Operating photovoltaic (PV) systems under partial shading conditions results in significant power losses. To mitigate partial shading effects, distributed maximum power point tracking (DMPPT) architectures have been proposed. An emerging DMPPT technique represented by PV module cascaded converters (MCCs) has been widely reported in the literature. In this architecture, a DC converter is allocated for each PV module to process and maximise its power. In this sense, mismatch effects are mitigated between PV modules. While MCC architecture has prominent advantages and value-added features, its challenges and limitations cannot be ignored. This study presents a comprehensive review of the state of the art of PV MCC architecture to help readers realise the progress of this DMPPT technique. Several points are extensively discussed and analysed including concept realisation and analysis, DC converter topologies and design optimisation, DMPPT performance limitations, DMPPT control, and protection. The main concepts are reemphasised through a set of simulations. Finally, a list of potential research areas in this field is introduced.

Wind power uncertainties have made the large integration of wind power generating units in the power system highly challenging. One promising solution to overcome the challenges associated with the intermittency of the renewable energy resources (RESs) is to connect areas with diverse renewable energy portfolios via high voltage direct current (HVDC) transmission lines with controllable power transfer capability. The installation of HVDC transmission lines in the power system has resulted in the evolution of conventional alternating current (AC) networks to mixed AC-HVDC power systems. In this study, to address wind power uncertainties in mixed AC-HVDC multi-area power systems, a modified robust optimisation (RO) model for the security-constrained economic dispatch (SCED) problem is proposed. The proposed RO model is used to minimise the generation cost and wind power curtailment under the worst-case scenario of actual wind power. Unlike the existing RO models, the proposed RO model considers a modified uncertainty set based on the wind power admissibility and addresses the budget of uncertainty more accurately to adjust the solution's level of conservatism. Extensive numerical studies demonstrate the economic and operational advantages of the proposed RO model for solving the SCED problem in mixed AC-HVDC power systems with high penetration of RESs.

In this study, the distribution effect of grid-connected inverters in photovoltaic (PV) plants is analysed. In fact, the interaction dynamics between different arrangements of distributed PV inverters and the grid are thoroughly compared. To this aim, the total power of all arrangements of distributed inverters is considered constant, which is called fixed-power arrangements in this work. Accordingly, this study first develops the model of grid-connected current-controlled inverters (CCIs). Then, by applying the impedance-based criterion, the effect of CCIs distribution on their stability is evaluated. Despite the fact that each CCI model is obtained based on the same stability margins, different distributed arrangements of CCIs have different interaction dynamics with the grid. From the frequency-domain analysis, it is found that the distribution effect of CCIs can greatly affect the high-frequency (HF) behaviour of their output admittances, and consequently improves their interaction dynamics; hence, one of the factors which can also play an important role in HF behaviour is distribution effect of CCIs in a PV plant. The simulation studies of several distributed arrangements of CCIs as well as a centralised CCI confirm the validity of the performed analysis.

This study is interested in optimisation of both sizing and energy management system of a hybrid storage system (HSS) associated with photovoltaic panels. The battery (BT) considered as the principal storage organ and a super-capacitor used as the secondary storage system to improve the BT life span makes up the HSS. The main purpose of this study is to explore a novel optimisation approach to jointly optimise the sizing and the fuzzy logic energy management system (FLEMS). In fact, an optimisation function based on sequential quadratic programming algorithm is proposed. The optimisation methodology has been performed jointly and successfully for the sizing of the BT storage system and the membership functions parameters of the FLEMS in order to decrease the levelised cost of energy with a violation time by 5% of mean absolute percentage error score <1.5% throughout the year. According to the simulations results, a benefit analysis has been done to assess the associated financial impact.

The phenomenon of partial shading adversely affects photovoltaic arrays, e.g. multiple peak points in – characteristic curves and reducing the output power. Array reconfiguration is the best and efficient way of alleviating the partial shading effects. Physical relocation of panels can be used as a practical solution to prevent shading problems by altering the physical location of panels by not changing its electrical circuit. In this study, a new reconfiguration technique named as Arrow Sudoku pattern is proposed for all the conventional configurations such as, series–parallel, bridge-link, honeycomb, and total cross-tied connections to mitigate the shading effects. The proposed approach is tested on a Solar Photo-Voltaic (SPV) array for different groups of shading conditions. The results are simulated through MATLAB/Simulink and validated through hardware prototype using artificial shade blockers and the results show a good improvement in the diagnosis of output parameters for all the reconfiguration techniques in comparison with their initial configurations. Moreover, the disturbance caused in – characteristic curves by shading is eradicated by using this proposed technique.