Papers by Keyword: Partial Shading

Abstract: Under both typical and partial shading conditions, this research seeks to assess how two maximum power point tracking (MPPT) solutions, Perturb and Observe (P&O) and fuzzy logic control (FLC), help maximize power extraction from a photovoltaic (PV) system. Applying MATLAB SIMULINK, a DC-DC converter and a PV generator were simulated to run these MPPT systems. The comparison focuses on the extracted power, the performance of each technique, and their ability to follow the global maximum power point (MPP). The simulation findings show that in standard and partial shading conditions, both P&O and fuzzy logic algorithms can effectively track the MPP. The fuzzy logic controller, however, turned out to be more accurate and efficient (≥98% efficiency vs. P&O's 97%) with minimal power oscillation, while the P&O algorithm had a faster response time.

Abstract: The maximum power point extraction at any instant of time on photovoltaic (PV) systems has attracted attention. This study introduces a novel DC-DC converter-based power point tracking (PPT) algorithm for solar PV systems. The proposed optimization technique is a modified form of the standard particle swarm optimization (PSO), where the limitations of the standard PSO algorithm, like random number assignment of the acceleration factors and constant weight, are modified. The main goal of the suggested modified particle swarm optimization (MPSO) algorithm is to change the particle weight within a range of values and remove the random number from the acceleration factors. As a result, some of the contributions to this work are: First, when the weight is within some interval values, velocity restriction with a constant number improves. It offers the chance to expedite the search without limitation because of the constantly shifting environmental conditions. Second, the solution shows that the lack of acceleration constants predicts the particle's behavior. Thirdly, the algorithm's input parameters are incredibly minimal. The MATLAB/Simulink simulation of a modeled standalone 2.9 kW solar PV system in shading and non-shading conditions proved the proposed algorithm's performance. Thus, the average efficiency and time tracking of the global maximum power point (GMPP) is 99.45% and 6.285 s, respectively. Generally, the proposed MPPT method is more straightforward and adaptable than perturb and observe (P&O), the cuckoo search algorithm, and standard PSO.

Abstract: Multiple local maxima (MPPs) are presented on the P-V curve of a PV system under partial shading conditions. In general, standard maximum power point tracking (MPPT) algorithms have trouble locating the global maximum, leading often to suboptimal operation at a local MPP, and thus to decreased efficiency. In commercial inverters, this situation is mitigated by performing periodically scans of the characteristic curve to relocate the global MPP. However, this procedure entails fluctuation of the power output, as well as, short-term power losses. To limit these implications, a simple algorithm is introduced in this paper, which mathematically determines whether a PV system is partially shaded or not, thus avoiding unnecessary curve scans at uniform illumination. The proposed method needs only datasheet information and a temperature sensor, while it is applicable to any PV topology, multiple irradiance levels and is readily implemented as an enhancement to any existing MPPT algorithm.

Abstract: Partial shading is the major contributing factor for reduced energy harvest in building integrated or rooftop photovoltaic (PV) systems. The architecture of the PV array is altered dynamically in accordance with shade intensity to alleviate the impact of partial shading. However, this technique demands more number of sensors, switches and a sophisticated control algorithm. In small urban residential installations, the shade is often caused by trees and structures in the same or nearby buildings and is inevitable due to space limitations. The shape and intensity of the shade does not vary rapidly in these cases and hence dynamic reconfiguration is not necessary. The paper addresses the issue by proposing a simple tailored architecture to enhance the output under shaded conditions without using additional sensors and switches. The location of the panels in an array is predetermined in the proposed work in such a way that the shade is evenly distributed all over the array. This reduces the mismatch losses and enhances the output. For utility purposes, asymmetric multilevel inverter controlled by FPGA (Field Programmable Gate Array) is employed and the results are presented.

