The article investigates the detrimental effect of nonuniform and uniform crack distributions over a solar cell in terms of open-circuit voltage ( ${{\bm{V}}_{{{\bf oc}}}}$ ), short-circuit current density ( ${{\bm{J}}_{{{\bf sc}}}}$ ), and output power, the latter under a wide range of irradiance conditions. The experimental procedure to detect the cracks relies on electroluminescence (EL) imaging, which is nondestructive and requires a relatively low amount of time. The Griddler software is adopted to translate the EL-taken image into ${{\bm{V}}_{{{\bf oc}}}}$ and ${{\bm{J}}_{{{\bf sc}}}}$ maps. The main findings can be summarized as follows: the nonuniformly and uniformly cracked cells are both jeopardized in terms of output power; the loss corresponding to the cell with nonuniform distribution of cracks is increasingly higher than the uniformly cracked counterpart as the irradiance hitting the cells grows; and all cells affected by nonuniform cracks are severely damaged in terms of fingers and rear busbar, which concur to limit the maximum output current.

The reduction of the trap density at the SiC/SiO2 interface of a SiC MOSFET is still an open issue for the next generations development. Since TCAD simulations are one of the most powerful tools adopted in the field of power semiconductor devices, in this work we define the guidelines for the calibration of the TCAD model from the point of view of the interface traps modeling. We have carried out a qualitative analysis of the effect of the SiC/SiO2 interface traps properties on the C-V curve by means of TCAD simulations, to support the interpretation of the experimental C-V curves of a SiC MOSFET. A new approach for the simulation of the C-V curves of a SiC MOSFET is proposed as well. The aim of the paper is the analysis of the effect of the SiC/SiO2 interface traps on the C-V curve by means of TCAD simulations.

In the photovoltaic (PV) market, effective strategies regarding operation and maintenance are needed to guarantee the return of investment. Accelerated aging of PV modules and catastrophic failures, leading to undesired plant stops, must be prevented. Significant effort must be paid to avoid the occurrence of localized overheating (hot spot), which may induce, in severe cases, irreversible malfunctioning and even fire. In this paper, an innovative concept of PV module, not affected by hot spots, is presented. The module is equipped with a bypass and disconnection circuit, replacing traditional diodes in the junction box. The behavior of the circuit is described to explain its peculiar bypass mechanism along with the impact on the operation of the PV module under different conditions. Moreover, experimental tests have been conducted to fairly compare, under the worst condition, consisting of a bypass event due to a single malfunctioning cell, the proposed solution with a traditional PV module adopting bypass diodes. IR analysis has been performed to map the temperature distribution on the module. Results show that, in the proposed PV module, the malfunctioning cell operates close to the temperature of the other cells, while in a traditional module significant overtemperature occurs.

The aim of this work is to investigate the degradation of perovskite solar cells (PSCs) by means of impedance spectroscopy, a highly sensitive characterization technique used to establish the electrical response of a device in a nondestructive manner. In this paper, PSCs with two different electron transport layers (ETLs) are studied: PSCs with undoped SnO₂ as an ETL are compared to PSCs with an ETL composed of graphene-doped SnO₂ (G-SnO₂). Experimental data were collected immediately after fabrication and after one week, monitoring both impedance spectroscopy and dark current-voltage (I-V) curves. It was observed that, in the case of the undoped PSCs, the degradation of the solar cells affected both the AC behavior of the devices, modifying the associated Nyquist plots, and the DC behavior, observable from the dark I-V measurements. Conversely, the solar cells with G-SnO₂ showed no variation. Considering the Nyquist plots, a quantitative analysis was performed by comparing the parameters of a proper equivalent circuit model. The results were coherent with those achieved in the DC analysis, thus proving that the analysis of impedance spectra, supported with dark I-V curves, allows one to gain a deeper knowledge of the degradation phenomena of perovskite solar cells. This study opens the door for further improvement of these devices through a better understanding of their electrical behavior.

Residual lifetime estimation has gained a key point among the techniques that improve the reliability and the efficiency of power converters. The main cause of failures are the junction temperature cycles exhibited by switching devices during their normal operation; therefore, reliable power converter lifetime estimation requires the knowledge of the junction temperature time profile. Since on-line dynamic temperature measurements are extremely difficult, in this work an innovative real-time monitoring strategy is proposed, which is capable of estimating the junction temperature profile from the measurement of the dissipated powers through an accurate and compact thermal model of the whole power module. The equations of this model can be easily implemented inside a FPGA, exploiting the control architecture already present in modern power converters. Experimental results on an IGBT power module demonstrate the reliability of the proposed method.