98%
921
2 minutes
20
Under certain circumstances, a high-speed railway may require constant acceleration or emergency braking, in which case the inverter may experience short-term overload conditions and the current passing through the IGBT will go beyond the rated design tolerance. Under overload conditions, the IGBT loss will increase instantly, raising the power semiconductor device's junction temperature in the process. This research examines the boosting-gate-voltage-driven IGBT control technology. It increases the gate drive voltage and the IGBT current capacity and decreases the conduction voltage drop of IGBT under short-term overload conditions, reducing the instantaneous loss and temperature rise undulation of IGBT. The working characteristics of IGBT devices are studied, and the influence of gate drive voltage on device loss and temperature rise fluctuations is analyzed. Based on the emergency acceleration and brake conditions of the actual train operation, the short-term overload characteristics of the inverter are analyzed. The optimization analysis of the boosting gate voltage under emergency conditions is carried out, and the IGBT drive circuit with gate voltage pumping function is designed. The effectiveness of the driving circuit is verified through PSpice simulation and actual switching characteristic test. According to the analysis of experimental data, it can be verified that increasing the gate voltage technology can reduce IGBT losses.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11205778 | PMC |
http://dx.doi.org/10.3390/mi15060738 | DOI Listing |
Zhonghua Nei Ke Za Zhi
September 2025
Department of Hematology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
This report describes the case of a 43-year-old male presenting with severe anemia (hemoglobin, HGB 35 g/L). A comprehensive evaluation encompassing bone marrow morphology (24% ring sideroblasts), genetic testing (SF3B1-negative), iron metabolism studies (ferritin 1 179 μg/L), and imaging (liver MRI T2* value 1.1 ms) was performed for diagnosis, treatment planning, and assessment of outcomes.
View Article and Find Full Text PDFSao Paulo Med J
September 2025
Professor; Physician. Hospital Alemão Oswaldo Cruz, São Paulo (SP), Brazil.
Background: The coronavirus disease 2019 (COVID-19) pandemic has placed unprecedented strain on healthcare systems, particularly on critically ill patients requiring prolonged mechanical ventilation (MV). Percutaneous tracheostomy (PT) has emerged as a potential strategy to facilitate weaning, reduce intensive care unit (ICU) stay, and optimize resource use. However, the timing, safety, and outcomes of PT in COVID-19 patients remain debatable.
View Article and Find Full Text PDFHeart Fail Rev
September 2025
Emergency Institute for Cardiovascular Diseases 'Prof. C.C. Iliescu', 258 Fundeni Street, 2 District, 022328, Bucharest, Romania.
Hypertensive acute heart failure (HT-AHF) has historically been recognized as a distinct clinical phenotype of AHF, characterized by acute pulmonary congestion in the context of elevated systolic blood pressure (SBP), typically > 140 mmHg. However, emerging evidence has begun to challenge the diagnostic accuracy, clinical utility, and relevance of this category. A main criticism of HT-AHF is its considerable overlap with other AHF clinical profiles, including acute decompensated heart failure (ADHF) and acute pulmonary oedema (APO).
View Article and Find Full Text PDFSensors (Basel)
August 2025
Swinburne Research, Swinburne University of Technology, Hawthorn, Melbourne, VIC 3122, Australia.
The shift from manual to conditionally automated driving, supported by Advanced Driving Assistance Systems (ADASs), introduces challenges, particularly increased crash risks due to human factors like cognitive overload. Driving simulators provide a safe and controlled setting to study these human factors under complex conditions. This study leverages Functional Near-Infrared Spectroscopy (fNIRS) to dynamically assess cognitive load in a realistic driving simulator during a challenging night-time-rain scenario.
View Article and Find Full Text PDFMethodsX
December 2024
D.Y. Patil International University, Akurdi, Pune, India.
The important steps toward a low-carbon economy and sustainable energy future is switch to Electric Vehicles(EVs).The rapid development of EVs has brought a risk to reliability of the electrical system. However, the high electricity consumption of EVs will lead to the overload of power grid transformers.
View Article and Find Full Text PDF