with the grid, which provides a continuous power flow from the PV generator into the grid through a Voltage Source Inverter (VSI). Hence, a nonlinear backstepping control method with predictive direct power control for the shunt active power filter side is presented, and a suitable backstepping DC-DC boost converter is also developed, with a view to reduce harmonic currents and insuring reactive power compensation under nonlinear loads variations on the utility grid, and also extracts the maximum amount of power from the photovoltaic generator. Processor in the Loop (PIL) co-simulation results prove the performances efficiency of the implemented control algorithms under a nonlinear load operating condition.
International Journal of Electrical and Computer Engineering (IJECE), 2023
A novel nonlinear backstepping controller based on direct current (DC) link voltage control is proposed in three-phase grid-connected solar photovoltaic (PV) systems to control the active and reactive power flow between the PV system and the grid with improved power quality in terms of pure sinusoidal current injection with lower total harmonic distortion (THD), as well as to ensure unity power factor, or to compensate for reactive power required by the load, i.e., the electrical grid. The output power of the PV array is supplied to the grid through a boost converter with maximum power point tracking (MPPT) control and an inverter. Simulation results of the proposed controller show good robustness under nominal conditions, parameter variations, and load disturbances, which presents the main advantage of this controller as compared to an existing controller. The performance of this work was evaluated using a MATLAB/Simulink environment.
Nonlinear controller design for maximum power tracking in grid connected photovoltaic systems
2015
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 backstepping technique based on an averaged nonlinear model of the whole controlled system. It is formally shown, through theoretical analysis and simulation results that the developed strategy control actually meets its objectives. Key-Words: photovoltaic system; maximum power point (MPP); boost converter; backstepping technique, unity power factor, lyapunov.
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.
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.
2011
The present work describes the analysis, modeling and control of an interleaved Boost converters and Buck power inverter used as a DCDC and DCAC power conditioning stage for gridconnected photovoltaic (PV) systems. To maximize the steadystate inputoutput energy transfer ratio a backstepping controller is designed to assure output unity power factor and a Maximum Power Point Tracking (MPPT) algorithm to optimize the PV energy extraction. The achievement of the DCAC conversion at unity power factor and the efficient PV's energy extraction are validated with simulation results.
Iet Renewable Power Generation, 2016
This paper deals with a double-stage single-phase grid-connected photovoltaic (PV) system operating, with an additional feed-forward control loop (FFCL). Due to the PV array being constantly subjected to abrupt solar irradiance change, the DC-bus voltage varies and can interfere in adequate PV system operation. Therefore, an FFCL is proposed to improve the DC-bus voltage dynamic response, and reduce the settling time and overshoot. The FFCL acts on the generation of the inverter current reference, such that the dynamic behavior of the current injected into the grid is also improved. Furthermore, the PV system performance is affected by problems associated with mismatching phenomena, such as partial shading. This problem can be overcome using the maximum power point tracking (MPPT) technique based on particle swarm optimization (PSO). The PSObased MPPT is compared to the conventional perturb & observe (P&O) MPPT technique, in order to highlight its effectiveness. In this paper, the PV system also performs active power-line conditioning. Thereby, whereas the step-up DC-DC converter carries out the MPPT, the proper inverter current reference is computed to inject active power into the grid, as well as perform power-line conditioning. The performance and effectiveness of the PV system are evaluated through extensive experimental tests.
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...
Backstepping based power control of a three-phase Single-stage Grid-connected PV system
International Journal of Electrical and Computer Engineering (IJECE), 2019
In order to reduce costs while maintaining superior performance, this paper presents a new control methodology of a three-phase grid connected photovoltaic system without using the intermediary DC/DC converter. Based on the synchronized nonlinear model of the whole photovoltaic system, two controllers have been proposed for the three-phase inverter in order to ensure the operation of the PV system at the maximum power point with unity power factor and minimum grid disturbance. Grid synchronization has been ensured by a three-phase 2nd order PLL (Phase-Locked Loop). The stability of each controller is demonstrated by means of Lyapunov analysis and evaluated under changing atmospheric conditions using the Matlab/Simulink environment, the simulation results clearly demonstrate the performance provided by each controller.
Advances in Modelling and Analysis C, 2019
This paper proposes a combined nonlinear backstepping approach with direct power control technique for improving power quality of a three-phase grid-connected solar energy conversion system. The presented system basically extracts maximum power from solar photovoltaic array, converts it into AC power via a voltage source converter, and supplies it to the grid and connected loads. The proposed system offers not only the function of grid connected PV system but also it acts as a shunt active power filter (PV-SAPF). The system intends to eliminate the poor power quality issues and provides current conditioning while operating in coherence under nonlinear load variations. In order to validate the proposed double function system, processor-in-the-loop (PIL) tests are carried out for steady state and dynamic regimes under a nonlinear load operating condition.