21:T4ac,A new record conversion efficiency of 24.7% was attained at the research level by using a heterojunction with intrinsic thin-layer structure of practical size (101.8 cm ² , total area) at a 98-μm thickness. This is a world height record for any crystalline silicon-based solar cell of practical size (100 cm ² and above). Since we announced our former record of 23.7%, we have continued to reduce recombination losses at the hetero interface between a-Si and c-Si along with cutting down resistive losses by improving the silver paste with lower resistivity and optimization of the thicknesses in a-Si layers. Using a new technology that enables the formation of a-Si layer of even higher quality on the c-Si substrate, while limiting damage to the surface of the substrate, the V _oc has been improved from 0.745 to 0.750 V. We also succeeded in improving the fill factor from 0.809 to 0.832.22:T41b,Recently, several parameters relevant for modeling crystalline silicon solar cells were improved or revised, e.g., the international standard solar spectrum or properties of silicon such as the intrinsic recombination rate and the intrinsic carrier concentration. In this study, we analyzed the influence of these improved state-of-the-art parameters on the limiting efficiency for crystalline silicon solar cells under 1-sun illumination at 25°C, by following the narrow-base approximation to model ideal solar cells. We also considered bandgap narrowing, which was not addressed so far with respect to efficiency limitation. The new calculations that are presented in this study result in a maximum theoretical efficiency of 29.43% for a 110-μm-thick solar cell made of undoped silicon. A systematic calculation of the I-V parameters as a function of the doping concentration and the cell thickness together with an analysis of the loss current at maximum power point provides further insight into the intrinsic limitations of silicon solar cells.23:T443,The current losses due to parasitic absorption in the indium tin oxide (ITO) and amorphous silicon (a-Si:H) layers at the front of silicon heterojunction solar cells are isolated and quantified. Quantum efficiency spectra of cells in which select layers are omitted reveal that the collection efficiency of carriers generated in the ITO and doped a-Si:H layers is zero, and only 30% of light absorbed in the intrinsic a-Si:H layer contributes to the short-circuit current. Using the optical constants of each layer acquired from ellipsometry as inputs in a model, the quantum efficiency and short-wavelength current loss of a heterojunction cell with arbitrary a-Si:H layer thicknesses and arbitrary ITO doping can be correctly predicted. A 4 cm ² solar cell in which these parameters have been optimized exhibits a short-circuit current density of 38.1 mA/cm ² and an efficiency of 20.8%.24:T53e,The main objective of this study is to increase the penetration level of photovoltaic (PV) power production in low-voltage (LV) grids by means of solar inverters with reactive power control capability. This paper underlines weak points of standard reactive power strategies which are already imposed by certain grid codes, and then, the study introduces a new reactive power control method that is based on sensitivity analysis. The sensitivity analysis shows that the same amount of reactive power becomes more effective for grid voltage support if the solar inverter is located at the end of a feeder. Based on this fundamental knowledge, a location-dependent power factor set value can be assigned to each inverter, and the

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