Gird‐connected boost inverter for low‐power PV applications with model predictive control (original) (raw)
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Novel Predictive Maximum Power Point Tracking Techniques for Photovoltaic Applications
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A New Model Predictive Control Method for Buck-Boost Inverter-Based Photovoltaic Systems
Sustainability
This study designed a system consisting of a photovoltaic system and a DC-DC boost converter with buck-boost inverter. A multi-error method, based on model predictive control (MPC), is presented for control of the buck-boost inverter. Incremental conductivity and predictive control methods have also been used to track the maximum power of the photovoltaic system. Due to the fact that inverters are in the category of systems with fast dynamics, in this method, by first determining the system state space and its discrete time model, a switching algorithm is proposed to reduce the larger error for the converter. By using this control method, in addition to reducing the total harmonic distortion (THD), the inverter voltage reaches the set reference value at a high speed. To evaluate the performance of the proposed method, the dynamic performance of the converter at the reference voltage given to the system was investigated. The results of system performance in SIMULINK environment were ...
Many types of renewable energy, such as photovoltaic (PV), wind, tidal, and geothermal energy, have attracted a lot of attention over the past decade. Among these natural resources, the PV energy is a main and appropriate renewable energy for low-voltage dc-distribution systems, owing to the merits of clean, quiet, pollution free, and abundant. In the dc-distribution applications, a power system, including renewable distributed generators (DGS), dc loads (lighting, air conditioner, and electric vehicle), and a bidirectional inverter, is shown in fig. 1,in which two PV arrays with two maximum power point trackers (MPPTS) are implemented. However, the I–V characteristics of the PV arrays are nonlinear, and they require MPPTS to draw the maximum power from each PV array. Moreover, the bidirectional inverter has to fulfill grid connection (sell power) and rectification (buy power)with power-factor correction (PFC) to control the power flow between dc bus and ac grid,and to regulate the dc bus to a certain range of voltages, such as 380± 10 v.
A Predictive Control Scheme for Large-Scale Grid-Connected PV System Using High-Level NPC Inverter
Arabian Journal for Science and Engineering, 2019
This paper focuses on the control of large-scale grid-connected photovoltaic system. The proposed system is composed of two conversion stages: the first stage contains four PV arrays, each one connected to an individual DC/DC converter (boost converter), while the second stage is a five-level neutral point clamped (NPC) inverter tied to the grid. Each DC-link capacitor input of the NPC inverter is connected to the output of the DC/DC boost converter. In order to enhance the energy harvesting capability of the proposed system, different controllers based on finite-set model predictive control (FS-MPC) are developed and presented. A fast voltage-oriented maximum power point tracking performed by FS-MP current controller (FS-MPCC) is investigated and applied for each boost converter to maximize the produced power from each PV array. Furthermore, a FS-MPC algorithm is proposed to control the centralized five-level NPC inverter. The purposes of the developed controllers are: track the MPP rapidly and accurately under sudden irradiation changes, ensure the balance of the four DC-link capacitor voltages whatever the difference between the extracted powers from each PV system unit, inject the reactive power demanded by the grid operator and also minimize the switching frequency of the five-level NPC inverter. The results obtained through MATLAB/Simulink and Simpower toolbox packages prove that the proposed control scheme provides better performance in comparison with conventional control scheme. Moreover, a high grid current quality and perfect DC-link capacitor voltages balancing are ensured under contrast of extract powers from each PV system. Keywords Photovoltaic energy • Large-scale grid-connected PV systems • High-level NPC inverter • Voltage-oriented maximum power point (VO-MPPT) • Finite-set model predictive control (FS-MPC)
International Journal of Engineering Sciences & Research Technology, 2014
This paper proposes a topology for a transformer-less, pure sine wave grid-tie inverter (GTI) for photovoltaic (PV) application. The proposed GTI employs a dual-stage boost converter, a transformer-less step down circuit, an H-bridge inverter and a T-LCL Immittance conversion circuit. The switching technique of the proposed inverter consists of a combination of sinusoidal pulse width modulation (SPWM) and a square wave along with grid synchronizing conditions. As the suggested method is entirely transformer-less, it significantly reduces the total harmonic distortion (THD) of the output voltage (less than 0.1%), minimizes its size and swells the inverter efficiency up to 97%. The T-LCL Immittance conversion circuit not only reduces the harmonics of the inverter output but also provides a nearly constant output current thereby stabilizing the system rapidly. The overall performance of the proposed inverter is simulated using PSIM using the designed values of circuit components. The simulation results show that the proposed inverter is capable of not only eliminating harmonics but is also highly efficient, compact and cost effective.
