Jubaer Ahmed | Edinburgh Napier University (original) (raw)
Papers by Jubaer Ahmed
IEEE Access, 2021
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IEEE Transactions on Industrial Informatics , 2017
—This paper proposes an accurate detection scheme that effectively differentiates the partial sha... more —This paper proposes an accurate detection scheme that effectively differentiates the partial shading from the uniform change of irradiance. By doing so, it avoids the unnecessary global peak search which results in a drop of the maximum power point tracker (MPPT) efficiency. The detection is achieved by calculating the irradiance at two designated points on the I-V curve namely, i.e. the short circuit (Isc) and MPP (Impp) currents. Since the mismatch of irradiance at these two points differs greatly for the partial shading and uniform irradiance change, the occurrence of the former is easily discriminated. To prove its effectiveness, the scheme is integrated into perturb and observe (P&O) and particle swarm optimization MPPT algorithms using a buck-boost converter. Its performance under several partial shading and dynamic shading condition is simulated using Matlab/Simulink and validated using the dSpace DS1104 platform. It only requires 3 samples to determine if partial shading occurs; without the scheme, an unnecessary scans of the entire P-V curve is initiated. Consequently, MPPT transient efficiency is increased by 30-35%. In addition to this, the calculated irradiance is utilized to update the open circuit voltage of the array, thus eliminates the use of temperature and irradiance sensors.
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—This work proposes a method to reduce the steady state oscillation and to mitigate the probabili... more —This work proposes a method to reduce the steady state oscillation and to mitigate the probability of losing the tracking direction of the perturb and observed (P&O) based maximum power point tracking (MPPT) for PV system. The modified scheme retains the conventional P&O structure, but with a unique technique to dynamically alter the perturbation size. At the same time, a dynamic boundary condition is introduced to ensure that the algorithm will not diverge from its tracking locus. The modified P&O is simulated in Matlab Simulink and its performance is benchmarked using the standard MPPT efficiency (ηMPPT) calculation. Furthermore, the proposed concept is validated experimentally using a buck-boost converter, fed by a solar PV array simulator (PVAS). Based on the EN 50530 dynamic irradiance tests, the proposed method achieved an average ηMPPT almost 1.1% higher than the conventional P&O when irradiance changes slowly and about 12% higher under fast change of irradiance.
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For a photovoltaic (PV) system, it is widely assumed that the peaks of a partially shaded P–V cur... more For a photovoltaic (PV) system, it is widely assumed
that the peaks of a partially shaded P–V curve are located at the
multiples of 0.8Voc, where Voc is the open-circuit voltage of the PV module. However, this assumption—known as the of 0.8Voc model
for partial shading—is not necessarily true. If the same model is
used to design the maximum power point tracker (MPPT), it is
very likely that the algorithm will scan the wrong region of the P–V curve and, hence, an incorrect global peak detection. This paper
attempts to prove the inadequacy of the 0.8Voc model when the number of modules in the string increases. Further, the work suggests a simple relationship to predict the correct position of the
peaks. It is found that for a string of 20 modules (Voc of 400 V), the maximum deviation between the actual and computed peak is less than 3 V, while for the 0.8Voc model, the deviation reaches up to 50 V. In addition, using the proposed method, the MPPT efficiency can be improved by approximately 2%.
