Search

An approach is presented to employ two different types of converters in bridgeless configuration for supply side power factor enhancement of the system. The isolated single‐stage electric vehicle battery charger uses two different converters in a bridgeless configuration to extract the advantages of both converters for supply‐side power factor enhancement. For the negative and positive semi‐cycles of the supply voltage, the power factor‐enhanced asymmetrical alternating current–direct current converter utilises a fourth order single‐ended primary‐inductor converter and a second order buck‐boost converter, respectively. The use of single‐ended primary‐inductor converter and buck‐boost converter in bridgeless configuration reduces the net order of the system with respect to conventional bridgeless‐single‐ended primary‐inductor converter schemes. The buck‐boost converter also needs the supply‐side filter to eradicate the unwanted harmonics in the supply current which increases the order of the system. The usage of both converters presents many benefits like input inductance of the single‐ended primary‐inductor converter can be utilised as a filtering element with a capacitor for the buck‐boost converter. The anti‐parallel diode conduction operation of both switches facilitates the elimination of extra reverse feed diodes (generally used in bridgeless schemes). The single‐stage charger itself comes with the benefit of elimination of extra stages and thus the losses associated with it. The presented charger also witnesses the elimination of the rectifier due to usage of bridgeless configuration. The isolated single‐stage electric vehicle battery charger is also garnished with electrical isolation which adds to the safety standard of the system. To attain power factor enhancement, the asymmetrical alternating current–direct current converter functions in discontinuous current conduction mode in the present work. The elimination of extra‐stages (with respect to two stage charger), a filter, a rectifier, two extra reverse‐feeding diodes, one voltage sensor, one current sensor (with respect to continuous current conduction mode), and electrical isolation not only makes the system compact and safer but also makes the system cheaper. Elaborated mathematical modelling and stability analysis of the presented alternating current–direct current converter using a pole‐zero map and bode plot have been included in the article. The prototype and MATLAB/Simulink model of isolated single‐stage electric vehicle battery charger system with discontinuous current conduction mode control has been built and results of both prototype and MATLAB/Simulink are deployed to verify isolated single‐stage electric vehicle battery charger system's performance during dynamic and steady‐state conditions. [ABSTRACT FROM AUTHOR]

Background and Aims Materials and Methods Results Conclusions There is increased interest in utilizing dietary interventions to alter the progression of autoimmune diseases. These efforts are driven by associations of gut microbiota/metabolites with levels of short‐chain fatty acids (SCFAs). Propionate is a key SCFA that is commonly used as a food preservative and is endogenously generated by bacterial fermentation of non‐digestible carbohydrates in the gut. A thesis has suggested that a diet rich in propionate and other SCFAs can successfully modulate autoimmunity. Herein, we investigated the effect of long‐term administration of propionylated high‐amylose resistant starches (HAMSP) on the course of murine primary biliary cholangitis.Groups of female ARE‐Del mice were fed an HAMSP diet either before or after disease onset. A detailed immunobiological analysis was performed involving autoantibodies and rigorous T‐cell phenotyping, including enumeration of T‐cell subsets in the spleen, liver, intestinal intraepithelial lymphocytes and lamina propria by flow cytometry. Histopathological scores were used to assess the frequency and severity of liver inflammation and damage to hepatocytes and bile ducts.Our results demonstrate that a long‐term propionate‐yielding diet re‐populated the T‐cell pool with decreased naïve and central memory T‐cell subsets and an increase in the effector memory T cells in mice. Similarly, long‐term HAMSP intake reduced CD4+CD8+ double‐positive T cells in intraepithelial lymphocytes and the intestinal lamina propria. Critically, HAMSP consumption led to moderate‐to‐severe hepatocellular steatosis in ARE‐Del mice, independent of the stage of autoimmune cholangitis.Our data suggest that administration of HAMSP induces both regulatory and effector T cells. Furthermore, HAMSP administration resulted in hepatocellular steatosis. Given the interest in dietary modulation of autoimmunity and because propionate is widely used as a food preservative, these data have significant implications. This study also provides new insights into the immunological and pathological effects of chronic propionate exposure. [ABSTRACT FROM AUTHOR]