Proposed Reconfiguration Technique Research Articles

Enhancement of power output of partially shaded photovoltaic system using optimal Sudoku puzzle based triple-tied-cross-link reconfiguration techniques

Partial shade on a photovoltaic (PV) array reduces output power because of mismatch losses. Therefore, selection of PV array configuration is one of the crucial factors to consider for maximum power output. The Triple-Tied-Cross-Link (TTCL) configuration used has lesser tied connection in contrast to the conventional Total-Cross-Tied (TCT) configuration. The performance oSf the TTCL configuration is further enhanced by applying Sudoku puzzles as a reconfiguration technique. Without changing the electrical connection, the Sudoku puzzle is used to arrange the physical placement of the modules in the PV arrays. By dispersing the shading impact over the array, the suggested arrangement reduces the amount of shade that dominates in any one row. The recommended Optimal Sudoku Puzzle (OSP)- based TTCL design’s performance has been compared to the TTCL setup for the 9 × 9 PV array. Six partial shading patterns named Group-I to Group-VI are considered to analyze the performance of the proposed reconfiguration technique. The number of parameters such as global maximum power point (GMPP), open circuit voltage, short circuit current, mismatch loss, fill factor, and efficiency are measured to show its performance under different shading patterns. The numerical results show the effectiveness of the recommended OSP- based TTCL configuration technique. It is investigated that the numerical values in the case of shading pattern Group-III for the performance parameter GMP and fill factor have increased by 11.59% and 16.90 %, respectively, as compared to TTCL configuration. The mismatch loss (ML) was achieved with the lowest value, i.e., 21.98%, when compared to the TTCL (36.13%). The 9 × 9 PV array’s efficiency in the proposed configuration is 13.33%, which is higher than that of TTCL (11.94%) arrangements. From the simulated results, the puzzle-based reconfiguration technique is found to be an optimal approach as compared to traditional configuration.

One-step adaptive reconfiguration technique for partial shaded photovoltaic array

The performance of a photovoltaic (PV) array greatly depends on partial shading conditions, which can be diminished by careful planning and positioning of PV modules during installation to avoid self-shading. However, partial shading caused by nearby buildings, dust, and snow cannot be completely avoided. One of the approaches to reduce the effects of partial shading is the reconfiguration technique. However, the reconfiguration increases the length of the wire and system complexity. This study proposes an adaptive reconfiguration technique for a 4x4 PV array with reduced complexity and better shade dispersion. The effectiveness of the proposed reconfiguration technique is implemented and tested on a 4x4 total-cross-tied PV array in a MATLAB Simulink environment. In the proposed configuration, the switching matrix connects the fixed and adaptive part of the PV array, in such a way that the switches can connect the PV module of the next column by shifting downwards and shifting upwards. A comprehensive analysis of proposed reconfiguration is carried out and its performance is compared with existing fixed and dynamic reconfiguration techniques in terms of performance parameters. The study result shows that the proposed reconfiguration technique delivers superior performance compared to existing fixed and dynamic reconfiguration techniques in terms of better shade dispersion, enhanced performance and reduced complexity. For the LC shade pattern, the proposed BSSU technique has obtained improved PE of 48%, 31%, 15% and 9% compared to CMA, TCT, ADR and SS configurations. Experimental verification is carried out to demonstrate the superiority of the proposed reconfiguration technique.

A novel PV array reconfiguration technique based on circular array data structure

Partial shading condition (PSC) poses a significant challenge to solar power generation as it has a severe impact on the performance of photovoltaic (PV) systems, leading to a decrease in energy yield and reliability. Reconfiguration of PV arrays is a potential technique to deal with this challenge, however, reconfiguration techniques proposed in the past are restricted in their suitability for practical implementations in real-world installations as they are only optimal for specific shading patterns. To overcome this limitation, the article introduces a novel reconfiguration approach inspired by the circular array data structure, a commonly utilized tool in the realm of computer science. The proposed circular array transformation (CAT) technique shows great potential in mitigating the impact of partial shading (PS) and maximizing the overall power generation across a wider range of PSCs. The effectiveness of the proposed technique is validated through simulations and experimental studies conducted on a 5 × 5 PV array. Furthermore, the scalability of the proposed reconfiguration technique is verified through extensive simulations on a 9 × 9 PV array. Comparative analysis reveals that the proposed CAT rearrangement approach exhibits clear dominance and outperforms existing and recently published state-of-the-art reconfiguration methods.

