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A reconfiguration technique using a switched-capacitor (SC)-based voltage equalizer differential power processing (DPP) concept is proposed in this paper for photovoltaic (PV) systems at a cell/subpanel/panel-level. The proposed active diffusion charge redistribution (ADCR) architecture increases the energy yield during mismatch and adds a voltage boosting capability to the PV system under no mismatch by connected the available PV cells/panels in series. The technique performs a reconfiguration by measuring the PV cell/panel voltages and their irradiances. The power balancing is achieved by charge redistribution through SC under mismatch conditions, e.g., partial shading. Moreover, PV cells/panels remain in series under no mismatch. Overall, this paper analyzes, simulates, and evaluates the effectiveness of the proposed DPP architecture through a simulation-based model prepared in PSIM. Additionally, the effectiveness is also demonstrated by comparing it with existing conventional DPP and traditional bypass diode architecture.

Partial shading affects the energy harvested from photovoltaic (PV) modules, leading to a mismatch in PV systems and causing energy losses. For this purpose, differential power processing (DPP) converters are the emerging power electronic-based topologies used to address the mismatch issues. Normally, PV modules are connected in series and DPP converters are used to extract the power from these PV modules by only processing the fraction of power called mismatched power. In this work, a switched-capacitor-inductor (SCL)-based DPP converter is presented, which mitigates the non-ideal conditions in solar PV systems. A proposed SCL-based DPP technique utilizes a simple control strategy to extract the maximum power from the partially shaded PV modules by only processing a fraction of the power. Furthermore, an operational principle and loss analysis for the proposed converter is presented. The proposed topology is examined and compared with the traditional bypass diode technique through simulations and experimental tests. The efficiency of the proposed DPP is validated by the experiment and simulation. The results demonstrate the performance in terms of higher energy yield without bypassing the low-producing PV module by using a simple control. The results indicate that achieved efficiency is higher than 98% under severe mismatch (higher than 50%).

Partial shading reduces energy production and affects the lifetime of the overall PV system. To mitigate the mismatch effects caused by partial shading, several PV cell- or sub-panel-level techniques employing power electronics have been proposed in the literature, where discrete passive components, e.g., inductors and capacitors, are also used. In this paper, a differential power processing (DPP) technique, which utilizes only the intrinsic capacitance of solar cells, is introduced for small-scale PV applications. The developed DPP topology mitigates the mismatch effects by operating all PV cells at or near to their corresponding maximum power points (MPPs) even under mismatch conditions. The analysis of the topology and its comparison with the frequently used series- and series-parallel (SP)-connected techniques, are presented to validate its efficacy and operational capabilities, through simulation results. Moreover, a prototype is built to verify the topology. The experimental results confirm the elimination of multiple power peaks under mismatch along with maintaining the same voltages across the PV panels.

Energy harvesting from solar photovoltaic (PV) modules is affected by partial shading (contributes to mismatch issues), which in turn affects the entire system efficiency. Various power electronics converters have thus been investigated to address the mismatch issue due to partial shading, where the charges between PV submodules (typically, three submodules in a PV module) are redistributed. As a representative of the power electronic-based techniques, differential power processing (DPP) converters can improve the power extraction from the series-connected PV submodules. In this paper, a switched-capacitor-inductor (SCL)-based DPP converter is proposed to mitigate the mismatch effect for PV modules. The proposed converter only processes the differential power, enabling extraction of the maximum power from the PV module at a submodule level. The proposed topology is analyzed and compared with the traditional (Schottky) bypassing technique through simulations. Partial shading experiments are also performed for the traditional technique. A benchmarking with the prior-art DPP converters and experimental tests on the switched-inductor (SL)-based DPP topology are presented in this paper.

The partial shading on parallel-connected photovoltaic (PV) modules introduces severe mismatch issues in PV systems, which significantly affects the overall output power. Distributed maximum power point tracking (DMPPT) is considered as an effective solution to the resultant mismatch in parallel-connected PV sub-modules. In this context, this paper proposes a sub-module level switched-inductor (SL) based differential power processing (DPP) technique for parallel connections to alleviate the mismatch effect. The technique can achieve the maximum output power under mismatch by equalizing the sub-module voltages. The proposed technique is analyzed and compared through simulations with a traditional (Schottky diode) bypassing technique.

The installation of photovoltaic (PV) systems is continuously increasing in both standalone and grid-connected applications. The energy conversion from solar PV modules is not very efficient, but it is clean and green, which makes it valuable. The energy output from the PV modules is highly affected by the operating conditions. Varying operating conditions may lead to faults in PV modules, e.g. the mismatch faults, which may occur due to shadows over the modules. Consequently, the entire PV system performance in terms of energy production and lifetime is degraded. To address this issue, mismatch mitigation techniques have been developed in the literature. In this context, this study provides a review of the state-of-the-art mismatch mitigation techniques, and operational principles of both passive and active techniques are briefed for better understanding. A comparison is presented among all the techniques in terms of component count, complexity, efficiency, cost, control, functional reliability, and appearance of local maximums. Selected techniques are also benchmarked through simulations. This review serves as a guide to select suitable techniques according to the corresponding requirements and applications. More importantly, it is expected to spark new ideas to develop advanced mismatch mitigation techniques.

Partial shading on photovoltaic (PV) arrays reduces the overall output power and causes multiple maximas on the output power characteristics. Due to the introduction of multiple maximas, mismatch power losses become apparent among multiple PV modules. These mismatch power losses are not only a function of shading characteristics, but also depend on the placement and interconnection patterns of the shaded modules within the array. This research work is aimed to assess the performance of 4 × 4 PV array under different shading conditions. The desired objective is to attain the maximum output power from PV modules at different possible shading patterns by using power electronic-based differential power processing (DPP) techniques. Various PV array interconnection configurations, including the series-parallel (SP), total-cross-tied (TCT), bridge-linked (BL), and center-cross-tied (CCT) are considered under the designed shading patterns. A comparative performance analysis is carried out by analyzing the output power from the DPP-based architecture and the traditional Schottky diode-based architecture. Simulation results show the gain in the output power by using the DPP-based architecture in comparison to the traditional bypassing diode method.

Partial shading affects the performance and reliability of thin-film and crystalline-silicon (c-Si) photovoltaic (PV) modules. In this paper, the thin-film and c-Si modules are experimentally benchmarked by introducing various partial shading patterns over the modules. More specifically, experiments are performed using SPISUN 5600 SLP-based test-rig. The benchmarking reveals that thin-film and c-Si technologies behave differently under the same shading patterns. Furthermore, thermographic images are also presented to explore the effect of partial shading on both modules.