Robust controller for interleaved DC-DC converters and buck inverter in Grid-Connected Photovoltaic Systems (original) (raw)
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2005
The present work describes the analysis, modeling and design of a power conditioning system for grid-connected photovoltaic (PV) systems. The designed power stage consists of a transformerless boost-buck converter. The power conditioning system's control scheme includes a variable structure controller to assure output unity power factor. To maximize the steady-state input-output energy transfer ratio a linear controller is designed out of a large-signal sampled data model of the system. The achievement of the DC-AC conversion and the efficient PV's energy extraction are validated with simulation results.
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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.
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.
2005
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This paper presents a recent technique for photovoltaic grid connected systems based on the use of the (DPC-SVM) to select the optimal switching states to apply to the inverter, where the extended reactive power is used instead of reactive power. This technique allows achieving an optimal control of the inverter which manifests in controlling the converters using an MPPT algorithm instead of controlling each part separately. This yields to a reduced global control system on a large scale. In this context, we suggest a DC-DC boost converter circuit to ensure better behavior of the system. The FMV technique is used to inject specific harmonics in order to eliminate or minimize the undesired harmonics. The SVM model has also been developed for optimal control of the inverter to prove the high performance of the proposed method. All the results are analyzed theoretically. The simulation has shown that this strategy gives satisfactory performances, improvement of the power factor and a r...
International Journal on Energy Conversion (IRECON), 2019
— This paper proposes the design and simulation of a DC-DC Boost converter employing PID controller, enhancing overall performance of the system. The main objective of a DC-DC converter is to maintain a constant output voltage despite variations in input/source voltage, components and load current. Designers aim to achieve better conversion efficiency, minimized harmonic distortion and improved power factor while keeping size and cost of converter within acceptable range. A simple PID (Proportional, Integral and Derivative) controller has been applied to a conventional Boost converter and tested in MATLAB-Simulink environment achieving improved voltage regulation. The proposed closed loop implementation of the converter maintains constant output voltage despite changes in input voltage and significantly reduces overshoot thereby improving the efficiency of the converter. The output of this investigation has the potential to contribute in a significant way in electric vehicles, industry, communication and renewable energy sectors.
Fast photovoltaic IncCond-MPPT and backstepping control, using DC-DC boost converter
International Journal of Electrical and Computer Engineering (IJECE), 2020
In this paper, we present our contribution in photovoltaic energy optimization subject. In this research work, the goal is to determinate fastly the optimal PV Module working point, allowing maximum power extraction. In this work we use DC-DC Boost converter to control the working point, by adjusting PV voltage trough duty cycle. In order to achieve our goal, we use the combination of incremental conductance MPPT technique and DC-DC Boost converter backstepping control. The validation of this control is made by Matlab simulation; the obtained results prove its effectiveness and its good maximum power tracking dynamics for different irradiance and temperature profiles.
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In this paper the design and the control of an individual PV (Photovoltaic) panel dc-ac converter based on a double coupled-inductors boost topology are discussed. The operation principle of the proposed circuit is analyzed. A proper calibration of the PV panel simulation model is performed. An optimization procedure is proposed for choosing the fundamental parameters of both converter and control law based upon sliding control technique. Furthermore, a Maximum Power Point Tracking (MPPT) approach based on a Perturb & Observe (P&O) algorithm is used to track the actual maximum power point through successive approximations. Finally, the proposed inverter is employed as a grid inverter in a single PV panel application. The numerical results reported in the paper permit to confirm the feasibility of the proposed design and control strategy.
TELKOMNIKA Telecommunication Computing Electronics and Control, 2020
A method of developing a maximum power point tracking (MPPT) algorithm for photovoltaic (PV) utilizing a peripheral interface controller (PIC) is presented in this paper. The efficiency and adequacy of a PV depend on the temperature and the exposed position to the sun. Thus, there is an optimum point at which the operating power is at maximum. The goal is to operate the PV module at this point (MPP). It can be accomplished by using the MPPT algorithm designed with a DC-DC boost converter. The boost converter, MPPT circuit, PIC18F4550 microcontroller and PV panel are the main components used in this design. The current and voltage produced by the solar panel are observed continuously by a closed-loop control system. The microcontroller-based control system adjusts the duty cycle of the converter to extract the maximum power. With a DC input voltage of 15 V, the boost converter is capable of generating an output voltage of an approximately 60 Vdc at a maximum power of 213.42 W with minimum voltage ripple as compared to 84 W without the MPPT. It proved the effectiveness of the developed algorithm.