A Novel Solar Photovoltaic Array Reconfiguration Technique Using Two-Dimensional Generalized Arnold's Cat Map

Abstract This paper presents a highly efficient image encryption-based Arnold's cat map (ACM) technique to reconfigure the photovoltaic (PV) array to enhance the output and mitigate the mismatch losses due to partial shading (PS). The proposed ACM technique concentrates on alleviating the power loss by effectively dispersing the shade over the entire PV array without modifying its electrical circuitry. The proposed reconfiguration technique is investigated and analyzed with conventional series–parallel and total-cross-tied configurations along with the recently reported chaotic Baker's map, odd–even, odd–even–prime pattern-based configurations. The proposed technique is examined for symmetrical 6 × 6 PV array and unsymmetrical 6 × 9 PV array under distinct nonuniform and uniform PS cases. To confirm the potency and superior performance of the proposed technique, the system has been extensively examined with nine performance parameters such as global maximum power, mismatch power, power loss, efficiency, fill factor, array yield, capacity factor, performance ratio, and the number of maximum power peaks. An experimental setup of a 4 × 4 array reconfiguration system prototype is developed and tested in a real-time environment to validate the effectiveness of the proposed technique over the existing ones. From the comprehensive investigation, it is regarded that the proposed technique offers consistently superior performance with the least percentage mismatch losses and maximum power enhancement of 48.8%, 31.03%, and 27.5% for various shading cases of 6 × 6 and 6 × 9 PV arrays.

Maximization of photo-voltaic array power output through Lo Sho Square shade dispersion technique based re-configuration scheme

Non-homogenous irradiation levels across the solar PV array reduces the overall power yield of solar PV plant. Therefore, it is essential to decrease mismatch power loss incurred under non-homogenous conditions. For this purpose, ‘Lo Sho Square’ shade dispersion technique based re-configuration of solar PV modules is investigated in the present research work. Proposed ‘Lo Sho Square’ shade dispersion technique effectively scatters the non-homogenous irradiation across the reconfigured solar PV array, rather than concentrated on one location. Performance of the proposed re-configuration technique is studied by subjecting the 9 × 9 sized solar PV array under five different categories of non-uniform irradiation conditions. Efficacy of the proposed re-configuration is justified to be superior by comparing the simulation results obtained from proposed ‘Lo Sho Square’ technique with those obtained for Total-Cross-Tied interconnection and four recently reported ‘Normal SU-DO-KU’, ‘Optimized SU-DO-KU’, ‘Improved SU-DO-KU’ and ‘Modified SU-DO-KU’ shade dispersion techniques. The simulation results indicate that the proposed re-configuration scheme with values of 20%, 12.5%, 12.5%, 16.13% and 12.5% under five categories of typical non-homogenous conditions, has the lowest mismatch power loss relatively compared to that of literature reported four shade dispersion techniques. In addition, the proposed ‘Lo Sho Square’ technique based re-configuration with the efficiency values of 14.18%, 15.12%, 15.12%, 14.65% and 15.12% under five categories of typical non-homogenous conditions, has highest efficiency relatively compared to literature reported four shade dispersion techniques. Based on the comparative analysis of results obtained upon five typical non-homogeneous conditions, it is concluded that proposed ‘Lo Sho Square’ shade dispersion technique provides a relatively superior output performance compared to that of ‘Normal SU-DO-KU’, ‘Optimized SU-DO-KU’, ‘Improved SU-DO-KU’ and ‘Modified SU-DO-KU’ techniques.

Performance and Reliability Improvement of Partially Shaded PV Arrays by One-Time Electrical Reconfiguration

Partial shading is the most unexpected scenario encountered by the arrays that degrade the performance causing power reduction, non-convex characteristics curves, losses, hotspot, module damage, and system failure. The adoption of various reconfiguration techniques has recently provided relief to the PV array to reduce power losses during partial shading. However, these techniques exhibit vulnerabilities such as reliable operation, ease of implementation and, higher cost and complexity due to the requirement of abundant manpower, labour, complex algorithms, dynamic operation, switches and sensors that cause additional power losses. Hence, this paper presents a low cost and less complex reconfiguration technique for PV arrays to effectively increase the power generation during partial shading scenarios. The proposed reconfiguration does not require any manpower, labour, algorithms or additional devices to reduce the losses in arrays during shading. The efficacy of the technique is tested using two array sizes under various shading scenarios using MATLAB modelling and real-time field experiments. Also, for better analysis, the performance of the proposed technique is compared with conventional configurations and Sudoku reconfiguration. The investigation proclaimed that the proposed reconfiguration technique has an average power enhancement of 20% higher than any other conventional configurations.

