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Designing the dq-frame current regulator for single-phase voltage-source inverters is a very challenging task. Since only one real current signal exists in the circuit, an orthogonal signal generation (OSG) block is required to generate the virtual orthogonal signal. Thus, ac variables can be turned into equivalent dc quantities through an αβ/dq transformation. However, the OSG block makes the control system complex and introduces an extra transient disturbance. Consequently, the dynamic performance is deteriorated. In this study, the reference-current-based OSG method is analysed thoroughly. Based on this structure, the dq-axes decoupling control, which is widely discussed for three-phase systems and usually neglected for singlephase systems, is studied. Two decoupling techniques, i.e. the reference-current feed-forward control and the quasi-complex vector proportional-integrator control, are implemented and analysed. The proposed theories and control schemes are evaluated by experimental results.

In this paper, a simple and practical design method of electric engineering maintenance rolling stock (EEMRS) is briefly presented, which is composed of six power units. It is important to improve the energy conservation and efficiency of power converters and reduce the size of the heat dissipation system for EEMRS. Therefore, loss analysis of power semiconductors is very necessary. A new modulating function is proposed on the basis of vector modulation, and the instantaneous power losses and the average conduction power losses in insulated gate bipolar transistor (IGBT) and free‐wheeling diode (FWD) are deduced from the modulating function. Additionally, considering that the junction temperature oscillates with the output frequency, a simple calculation method of the junction temperature ripple is presented, which is helpful in examining the junction temperature limited to the maximum value. Based on the analysis, a heat dissipation system for the direct/alternating current (DC/AC) inverter using forced‐air cooling is designed, and the calculation results and the experimental results are given, which verify the feasibility of the proposed method. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Introduction Evaluation of cirrhosis appears to be easily overlooked in the clinic for the HBsAg-negative (hepatitis B surface antigen-negative) and HBcAb-positive (hepatitis B core antibody-positive) population. Herein, we determine the prevalence of cirrhosis/advanced fibrosis among HBsAg-negative/HBcAb-positive US adults. Methods Data came from the National Health and Nutrition Examination Survey (NHANES) 2001–2018. A total of 3115 HBsAg-negative/HBcAb-positive US adults were enrolled in this study. We assessed cirrhosis by using the Fibrosis-4 (FIB-4) and aspartate aminotransferase to platelet ratio index (APRI) score. Results Out of 50,201 NHANES adults, 45,087 were tested for HBcAb/HBsAg, of whom 3115 met the inclusion criteria (HBsAg-negative/HBcAb-positive with available data for FIB-4/APRI). The weighted proportion of HBsAg-negative/HBcAb-positive among US adults was 4.46% (95% CI 4.17–4.75%), affecting 9.87 million US adults. According to the results of the FIB-4, the weighted prevalence of cirrhosis/advanced fibrosis among HBsAg-negative/HBcAb-positive US adults was 3.76% (95% CI 2.80–4.72%), which corresponds to 371,112 (95% CI 276,360–465,864) HBsAg-negative/HBcAb-positive American adults who had already developed cirrhosis. Among those, cirrhosis/advanced fibrosis in the HBsAb-negative (hepatitis B surface antibody) group (6.28%, 95% CI 4.10–8.45%) was significantly higher than in the HBsAb-positive group (3.08%, 95% CI 2.07–4.08%). Results were similar when APRI was used. Conclusion According to the FIB-4, 3.76% of HBsAg-negative and HBcAb-positive US adults had cirrhosis/advanced fibrosis, much higher than in the general population of the USA. Our data highlight the importance of cirrhosis screening in the HBsAg-negative/HBcAb-positive population to prevent advanced liver disease, especially in those who are HBsAb-negative. Supplementary Information The online version contains supplementary material available at 10.1007/s40121-022-00680-2.

Abstract:The overall configuration of a magnetic suspension decoupling control system is designed to realize the reliable digital control of a 3-phase bearingless induction motor whose rotor windings are not pole-specific. Based on a digital signal processor complementary metal-oxide semiconductor chip, the digital control hardware and software systems are analyzed and designed. In this paper, the calculation and regulation of the motor rotational speed, correction and regulation methods of the radial displacements, calculation and compensation algorithms of the unilateral magnetic pulls, induction compensation algorithm of the effective suspension control current, current regulation, and space-vector pulse width modulation algorithms, are presented in detail. The experimental results verify the feasibility and practicability of the designed decoupling digital control system of the 3-phase bearingless induction motor.