To achieve a high performance in sub-module power conditioning circuits, it is important that power converters are designed in accordance with the photovoltaic (PV) cell impedance at the input. Taking this one step further, exploiting the impedance of cell strings could even support novel power conditioning approaches in PV modules. In this work, we characterize the impedance of eight single-cell laminates based on different industrial c-Si PV cell architectures. This characterization is carried out by impedance spectroscopy in dark conditions at room temperature, and the capacitive and inductive effects are evaluated through equivalent model fitting. By comparing the results for the different laminates, it is revealed how the cell design affects its impedance. Our experiments show that the PN junction capacitance at maximum power point varies for the different cells between 0.30 and 45.6 μF/cm². The two main factors contributing to a high PV cell capacitance at maximum power point are (i) a low wafer dopant concentration and (ii) a high maximum power point voltage. In high-efficiency c-Si PV cells that will be fabricated in the coming years, increasing capacitances are expected for operation near the maximum power point. Furthermore, the single-cell laminates exhibit inductances between 63 and 130 nH, and our results indicate that the inductance is mostly affected by the number of busbars and the geometry of the metal contacts.

Reconfigurable photovoltaic modules are a promising approach to improve the energy yield of partially shaded systems. So far, the feasibility of this concept has been evaluated through simulations or simplified experiments. In this work, we analyse the outdoor performance of a full-scale prototype of a series-parallel photovoltaic module with six reconfigurable blocks. Over a 4-month-long period, its performance was compared to a reference photovoltaic module with static interconnections and six bypass diodes. The results show that under partial shading, the reconfigurable module produced 10.2% more energy than the reference module. In contrast, under uniform illumination the energy yield of the reconfigurable PV module was 1.9% lower due to the additional losses introduced by its switching matrix. Finally, a modification in the reconfiguration algorithm is proposed to reduce the output current–voltage range of the module and simplify the design of module-level power converters while limiting the shading tolerance loss.

The integration of photovoltaic (PV) technology in urban environments poses new challenges for the design of PV modules. In particular, the poor shading tolerance of conventional PV modules strongly limits the energy performance of urban PV systems. In this work, we analyze how interdigitated back-contact solar cells with low-breakdown voltages can help improve the shading tolerance of PV modules. Through detailed simulations, we show that the breakdown voltage can be tuned without significantly degrading the efficiency of the solar cell. Simulation results indicate that, under partial shading conditions, cells with a 0.3-V breakdown voltage could boost by 20% the annual yield of conventional crystalline silicon PV modules with three bypass diodes. These findings are supported by a four-month-long monitoring campaign of PV modules with different breakdown characteristics, which shows a specific yield gain of about 4% in PV modules with six bypass diodes.