Abstract: This paper presents the investigation of partial shading characteristics of mono-crystalline and poly-crystalline photovoltaic module connected in series. Simulink models are developed to assist the investigation to determine the ideality factor for mono-crystalline and poly-crystalline photovoltaic module. Commercially available mono-crystalline and poly-crystalline photovoltaic module are used to extract measurable parameters for the model to study the behaviour of I-V curve. Measurements have been conducted for the investigation including mono-crystalline only, poly-crystalline only, both unshaded, mono-crystalline shaded and poly-crystalline shaded. This paper contributes to the understanding of partial shading characteristics of different materials presence in photovoltaic string.

Abstract: The impact of partial shading on photovoltaic (PV) array is discussed in this paper. The partial shading on PV array can significantly decrease the power generation of PV array. This study examines the modeling of PV module which relates with solar irradiation, temperature, and shading pattern. There are different shading patterns on PV array, such as one-string shading, two-strings shading, and much more. The characteristics of current-voltage (I-V) and voltage-power (V-P) curves for each individual the PV array can be different dependent on the multiple MPPs, maximum power points (MPPs). These multiple MPPs are basically lower than the MPP in case of no shading. Therefore, the total generated energy in an interested time period is usually reduced. As a result, this paper proposes the appropriate arrangement of PV modules in a PV array in order to mitigate the impact of partial shading. Finally, the proposed arrangement of PV modules is tested in a testing system. All the obtained results confirms that the proposed arrangement of PV modules is effective and can be applied in practice.

Abstract: This paper discuss about the effect of partial shading on photovoltaic array and driving the dc-dc boost converter to track maximum power point (MPP ) by incremental conductance (INC) MPPT algorithm. The temperature, irradiance, shading and array configuration will greatly affect the Photovoltaic performance. The shading effect on photovoltaic panel are caused by passing clouds ,neighbouring trees, neighbouring buildings ,towers .The PV characteristic of Photovoltaic panel get more complex under partial shading condition. The P-V and I-V characteristic under nonuniform insolation are simulated in Matlab based on solar irradiance and cell temperature. The design and analysis are made simple and easy through Simscape package.

Abstract: The efficiency of building integrated photovoltaic (PV) system is greatly affected by the partial shaded conditions. The impact of shading conditions depends not only on the level of shading but also on other factors like array size, type of configuration adopted, pattern and intensity of the shade. The influence of partial shading is much pronounced in series configuration than any other types due to the absence of cross ties. Unless protected by bypass diodes, the thermal stress across the panel increases under shaded conditions and eventually leads to the development of hot spots that can damage the shaded panel permanently. Bypass diode totally isolates the shaded panel from the rest of the of the array leaving the array underutilized. To address this issue, this paper proposes repositioning of the panels to distribute the shade uniformly all over the array. Besides, a hybrid asymmetric multilevel inverter is proposed for power conversion.

Abstract: The power generated by solar photovoltaic system depends on insolation, temperature and shading situation etc. These days’ solar PV arrays are mainly building integrated. Therefore PV array are often under partial shadow. The feature of these shadows can be either easy-to-predict (like neighbour’s chimney, nearby tree or neighbouring buildings) or difficult-to-predict (passing clouds, birds litter).Thus output power obtained by PV arrays decreases in a considerable manner. In this paper, output powers, currents and voltages for SP & TCT topologies are calculated for different patterns of easy-to-predict partial shading conditions on a 4×4 PV field.

Abstract: In photovoltaic (PV) power generation systems, the P-V curve of PV array contains several peaks under partially shaded condition (PSC) so that conventional MPP tracking (MPPT) methods can hardly find the real MPP (MPP). This paper proposes an optimized MPPT strategy, which is not only fit for PSC but also suitable for uniform shaded conditions (USC). Comparing the optimized MPPT strategies and conventional MPPT methods, this paper illustrates the improved performance of optimized strategy under PSC. The simulation and experiment results show that the optimized strategy can track the global MPP precisely to improve the efficiency of PV systems.