Enhanced energy harvesting from rooftop PV array using Block Swap algorithm

Partial Shading conditions arising from tall buildings, upcoming infrastructural setup, trees, passing clouds, and other factors adversely affect the Photo-Voltaic (PV) array output power and overall efficiency. This paper proposes a field implementable PV array reconfiguration technique named Block Swap-inspired Fixed Column (BSFC) reconfiguration. The proposed reconfiguration technique makes one-time connections (at the time of PV array installation). It eliminates the need to physically relocate the PV panel as is propounded by various static and dynamic reconfiguration techniques reported in the literature. The physical relocation of PV panels is not a viable real-time solution for shade dispersion due to the shading patterns' stochastic nature. The proposed technique works well for both square (m × m) and non-square matrix (m × n) dimensions of the PV array and provides better results for all shading patterns witnessed over the length of the day. The effectiveness and feasibility of the proposed reconfiguration technique (BSFC) are tested on a solar PV rooftop array installed at IIT Jammu Campus, and the simulation is done on the MATLAB platform. Simulation results confirm the potential and effectiveness of BSFC after comparison with other reconfiguration methods like Series-Parallel (SP), Total Cross Tied (TCT), Odd-Even (OE), Odd-Even Prime (OEP). The proposed technique provides enhanced power output while utilizing the least length of the connecting dc cables and the least electrical displacement w.r.t initial electrical connections. BSFC technique applies to any string length of the PV array without additional support circuitry and results in lower voltage drops across the length of the dc cable.

Comparative analysis of two-step GA-based PV array reconfiguration technique and other reconfiguration techniques

Photovoltaic (PV) plants can be exposed to partial shading, which reduces the energy production and causes multi-peaks to form in the Power-Voltage (P-V) curve. As a result, the row currents of the PV modules will not be constant. Several techniques have been proposed to overcome partial shading, such as the static and dynamic reconfiguration techniques, with both aiming to reduce the difference in the row currents to improve energy production. Minimization of the row current via static techniques requires laborious work and extra wiring. On the other hand, dynamic techniques require an extensive monitoring system to support different tasks. Therefore, to improve the power generated from the PV array, this paper suggests a new reconfiguration technique for PV panels using Genetic algorithm (GA) and two main reconfigurable steps based on a switching matrix. In this technique, only the electrical connections of the PV panels are changed while its physical location remains unchanged. To verify the effectiveness of the proposed reconfiguration technique, the system was simulated and tested using MATLAB/SIMULINK software, with four shading patterns. The results were compared with other reconfiguration techniques, namely TCT configuration, competence square (CS), SuDoKu, two-phase array reconfiguration, Genetic algorithm (GA), Particle Swarm Optimization (PSO), and Modified Harris Hawks Optimization (MHHO). The performance of each shading case was also analyzed. Also, a comparative study on performance analysis in real-time application was carried out for each shading pattern. The results prove the superiority of the proposed technique over other techniques for overcoming partial shading.

Solar PV array reconfiguration using the concept of Standard deviation and Genetic Algorithm

Partial shading of PV arrays is one of the most discussed and worked upon problem in the field of solar photovoltaic as it reduces the output power and exhibits multiple peaks in the PV and IV characteristics. As, a result the modules have to be reconfigured to get a maximum power output. This paper presents an optimization based approach for Total cross tied (TCT) connected modules in a PV array. The physical locations of the modules remain unchanged while the electrical connections are altered. The proposed technique utilizes, standard deviation genetic algorithm (SDGA) as an optimization tool, which gives the final connection matrix for the new electrical interconnection which extracts the maximum power from the PV array. This is done to obtain uniform shade dispersion throughout the panel. The proposed method has been tested and simulated in Matlab-Simulink environment under partial shading conditions. Results of the simulation show that the proposed reconfiguration technique exhibit superior results as compared to the traditional TCT interconnection scheme.

A High-Linearity Low-Noise Reconfiguration-Based Programmable Gain Amplifier

This paper presents a high-linearity low-noise small-size programmable gain amplifier (PGA) based on a new low-noise low-distortion differential amplifier and a proposed reconfiguration technique. The proposed differential amplifier combines an inverter-based differential pair with an adaptive biasing circuit to reduce noise and distortion. The reconfiguration technique saves the chip size by half by utilizing the same differential pair for the input transconductance and load-stage, interchangeably. Fabricated in 0.18- ㎛ CMOS, the proposed PGA shows a dB-linear control range of 21dB in 16 steps from-11dB to 10 dB with a gain error of less than ±0.33 dB, an IIP3 of 7.4~14.5 dBm, a P1dB of -7~1.2 dBm, a noise figure of 13dB, and a 3-dB bandwidth of 270㎒ at the maximum gain, respectively. The PGA occupies a chip area of 0.04㎟ and consumes only 1.3㎃ from the 1.8V supply.

