Probabilistic Global Maximum Power Point Tracking Algorithm for Continuously Varying Partial Shading Conditions on Autonomous PV Systems

A photovoltaic (PV) string with multiple modules with bypass diodes frequently deployed on a variety of autonomous PV systems may present multiple power peaks under uneven shading. For optimal solar harvesting, there is a need for a control schema to force the PV string to operate at global maximum power point (GMPP). While a lot of tracking methods have been proposed in the literature, they are usually complex and do not fully take advantage of the available characteristics of the PV array. This work highlights how the voltage at operating point and the forward voltage of the bypass diode are considered to design a global maximum power point tracking (GMPPT) algorithm with a very limited global search phase called Fast GMPPT. This algorithm successfully tracks GMPP between 94% and 98% of the time under a theoretical evaluation. It is then compared against Perturb and Observe, Deterministic Particle Swarm Optimization, and Grey Wolf Optimization under a sequence of irradiance steps as well as a power-over-voltage characteristics profile that mimics the electrical characteristics of a PV string under varying partial shading conditions. Overall, the simulation with the sequence of irradiance steps shows that while Fast GMPPT does not have the best convergence time, it has an excellent convergence rate as well as causes the least amount of power loss during the global search phase. Experimental test under varying partial shading conditions shows that while the GMPPT proposal is simple and lightweight, it is very performant under a wide range of dynamically varying partial shading conditions and boasts the best energy efficiency (94.74%) out of the 4 tested algorithms.

A New Flower Pollination Algorithm Strategy for MPPT of Partially Shaded Photovoltaic Arrays

Photovoltaic(PV)systems utilize maximum power point tracking(MPPT)controllers to optimize power output amidst varying environmental conditions.However,the presence of multiple peaks resulting from partial shading poses a challenge to the tracking operation.Under partial shade conditions,the global maximum power point(GMPP)may be missed by most traditional maximum power point tracker.The flower pollination algorithm(FPA)and particle swarm optimization(PSO)are two examples of metaheuristic techniques that can be used to solve the issue of failing to track the GMPP.This paper discusses and resolves all issues associated with using the standard FPA method as the MPPT for PV systems.The first issue is that the initial values of pollen are determined randomly at first,which can lead to premature convergence.To minimize the convergence time and enhance the possibility of detecting the GMPP,the initial pollen values were modified so that they were near the expected peak positions.Secondly,in the modified FPA,population fitness and switch probability values both influence swapping between two-mode optimization,which may improve the flower pollination algorithm’s tracking speed.The performance of the modified flower pollination algorithm(MFPA)is assessed through a comparison with the perturb and observe(P&O)method and the standard FPA method.The simulation results reveal that under different partial shading conditions,the tracking time for MFPA is 0.24,0.24,0.22,and 0.23 s,while for FPA,it is 0.4,0.35,0.45,and 0.37 s.Additionally,the simulation results demonstrate that MFPA achieves higher MPPT efficiency in the same four partial shading conditions,with values of 99.98%,99.90%,99.93%,and 99.26%,compared to FPA with MPPT efficiencies of 99.93%,99.88%,99.91%,and 99.18%.Based on the findings from simulations,the proposed method effectively and accurately tracks the GMPP across a diverse set of environmental conditions.

Electrical Power Losses in a Photovoltaic Solar Cell Operating under Partial Shading Conditions

The aim of this paper is to determine the power losses recorded by a PV generator operating under partial shading conditions. These losses are evaluated through two distinct methods. The first method is based on mathematical modeling, while the second is based on Simulink’s physical model. The losses recorded are considerable and increase as a function of the increase in the percentage of shading up to a limit value where they become constant in the case where an ideal by-pass diode is connected in parallel with the modules. This limit value is non-existent in the case where the bypass diode is not ideal, which in fact corresponds to the real model. However, it emerges that the power losses are minimized in a PV system comprising bypass diodes, in particular in the case where the partial shading is considerable.