Bookmarks Related papers MentionsView impact
This paper proposes a method to improve the efficiency of the P&O maximum power point tracker (MP... more This paper proposes a method to improve the efficiency of the P&O maximum power point tracker (MPPT) by reducing the steady state oscillation and eliminating the possibility of the algorithm to lose its tracking direction. A dynamic perturbation step-size is employed to reduce the oscillation, while boundary conditions are introduced to prevent it from diverging away from the MPP. To prove its effectiveness, the proposed P&O is compared with the conventional and adaptive P&O using the Ropp, sinusoidal and ramp irradiance tests. In addition, the performances are evaluated based on a one-day (10 h) irradiance and temperature profile. The algorithm is implemented on a buck-boost converter and benchmarked by the standard MPPT efficiency (ηMPPT) calculation. It was found that, for all the tests, the ηMPPT of the proposed P&O scheme is increased by approximately two percentage points. Besides, the proposed algorithm does not require any extra hardware components; only several lines of additional software codes are to be embedded into the conventional P&O MPPT control program
Bookmarks Related papers MentionsView impact
As photovoltaic (PV) system suffers considerable energy loss due to partial shading (PS), various... more As photovoltaic (PV) system suffers considerable energy loss due to partial shading (PS), various approaches have been proposed to mitigate this problem. Among these, improving the maximum power point tracker (MPPT) algorithm seems to be the most feasible and economical solution. To date, there appears to be an absence of a single review paper that critically evaluates the performance of various types of MPPT algorithms during PS. To fill this gap, fifty prominent works on PS are analyzed from the theoretical and operational point of view. In particular, the paper will closely address the accurate detection for PS occurrence and the efficiency of global peak tracking. For certain selected cases, in-depth analysis is carried out to allow for an improved understanding on the operational intricacies of the algorithm. It is envisaged that this review paper would be a valuable one-stop reference to enable PV professionals to make more informed decisions when designing or choosing new MPPT algorithms for their inverters.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
This paper presents a novel approach to determine the maximum power point (MPP) in Photovoltaic (... more This paper presents a novel approach to determine the maximum power point (MPP) in Photovoltaic (PV) System using the Cuckoo Search (CS) algorithm. In CS, three samples of voltage are generated randomly over the span of the PV voltage. Based on the Le'vy distribution, the voltage samples are directed towards the best solution and on the basis of power comparison, the best position is found. The algorithm is simulated using MATLAB and compared to the conventional P&O method. It exhibits very fast convergence with zero steady state oscillation. In addition, it tracks the MPP perfectly when PV system is subjected to rapid changes of atmospheric condition.
Bookmarks Related papers MentionsView impact
IEEE Access, 2021
Bookmarks Related papers MentionsView impact
IEEE Transactions on Industrial Informatics , 2017
—This paper proposes an accurate detection scheme that effectively differentiates the partial sha... more —This paper proposes an accurate detection scheme that effectively differentiates the partial shading from the uniform change of irradiance. By doing so, it avoids the unnecessary global peak search which results in a drop of the maximum power point tracker (MPPT) efficiency. The detection is achieved by calculating the irradiance at two designated points on the I-V curve namely, i.e. the short circuit (Isc) and MPP (Impp) currents. Since the mismatch of irradiance at these two points differs greatly for the partial shading and uniform irradiance change, the occurrence of the former is easily discriminated. To prove its effectiveness, the scheme is integrated into perturb and observe (P&O) and particle swarm optimization MPPT algorithms using a buck-boost converter. Its performance under several partial shading and dynamic shading condition is simulated using Matlab/Simulink and validated using the dSpace DS1104 platform. It only requires 3 samples to determine if partial shading occurs; without the scheme, an unnecessary scans of the entire P-V curve is initiated. Consequently, MPPT transient efficiency is increased by 30-35%. In addition to this, the calculated irradiance is utilized to update the open circuit voltage of the array, thus eliminates the use of temperature and irradiance sensors.
Bookmarks Related papers MentionsView impact
—This work proposes a method to reduce the steady state oscillation and to mitigate the probabili... more —This work proposes a method to reduce the steady state oscillation and to mitigate the probability of losing the tracking direction of the perturb and observed (P&O) based maximum power point tracking (MPPT) for PV system. The modified scheme retains the conventional P&O structure, but with a unique technique to dynamically alter the perturbation size. At the same time, a dynamic boundary condition is introduced to ensure that the algorithm will not diverge from its tracking locus. The modified P&O is simulated in Matlab Simulink and its performance is benchmarked using the standard MPPT efficiency (ηMPPT) calculation. Furthermore, the proposed concept is validated experimentally using a buck-boost converter, fed by a solar PV array simulator (PVAS). Based on the EN 50530 dynamic irradiance tests, the proposed method achieved an average ηMPPT almost 1.1% higher than the conventional P&O when irradiance changes slowly and about 12% higher under fast change of irradiance.
