A novel approach to extract maximum power from partially shaded PV array
01 Oct 2015-pp 337-342
TL;DR: In this paper, a new approach to distribute the shading effect over the entire array to reduce the mismatch losses, and enhance the power output of a PV array is presented, where the physical position of the modules in the total cross-tied (TCT) configuration are arranged, without changing the electrical connection of the PV modules.
Abstract: The modules of a PV array receive different intensity of solar irradiation under partial shading condition and hence mismatch losses occurs between the modules. Multiple local maxima exist in the power-voltage characteristics of a PV array and out of multiple local maxima one of them is a global maximum power point (GMPP). This paper presents a new approach to distribute the shading effect over the entire array to reduce the mismatch losses, and enhance the power output of a PV array. In this approach, the physical position of the modules in the Total Cross Tied (TCT) configuration are arranged, without changing the electrical connection of the modules, and also the arrangement of the modules in the TCT configuration is done in such a way that, the shading effect is distributed over the entire array, and hence it reduces the multiple local maxima in power-voltage characteristics of a PV array. Thus the tracking of GMPP in the present approach is simpler. In this paper, the output power of a PV array estimated theoretically and by MATLAB simulation for the TCT and the proposed configuration is compared. It is investigated that, the power generation of a PV array with proposed configuration is improved compared to the TCT configuration under different shading patterns.
Citations
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TL;DR: In this paper, a simple and particularly efficacious maximum power point tracking (MPPT) algorithm based on Silver Mean Method (SMM) is proposed, which operates by choosing a search interval from the P-V characteristics of the given solar array and converges to MPP of the solar photo-voltaic (SPV) system by shrinking its interval.
Abstract: The proposed paper presents a simple and particularly efficacious Maximum Power Point Tracking (MPPT) algorithm based on Silver Mean Method (SMM). This method operates by choosing a search interval from the P-V characteristics of the given solar array and converges to MPP of the Solar Photo-Voltaic (SPV) system by shrinking its interval. After achieving the maximum power, the algorithm stops shrinking and maintains constant voltage until the next interval is decided. The tracking capability efficiency and performance analysis of the proposed algorithm are validated by the simulation and experimental results with a 100W solar panel for variable temperature and irradiance conditions. The results obtained confirm that even without any perturbation and observation process, the proposed method still outperforms the traditional perturb and observe (P&O) method by demonstrating far better steady state output, more accuracy and higher efficiency.
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References
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TL;DR: A novel algorithm to track the global power peak under partially shaded conditions and a feedforward control scheme for operating the DC-DC converter is proposed, which uses the reference voltage information from the tracking algorithm to shift the operation toward the MPP.
Abstract: Current-voltage and power-voltage characteristics of large photovoltaic (PV) arrays under partially shaded conditions are characterized by multiple steps and peaks. This makes the tracking of the actual maximum power point (MPP) [global peak (GP)] a difficult task. In addition, most of the existing schemes are unable to extract maximum power from the PV array under these conditions. This paper proposes a novel algorithm to track the global power peak under partially shaded conditions. The formulation of the algorithm is based on several critical observations made out of an extensive study of the PV characteristics and the behavior of the global and local peaks under partially shaded conditions. The proposed algorithm works in conjunction with a DC-DC converter to track the GP. In order to accelerate the tracking speed, a feedforward control scheme for operating the DC-DC converter is also proposed, which uses the reference voltage information from the tracking algorithm to shift the operation toward the MPP. The tracking time with this controller is about one-tenth as compared to a conventional controller. All the observations and conclusions, including simulation and experimental results, are presented.
906 citations
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TL;DR: In this paper, a novel MPPT method capable of RMPPT under partially shaded conditions (PSCs) is proposed, which is analyzed according to the RMPP position and verified by simulation and experimental results.
Abstract: Conventional popular maximum power point tracking (MPPT) methods are effective under uniform solar irradiance. However, under solar irradiance mismatching conditions [partially shaded conditions (PSCs)], these MPPTs can fail for real MPPT (RMPPT), because multiple local maxima can be exhibited on the power-voltage characteristic curve. Although some researchers have worked on RMPPT under partial shading conditions, the methods have some drawbacks in terms of complexity and requirements for additional circuits, etc. In this paper, a novel MPPT method capable of RMPPT under PSCs is proposed. The performance of the proposed MPPT method is analyzed according to the RMPP position and is verified by simulation and experimental results.
427 citations
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TL;DR: A dynamical electrical array reconfiguration strategy is applied on the photovoltaic generator of a grid-connected PV system based on a plant-oriented configuration in order to improve its energy production when the operating conditions of the solar panels are different.
Abstract: This paper applies a dynamical electrical array reconfiguration (EAR) strategy on the photovoltaic (PV) generator of a grid-connected PV system based on a plant-oriented configuration, in order to improve its energy production when the operating conditions of the solar panels are different. The EAR strategy is carried out by inserting a controllable switching matrix between the PV generator and the central inverter, which allows the electrical reconnection of the available PV modules. As a result, the PV system exhibits a self-capacity for real-time adaptation to the PV generator external operating conditions and improves the energy extraction of the system. Experimental results are provided to validate the proposed approach.
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TL;DR: A new method to track the global MPP is presented, which is based on controlling a dc/dc converter connected at the PV array output, such that it behaves as a constant input-power load.
Abstract: The power-voltage characteristic of photovoltaic (PV) arrays operating under partial-shading conditions exhibits multiple local maximum power points (MPPs). In this paper, a new method to track the global MPP is presented, which is based on controlling a dc/dc converter connected at the PV array output, such that it behaves as a constant input-power load. The proposed method has the advantage that it can be applied in either stand-alone or grid-connected PV systems comprising PV arrays with unknown electrical characteristics and does not require knowledge about the PV modules configuration within the PV array. The experimental results verify that the proposed global MPP method guarantees convergence to the global MPP under any partial-shading conditions. Compared with past-proposed methods, the global MPP tracking process is accomplished after far fewer PV array power perturbation steps.
384 citations
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TL;DR: This paper presents a maximum power point tracking approach for a photovoltaic system using the dividing rectangles algorithm, which is capable of searching for global maximum and possesses a fast tracking speed.
Abstract: This paper presents a maximum power point tracking approach for a photovoltaic system using the dividing rectangles algorithm. The new approach overcomes some weaknesses of the existing methods such as the perturb and observe method as it is capable of searching for global maximum. This is particularly important for a system that is partially shaded. To validate the performance of the proposed scheme, experimental studies have been conducted. The results have shown that the proposed approach is robust and possesses a fast tracking speed.
306 citations
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