선박 백본 네트워크의 논리 토폴로지 재구성 기법

본 논문에서는 연속적인 트래픽 요구 변화에 대처할 수 있는 선박 백본 네트워크의 논리 토폴로지 재구성 방안을 연구하였다. 제안한 기법은 트래픽 포워딩 경로의 변경을 최소화하며, 동시에 트래픽 포워딩 경로의 평균 홉 수를 최소화하여 선박 백본 네트워크의 성능을 향상시킨다. 제안한 재구성 기법의 성능 분석을 수행한 결과, 연속적인 재구성 처리 과정에서 우수한 성능을 보여 주었다. This paper studies a series of logical topology reconfiguration processes corresponding to a series of traffic demand changes in a ship backbone network. The proposed reconfiguration technique is to minimize costly changes of traffic forwarding paths and minimize the average hop distance of traffic forwarding paths in terms of ship backbone network performance simultaneously. Performance evaluation is conducted to illustrate the efficiency of the proposed reconfiguration technique. It shows that the proposed reconfiguration technique yields efficient performance in the entire series of reconfiguration processes.

High-Resolution ADC Linearity Testing Using a Fully Digital-Compatible BIST Strategy

This paper proposes a digital-compatible built-in self-test (BIST) strategy for high-resolution analog-to-digital converter (ADC) linearity testing using only digital testing environments. The on-chip stimulus generator consists of three low-resolution and low-accuracy current steering digital-to-analog converters (DACs), which are area efficient and easy to design. The linearity of the stimuli is improved by the proposed reconfiguration technique. ADCs' outputs are evaluated by simple digital logic circuits to characterize the nonlinearities. The proposed BIST strategy is capable of characterizing ADC transition levels one by one with small hardware overhead. The testing performance is not sensitive to the mismatches and process variations, so that the analog BIST circuits can easily be reused without complex self-calibration. Simulation and experimental results show that the proposed circuitry and BIST strategy can test the INL <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> error of 12-bit ADCs to a plusmn0.15 least significant bit (LSB) accuracy level using only 7-bit linear DACs.

An efficient technique for a series of virtual topology reconfigurations in WDM optical networks

This paper studies a series of reconfiguration processes corresponding to a series of traffic demand changes in WDM optical networks. This study describes the reconfiguration problem from two perspectives. First, the reconfiguration problem is a multi-optimization problem such that a single-objective optimization method could not be applied. Second, the reconfiguration problem consists of a series of reconfiguration processes for given traffic demand changes. The current virtual topology optimally generated for a given traffic demand change may lead to the costly disruption of traffic routing to adapt a new traffic demand change because it is independent of the next traffic demand change. Since the reconfiguration process that considers the only current traffic demand cannot guarantee the optimal average outcome in the long term, sequential decision-making is required to optimize the average outcome from the entire series of reconfiguration processes. The proposed reconfiguration technique is to minimize costly changes of lightpath routing changes in terms of network cost and minimize the average hop distance of traffic in terms of network performance simultaneously. Since the objective goal of maximizing network performance conflicts with that of minimizing network cost, there exists a set of non-dominated solutions called the Pareto front. The reconfiguration technique includes a reconfiguration process and a reconfiguration policy. The reconfiguration process finds a set of non-dominated solutions using the PEAP (Pareto Evolutionary Algorithm adapting the Penalty method) that optimizes objective functions by using the concept of Pareto optimal. Then, reconfiguration policy picks a solution from the set of non-dominated solutions using the MDA (Markov Decision Action). A case study based on simulation experiments is conducted to illustrate the application and efficiency of the proposed technique. It shows that our reconfiguration technique incorporating the PEAP and the MDA yields efficient performance in the entire series of reconfiguration processes.

Design of reconfigurable fault-tolerant VLSI/WSI processor array structures

This paper presents a new reconfiguration technique for VLSI/WSI processor arrays. The fault-tolerant capabilities of both interstitial redundancy and time redundancy are combined to provide optimal reconfiguration. Results obtained through Monte Carlo simulations show that with the proposed reconfiguration technique, a very high yield and chip area utilization is achieved. It is also shown that in the presence of harsh environments, where a high rate of transient faults occur, the proposed algorithm is more robust compared to the existing approaches.