A Novel Aquila Optimizer Based PV Array Reconfiguration Scheme to Generate Maximum Energy under Partial Shading Condition

This paper develops a real-time PV arrays maximum power harvesting scheme under partial shading condition(PSC)by reconfiguring PV arrays using Aquila optimizer(AO).AO is based on the natural behaviors of Aquila in capturing prey,which can choose the best hunting mechanism ingeniously and quickly by balancing the local exploitation and global exploration via four hunting methods of Aquila:choosing the searching area through high soar with the vertical stoop,exploring in different searching spaces through contour flight with quick glide attack,exploiting in convergence searching space through low flight with slow attack,and swooping through walk and grabbing prey.In general,PV arrays reconfiguration is a problem of discrete optimization,thus a series of discrete operations are adopted in AO to enhance its optimization performance.Simulation results based on 10 cases under PSCs show that the mismatched power loss obtained by AO is the smallest compared with genetic algorithm,particle swarm optimization,ant colony algorithm,grasshopper optimization algorithm,and butterfly optimization algorithm,which reduced by 4.34%against butterfly optimization algorithm.

Development of Hybrid MPPT Algorithm for Maximum Power Harvesting under Partial Shading Conditions

In this paper, a Hybrid MPPT algorithm is proposed to improve the efficiency of photovoltaic (PV) systems under partial shading conditions. Partial shading occurs due to clouds, trees, dirt and dust in PV systems. In partial shading, multiple peaks arise in the PV characteristic curve. The Maximum power point tracking (MPPT) algorithm adjusts the duty cycle of the switch in DC-DC converter for regulating the input voltage at the Maximum power point (MPP) and to provide impedance matching i.e. input resistance of converter equal to equivalent solar resistance of PV system at MPP for the maximum power transfer. The Cuk converters have low switching losses and the highest efficiency. Therefore Cuk converter is chosen as power conditioning circuit to trackmaximum power using Hybrid MPPT technique. The influence of algorithm parameters on system behaviour is investigated and the various advantages and drawbacks of the technique are identified for different weather conditions. Practical results obtained using Solartech SPMO85P PV modules connected to a RL load through Hybrid MPPT controller validates the simulated results.

State-of-the-art review of MPPT techniques for hybrid PV-TEG systems:modeling,methodologies,and perspectives

The development of alternative renewable energy technologies is crucial for alleviating climate change and promoting energy transformation.Of the currently available technologies,solar energy has promising application prospects owing to its merits of being clean,safe,and sustainable.Solar energy is converted into electricity through photovoltaic(PV)cells;however,the overall conversion efficiency of PV modules is relatively low,and most of the captured solar energy is dissipated in the form of heat.This not only reduces the power generation efficiency of solar cells but may also have a negative impact on the electrical parameters of PV modules and the service life of PV cells.To overcome the shortcomings,an efficient approach involves combining a PV cell with a thermoelectric generator(TEG)to form hybrid PV-TEG systems,which simultaneously improve the energy conversion efficiency of the PV system by reducing the operating temperature of the PV modules and increasing the power output by utilizing the waste heat generated from the PV system to generate electricity via the TEGs.Based on a thorough examination of the literature,this study comprehensively reviews 14 maximum power point tracking(MPPT)algorithms currently applied to hybrid PV-TEG systems and classifies them into five major categories for further discussion,namely conventional,mathematics-based,metaheuristic,artificial intelligence,and other algorithms.This review aims to inspire advanced ideas and research on MPPT algorithms for hybrid PV-TEG systems.

Research on the MPPT of Photovoltaic Power Generation Based on the CSA-INC Algorithm

The existing Maximum Power Point Tracking(MPPT)method has low tracking efficiency and poor stability.It is easy to fall into the Local Maximum Power Point(LMPP)in Partial Shading Condition(PSC),resulting in the degradation of output power quality and efficiency.It was found that various bio-inspired MPPT based optimization algorithms employ different mechanisms,and their performance in tracking the Global Maximum Power Point(GMPP)varies.Thus,a Cuckoo search algorithm(CSA)combined with the Incremental conductance Algorithm(INC)is proposed(CSA-INC)is put forward for the MPPT method of photovoltaic power generation.The method can improve the tracking speed by more than 52%compared with the traditional Cuckoo Search Algorithm(CSA),and the results of the study using this algorithm are compared with the popular Particle Swarm Optimization(PSO)and the Gravitational Search Algorithm(GSA).CSA-INC has an average tracking efficiency of 99.99%and an average tracking time of 0.19 s when tracking the GMPP,which improves PV power generation’s efficiency and power quality.