Enhanced performance of PV power control using model predictive control
Solar Energy, 2017
This paper focuses on the use of model predictive control (MPC) to control a DC/DC boost converter in order to regulate the PV power. When integrated with the grid, the PV system must deliver maximum power most of the time; however, if a voltage sag occurs, new grid codes demand that the control system should limit the PV power generated to avoid over current conditions and, consequently, a grid disconnection. Maximum and reduced power modes are implemented following the MPC strategy to achieve high-performance and stable operation in the system. First, the system is modeled in Matlab/Simulink and PLECS to understand its operation and to evaluate the effectiveness of the proposed algorithm. Secondly, experimental results are verified using the control hardware-in-the-loop (CHIL) approach on the Real Time Digital Simulator (RTDS).
Power Loss Analysis of Solar Photovoltaic Integrated Model Predictive Control Based On-Grid Inverter
Energies
This paper presents a finite control-set model predictive control (FCS-MPC) based technique to reduce the switching loss and frequency of the on-grid PV inverter by incorporating a switching frequency term in the cost function of the model predictive control (MPC). In the proposed MPC, the control objectives (current and switching frequency) select an optimal switching state for the inverter by minimizing a predefined cost function. The two control objectives are combined with a weighting factor. A trade-off between the switching frequency (average) and total harmonic distortion (THD) of the current was utilized to determine the value of the weighting factor. The switching, conduction, and harmonic losses were determined at the selected value of the weighting factor for both the proposed and conventional FCS-MPC and compared. The system was simulated in MATLAB/Simulink, and a small-scale hardware prototype was built to realize the system and verify the proposal. Considering only 0.2...
Voltage Controlled Boost Converter-Inverter System for Photovoltaic Applications
2020
Photovoltaic electric energy generation systems are attractive for the places far from the electric grid system and for small scale applications. Off-grid inverters are widely used in renewable energy applications. Most of the applications such as home appliances require constant voltage. Thus, the voltage of the inverter needs to be kept constant. In this paper, the analysis, modelling, control and simulation of a photovoltaic module fed boost converter-inverter system is studied. The PV fed boost converter provides dc link for the inverter. The cascade connection of boost converter and an inverter provides sinusoidal voltage to the ac loads. A conventional proportional+integral (PI) controller is used to obtain a constant dc link voltage even with input voltage variations. Matlab-Simulink programming environment is used for the modelling and simulations. The simulation results are presented.
2016 IEEE Industry Applications Society Annual Meeting, 2016
This paper presents the concept of the three-phase module-integrated converters (MICs) incorporated in grid-tied large-scale photovoltaic (PV) systems. The current-source converter (CSC) with dc voltage boost capability, namely singlestage power conversion system, is proposed for three-phase PV MIC system. A model predictive scheme with low switching frequency is designed to control the proposed topology in such a way that provides a certain amount of active and reactive power in steady-state operation and also provides a proper ratio of reactive power under transient conditions to meet the low voltage ride through (LVRT) regulations. To predict the future behavior of current control values and switching states, a discrete-time model of the MIC is developed in synchronous reference frame. It is demonstrated that the injected active and reactive power can be controlled using minimizing the cost function introduced in the predictive switching algorithm. The proposed structure is simulated in MATLAB/SIMULINK software. An experimental verification is provided to justify the performance of the proposed control method through a 300-VA laboratory prototype. The results verify the desired performance of the proposed control scheme for exchanging of both active and reactive powers between the PV MIC and the grid within different operating conditions. Index Terms-Active and reactive control, current source converter (CSC), low voltage ride through (LVRT), moduleintegrated converter (MIC), model predictive control (MPC).