Bookmarks Related papers MentionsView impact
For a photovoltaic (PV) system, it is widely assumed that the peaks of a partially shaded P–V cur... more For a photovoltaic (PV) system, it is widely assumed
that the peaks of a partially shaded P–V curve are located at the
multiples of 0.8Voc, where Voc is the open-circuit voltage of the PV module. However, this assumption—known as the of 0.8Voc model
for partial shading—is not necessarily true. If the same model is
used to design the maximum power point tracker (MPPT), it is
very likely that the algorithm will scan the wrong region of the P–V curve and, hence, an incorrect global peak detection. This paper
attempts to prove the inadequacy of the 0.8Voc model when the number of modules in the string increases. Further, the work suggests a simple relationship to predict the correct position of the
peaks. It is found that for a string of 20 modules (Voc of 400 V), the maximum deviation between the actual and computed peak is less than 3 V, while for the 0.8Voc model, the deviation reaches up to 50 V. In addition, using the proposed method, the MPPT efficiency can be improved by approximately 2%.
Bookmarks Related papers MentionsView impact
This paper proposes a method to improve the efficiency of the P&O maximum power point tracker (MP... more This paper proposes a method to improve the efficiency of the P&O maximum power point tracker (MPPT) by reducing the steady state oscillation and eliminating the possibility of the algorithm to lose its tracking direction. A dynamic perturbation step-size is employed to reduce the oscillation, while boundary conditions are introduced to prevent it from diverging away from the MPP. To prove its effectiveness, the proposed P&O is compared with the conventional and adaptive P&O using the Ropp, sinusoidal and ramp irradiance tests. In addition, the performances are evaluated based on a one-day (10 h) irradiance and temperature profile. The algorithm is implemented on a buck-boost converter and benchmarked by the standard MPPT efficiency (ηMPPT) calculation. It was found that, for all the tests, the ηMPPT of the proposed P&O scheme is increased by approximately two percentage points. Besides, the proposed algorithm does not require any extra hardware components; only several lines of additional software codes are to be embedded into the conventional P&O MPPT control program
Bookmarks Related papers MentionsView impact
As photovoltaic (PV) system suffers considerable energy loss due to partial shading (PS), various... more As photovoltaic (PV) system suffers considerable energy loss due to partial shading (PS), various approaches have been proposed to mitigate this problem. Among these, improving the maximum power point tracker (MPPT) algorithm seems to be the most feasible and economical solution. To date, there appears to be an absence of a single review paper that critically evaluates the performance of various types of MPPT algorithms during PS. To fill this gap, fifty prominent works on PS are analyzed from the theoretical and operational point of view. In particular, the paper will closely address the accurate detection for PS occurrence and the efficiency of global peak tracking. For certain selected cases, in-depth analysis is carried out to allow for an improved understanding on the operational intricacies of the algorithm. It is envisaged that this review paper would be a valuable one-stop reference to enable PV professionals to make more informed decisions when designing or choosing new MPPT algorithms for their inverters.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
This paper presents a novel approach to determine the maximum power point (MPP) in Photovoltaic (... more This paper presents a novel approach to determine the maximum power point (MPP) in Photovoltaic (PV) System using the Cuckoo Search (CS) algorithm. In CS, three samples of voltage are generated randomly over the span of the PV voltage. Based on the Le'vy distribution, the voltage samples are directed towards the best solution and on the basis of power comparison, the best position is found. The algorithm is simulated using MATLAB and compared to the conventional P&O method. It exhibits very fast convergence with zero steady state oscillation. In addition, it tracks the MPP perfectly when PV system is subjected to rapid changes of atmospheric condition.
Bookmarks Related papers MentionsView impact