A Robust Single-Sensor MPPT Strategy for Shaded Photovoltaic-Battery System

A robust single-sensor global maximum power point tracking(MPPT)strategy based on modern optimization for photovoltaic systems considering shading conditions is proposed in this work.The proposed strategy is designed for battery charging applications and direct current(DC)microgrids.Under normal operation,the curve of photovoltaic(PV)output power versus PV voltage contains only a single peak point.This point can be simply captured using any traditional tracking method like perturb and observe.However,this situation is completely different during the shadowing effect where several peaks appear on the power voltage curve.Most of these peaks are local with only a single global.This condition leads to the incapability of traditional tracking approaches to extract the global peak power due to their inability to distinguish between the local and global peak points.They are trapped in the first peak point even when the point is local.Therefore,global tracking approaches based on modern optimization are highly required.A recent marine predators algorithm(MPA)has been used to solve the problem of tracking the global MPP under shadowing influence.Different shadowing scenarios are used to test and evaluate the performance of MPA based tracker.The obtained results are compared with particle swarm optimization(PSO)and ant lion optimizer(ALO).The results of the comparison con-firmed the effectiveness and robustness of the proposed global MPPT-MPA based tracker over PSO and ALO.

Experimental Analysis to Extract the Maximum Output of Serial and Parallel PV Module Configurations under Partial Shadow Conditions: A Case Study for Bambey, Senegal

Using an experimental setup, the series configurations (SC) and the parallel configurations (PC) of the PV cell connection are studied to compare their performance under the condition of partial shading s. The performance of the configurations is evaluated by comparing the open-circuit voltage, the short-circuit current, the maximum power point (MPP), the voltage and current corresponding to MPP, and the Fill Factor (FF). The variations of the series resistance and the shunt resistance of a PV module under different irradiance levels are also determined by considering the effect of thermal voltage. Finally, a comparison between the performance losses in the different configurations is presented. The results of this study show that the parallel configuration has the best performance under the conditions of partial shade in the context of this work.

A novel reconfiguration of the solar array to enhance peak power and efficiency under partial shading conditions:experimental validation

Non-homogeneous irradiation patterns and temperature levels immensely affect the performance of solar photovoltaic arrays.Partial shading conditions on solar arrays reduce the peak power and efficiency.This paper provides a new remedy called a novel Ramanujan reconfiguration(NRR)to eliminate this physical shading problem in solar photovoltaic systems.NRR is a static-based reconfigured technique that is built using a three-diode model with the help of the MATLAB®/Simulink®tool.The special feature of the proposed NRR technique is that when shade occurs on the solar modules,it gets realigned in a particular row,column,diagonal,corner,centre and middle peripheral cages.This helps over a wide range of shade dispersion on the solar array.The novel topology is tested against the conventional total cross-tied(TCT)model and recently introduced advanced reconfigured models,namely odd–even topology(OET)and Kendoku topology(KDT).The results are tested under certain shading conditions.The proposed NRR technique increases the peak power by 4.45,2.15 and 2.17 W under the first shading condition regarding TCT,OET and KDT.Its efficiency is improved by 0.51–2.18%under the third shading condition compared with other considered models in this study.In addition,NRR leads to smooth output curves under the second,third and fourth shading conditions,effectively mitigating the local power peaks.The experimental results show the proposed enhanced performance of the novel model against the other models.Graphical Abstract Remedy for physical problem correlated with solar photovoltaics Comparison with traditional and recent solar models Conclusion:NRR has effectively handled the problem related with solar models.It has improved the efficiency up to 31.44%under S4.Also,smooth output curves under S2-S4 shows its effectiveness in mitigating the local power peaks.Greater power gain at 3.94%under S4 is achieved by novel model.Real-time verification proves the supremacy of novel proposed model over other considered models in this work.

