@article{MTMT:31933543, title = {Combined electro-thermal model for PV panels}, url = {https://m2.mtmt.hu/api/publication/31933543}, author = {Abdulrazzaq, Ali Kareem and Bognár, György and Plesz, Balázs}, doi = {10.1556/606.2020.00145}, journal-iso = {POLLACK PERIODICA}, journal = {POLLACK PERIODICA: AN INTERNATIONAL JOURNAL FOR ENGINEERING AND INFORMATION SCIENCES}, volume = {16}, unique-id = {31933543}, issn = {1788-1994}, abstract = {This paper presents a combined electro-thermal model to serve the aim of accurate output power prediction of photovoltaic systems, based on the concept of the thermal energy balance. The electrical sub-model is built based on fitting a surface to the current-voltage curves collected under wide range temperatures and irradiances. For this purpose, the current-voltage characteristic curves are reproduced using two different methods. The thermal sub-model considers all the effective heat transfer mechanisms to estimate the photovoltaic module junction temperature. The Newton-Raphson iterative method is used as a solving algorithm to calculate the photovoltaic junction temperature. The collected results prove the applicability of the model under a wide range of environmental conditions.}, year = {2021}, eissn = {1788-3911}, pages = {7-13}, orcid-numbers = {Abdulrazzaq, Ali Kareem/0000-0002-3633-2766; Bognár, György/0000-0003-4582-3900} } @article{MTMT:31395925, title = {Mixed Detailed and Compact Multi-Domain Modeling to Describe CoB LEDs}, url = {https://m2.mtmt.hu/api/publication/31395925}, author = {Pohl, László and Hantos, Gusztáv and Hegedüs, János and Németh, Márton and Kohári, Zsolt and Poppe, András}, doi = {10.3390/en13164051}, journal-iso = {ENERGIES}, journal = {ENERGIES}, volume = {13}, unique-id = {31395925}, issn = {1996-1073}, abstract = {Large area multi-chip LED devices, such as chip-on-board (CoB) LEDs, require the combined use of chip-level multi-domain compact LED models (Spice-like compact models) and the proper description of distributed nature of the thermal environment (the CoB substrate and phosphor) of the LED chips. In this paper, we describe such a new numerical solver that was specifically developed for this purpose. For chip-level, the multi-domain compact modeling approach of the Delphi4LED project is used. This chip-level model is coupled to a finite difference scheme based numerical solver that is used to simulate the thermal phenomena in the substrate and in the phosphor (heat transfer and heat generation). Besides solving the 3D heat-conduction problem, this new numerical simulator also tracks the propagation and absorption of the blue light emitted by the LED chips, as well as the propagation and absorption of the longer wavelength light that is converted by the phosphor from blue. Heat generation in the phosphor, due to conversion loss (Stokes shift), is also modeled. To validate our proposed multi-domain model of the phosphor, dedicated phosphor and LED package samples with known resin—phosphor powder ratios and known geometry were created. These samples were partly used to identify the nature of the temperature dependence of phosphor-conversion efficiency and were also used as simple test cases to “calibrate” and test the new numerical solver. With the models developed, combined simulation of the LED chip and the CoB substrate + phosphor for a known CoB LED device is shown, and the simulation results are compared to measurement results.}, year = {2020}, eissn = {1996-1073}, orcid-numbers = {Pohl, László/0000-0003-2390-1381; Hantos, Gusztáv/0000-0002-0401-2098; Hegedüs, János/0000-0003-4792-6225; Németh, Márton/0000-0002-3517-5359; Kohári, Zsolt/0000-0002-9908-6291; Poppe, András/0000-0002-9381-6716} } @article{MTMT:3204967, title = {Thermoelectrical modelling and simulation of devices based on VO2}, url = {https://m2.mtmt.hu/api/publication/3204967}, author = {Pohl, László and Soma, Ur and Mizsei, János}, doi = {10.1016/j.microrel.2017.03.027}, journal-iso = {MICROELECTRON RELIAB}, journal = {MICROELECTRONICS RELIABILITY}, volume = {79}, unique-id = {3204967}, issn = {0026-2714}, abstract = {Limits of development of conventional silicon-based integrated circuits get closer. More and more effort is done to develop new devices for integrated circuits. A promising structure is based on the semiconductor-to-metal phase change of vanadium-dioxide at about 67 °C. In these circuits the information is carried by combined thermal and electrical currents. For device modelling and circuit design, accurate distributed electro-thermal transient simulation is mandatory. This paper is the first one to present an electro-thermal transient simulation method for VO2 devices operating in real-world conditions. The paper presents three VO2 material models, the algorithmic extension of an electro-thermal field simulator to be able to handle hysteresis and the transient simulation issues of VO2 and the modelling of VO2 based devices. The paper compares measured and simulated device characteristics.}, year = {2017}, eissn = {1872-941X}, pages = {387-394}, orcid-numbers = {Pohl, László/0000-0003-2390-1381; Mizsei, János/0000-0003-3411-1502} }