Evaluation of series-parallel-cross-tied PV array configuration performance with maximum power point tracking techniques under partial shading conditions

Tracking the maximum power point is a critical issue with solar systems.The power output of the solar panel varies due to variations in irradiance and temperature.Nonuniform irradiation due to partial shading conditions has a direct impact on the characteristics of photovoltaic(PV)systems.To build a diversity of maximum power point tracking algorithms in solar PV systems,this work focuses on perturb and observe,incremental conductance,and fuzzy logic control methodologies.The suggested fuzzy logic control method outperformed the conventional incremental conductance and perturb and observe algorithms with a collection of 49 rules.This paper presents a novel series-parallel-cross-tied PV array configuration with a developed fuzzy methodology.To comment on the performance of a proposed system under various partial shading conditions,a series-parallel PV array configuration has been considered.The simulation result demonstrates that the fuzzy method has a percentage improvement in the global maximum power point tracking efficiency of 24.85%when compared to the perturb and observe method and a 65.5%improvement when compared to the incremental conductance method under long wide partial shading conditions.In the case of the middle partial shading condition,the fuzzy method has a percentage improvement in the global maximum power point tracking efficiency of 12.4%compared to the perturb and observe method and a 60.7%improvement compared to the incremental conductance method.

Maximum Power Enhancement Under Partial Shadings Using a Modified Sudoku Reconfiguration

Partial shading is one of the important factors in reducing maximum power generation from PV(Photovoltaic)arrays.Maximum power generation can be improved by selecting a PV array through a Total-Cross-Tied(T-C-T)connection.However,maximum power generated from T-C-T can still be improved by distribution of shading over various rows.Due to distribution of shading,the current entering the node increases and results in improved maximum power generation.This can be done effectively by using Sudoku reconfiguration techniques.These techniques are economical,since they don’t require any sensors and switching networks.This technique only changes the physical location of the PV panel but the electrical connection between the panels remains the same.This paper proposes a Modified Sudoku reconfiguration pattern which enhances the maximum power from the T-C-T connected PV array.Furthermore,the theoretical calculation of row current and power output have been done for existing and proposed topologies under various shading patterns.The performance of the proposed pattern has been analyzed and compared using specifications,such as Global Maximum Power(GMP),Fill Factor(FF),mismatch losses,and efficiency.From the results,it can be concluded that the Modified Sudoku reconfiguration enhances the GMP under all shading conditions.

A Novel Triple-tied-cross-linked PV Array Configuration with Reduced Number of Cross-ties to Extract Maximum Power Under Partial Shading Conditions

Partial shadings cause output power reduction from Photovoltaic(PV)arrays due to mismatch losses.The selection of PV array configurations play a vital role in maximum power generation.This paper proposes a novel Triple-Tied-Cross-Linked(T-T-C-L)configuration to extract maximum power with a lesser number of cross ties than a Total-Cross-Tied(T-C-T)configuration.The performance of the proposed T-T-C-L configuration has been compared with various conventional PV array configurations,such as Series(S),Parallel(P),Series-Parallel(S-P),Bridge-Link(B-L),Honey-Comb(H-C),and T-C-T under Partial Shading Conditions(PSCs)by considering the 9×9 PV array.The PSCs considered are uneven row,column,diagonal,random,short&narrow,short&wide,long&narrow,long&wide shadings and uniform half module shading.The measures,such as open circuit voltage,short circuit current,maximum power,voltages and currents at maximum power,mismatch losses,fill factor and efficiency have been used for performance analysis of various configurations.From the results,it can be concluded that the performance of the proposed T-T-C-L configuration is optimal compared to other configurations.

Optimal PV Array Configuration for Extracting Maximum Power Under Partial Shading Conditions by Mitigating Mismatching Power Losses

The grid-connected or standalone PV central inverter architecture is comprised of several PV modules which are connected in different ways to form the PV array.The power generation capability of the PV array is primarily affected by partial shading conditions(PSC).Due to PSCs,the power output of the PV array is dramatically reduced,and mismatching losses are induced in the PV modules.Based on the extent of these problems,multiple peaks also appear in the power-voltage(P-V)curve,which makes it very difficult to track the global maximum power point(GMPP).The main objective of this research paper is to model and simulate the series(S),series-parallel(SP),bridge-link(BL),honey-comb(HC),total-cross-tied(TCT)and proposed triple-tied(TT)solar PV array configurations under various partial shading scenarios.The performance of all PV configurations is evaluated under a uniform approach,considering eight different shading scenarios.The performance of the considered PV configurations is analyzed in terms of their mismatching power losses,fill factors,efficiency,global maximum power points(GMPPs),local maximum power points(LMPPs),voltages and currents at GMPPs,open circuit voltage and short circuit currents.The above-mentioned PV configurations are modeled and simulated in a Matlab/Simulink environment by considering the KC-200GT module parameters.

Photovoltaic-based DC microgrid with partial shading and fault tolerance

Partial shading is a common problem that affects bus regulation in DC microgrids with several photovoltaic(PV) modules as energy sources, as a result of reduced solar irradiance reaching the modules.The problem can be mitigated by incorporating batteries, but if they are not included, appropriate control strategies must be used. This paper presents a new approach in a PV-based DC microgrid, which provides a high-quality bus voltage regulation in islanding mode, without being affected by partial shading or problems associated with PV module connection and disconnection. The solution proposed herein ensures a proper voltage regulation without being affected by problems such as failures in PV modules or mismatch between them. Besides, it can help to prevent PV partial shade stress by disconnecting the affected modules. A further advantage of the approach is the flexibility to connect more PV modules. The advantages of this approach were verified in a 200 W prototype.

Maximum power point tracking of PV system under partial shading conditions through flower pollination algorithm

For maximum utilization of solar energy,photovoltaic(PV)power systems should be operated at the maximum power point(MPP)which can be achieved using maximum power point tracking(MPPT)methods.However,the occurrence of multi-peak on P-V curve of a PV array due to the changing environmental conditions such as being partially shaded increases the complexity of the tracking process.The global MPP cannot always be achieved by the conventional MPPT methods.Therefore a novel MPPT method for PV systems using flower pollination(FP)algorithm is proposed in this paper and the Levy flight is used to improve the convergence of FP algorithm.MPPT model of the PV system is established in MATLAB to verify the effectiveness of the proposed method,and the proposed method is compared with two well established MPPT methods.The simulation results indicate that the proposed MPPT method can quickly track the changes in external environment and effectively handle the partially shaded condition.

Assessment of Cross-coupling Effects in PV String-integrated-converters with P&O MPPT Algorithm Under Various Partial Shading Patterns

A signifcant challenge in the progress and development of Building-Integrated-Photovoltaic(B-I-PV)systems is concerned with the extraction of maximum power from PV modules.The PV system archtecture is an essential feature to extract the maximum power.The conventional PV-centralinverter architecture consists of various connections among the PV modules,which are sensitive to shading effects and pro-duces mismatching power loss under partial shading conditions(PSCs),Hence,photovoltaic-distributed-maximum power point tracking(PV-D-MPPT)architecture has been proposed to extract the maximum power.In.PV-1 D-MPPT architecture,the output terminals of DC-DC converters are connected either in series or parallel configuration.The main limitation of the series configuration in open-loop MPPT control is the crosscoupling effect.Because of cross-coupling effects,the maximum-power-point(M-P-P)operation of shaded PV modules is lost under PSCs.The lost in M-P-P operation of shaded PV module also affects the unshaded modules M-P-P operation.Under crosscoupling ffeets,the DC-DC converters are consuming the power instead of delivering to the load.Despite the research activity,there are hardly any papers presenting a clear,comprehensive and mathematical analysis on the existence of cross-couplings in PV string-integrated-converters(S-1-Cs).This article presents a mathematical analysis and also explains the conditions for the existent of cross-coupling ffeets.The experimental results also validate with the mathematically analysed results.This article also discusses the modeling of the two-diode model of PV module,design of boost type S-1C,and the Perturb and Observe(P&O)MPPT algorithm implementation.

Modeling and Analysis of PV Configurations to Extract Maximum Power Under Partial Shading Conditions

Photovoltaics(PV)are widely used as renewable energy sources for standalone and grid connected PV systems.But these PV systems face major reduction in output power and efficiency due to Partial Shading Conditions(PSCs).This research paper focuses on the different choices of optimum PV Configuration under a given shading pattern to extract maximum power by mitigating mismatching loss.Various PV configurations,such as Series(S),Series Parallel(SP),Total Cross Tied(TCT),Bridge Linked(BL),Honey Comb(HC)and Alternate Total Cross Tied–Bridge Linked(A-TCT-BL)are modeled and analyzed under PSCs.Nine shading patterns,such as center,diagonal,corner,L-shaped,short and narrow,short and wide,long and narrow,long and wide and random,are considered to study the behavior of a 6×6 array form of a PV Configuration.Their performances are compared based on open circuit voltage,short circuit current,global maximum power point(GMPP),maximum voltage,maximum current,shading loss,fill factor,mismatching loss and efficiency.A novel Hybrid Configuration called A-TCT-BL PV Configuration is proposed to generate maximum power under PSCs and to minimize the number of cross ties and wiring complexities.This Configuration is an integration of TCT and BL PV Configuration and the simulation results prove the capability of this proposed PV Configuration to generate maximum power,fill factor,efficiency and minimum mismatching loss compared to S,SP,BL and HC PV Configurations under a majority of the PSCs investigated.A Canadian Solar CS5P-200M PV module is considered for simulation and is simulated using Matlab/Simulink software.

Stochastic maximum power point tracking of photovoltaic energy system under partial shading conditions

A large portion of the available power generation of a photovoltaic (PV) array could be wasted due to partial shading, temperature and irradiance effects, which create current/voltage imbalance between the PV modules. Partial shading is a phenomenon which occurs when some modules in a PV array receive non-uniform irradiation due to dust, cloudy weather or shadows of nearby objects such as buildings, trees, mountains, birds etc. Maximum power point tracking (MPPT) techniques are designed in order to deal with this problem. In this research, a Markov Decision Process (MDP) based MPPT technique is proposed. MDP consists of a set of states, a set of actions in each state, state transition probabilities, reward function, and the discount factor. The PV system in terms of the MDP framework is modelled first and once the states, actions, transition probabilities, and reward function, and the discount factor are defined, the resulting MDP is solved for the optimal policy using stochastic dynamic programming. The behavior of the resulting optimal policy is analyzed and characterized, and the results are compared to existing MPPT control methods.

Optimal PV array reconfiguration under partial shading condition through dynamic leader based collective intelligence

This paper applies the innovative idea of DLCI to PV array reconfiguration under various PSCs to capture the maxi-mum output power of a PV generation system.DLCI is a hybrid algorithm that integrates multiple meta-heuristic algo-rithms.Through the competition and cooperation of the search mechanisms of different metaheuristic algorithms,the local exploration and global development of the algorithm can be effectively improved to avoid power mismatch of the PV system caused by the algorithm falling into a local optimum.A series of discrete operations are performed on DLCI to solve the discrete optimization problem of PV array reconfiguration.Two structures(DLCI-I and DLCI-II)are designed to verify the effect of increasing the number of sub-optimizers on the optimized performance of DLCI by simulation based on 10 cases of PSCs.The simulation shows that the increase of the number of sub-optimizers only gives a relatively small improvement on the DLCI optimization performance.DLCI has a significant effect on the reduction in the number of power peaks caused by PSC.The PV array-based reconstruction system of DLCI-II is reduced by 4.05%,1.88%,1.68%,0.99%and 3.39%,when compared to the secondary optimization algorithms.