Study on Enhancement of Output of Grid Tied PV Systems under Symmetrical and Asymmetrical Faults

High performance grid-tied inverters havestringent control requirements both under steady-state andunder transient conditions. Many different control systemscan be applied to grid-tied inverters. High quality voltageand current are required when PV generator is connectedto grid utility. To this, multilevel inverters can be used asconnection interface. Efficiency enhancement scheme of amultilevel grid-connected inverter for renewable energygeneration systems is researched in detail. This paper haswidely reviewed the existing MLIs came to under thecategories of Symmetric, Asymmetric, Hybrid and SingleDC source based structures, realizing high-quality outputwaveform being specially designed for medium to highpowerapplications. Thereby a detailed investigation havebeen done for each topology and category. Furtherenhancement can be done by using MPPT algorithms

Mapping the human genetic architecture of COVID-19

The genetic make-up of an individual contributes to the susceptibility and response to viral infection. Although environmental, clinical and social factors have a role in the chance of exposure to SARS-CoV-2 and the severity of COVID-191,2, host genetics may also be important. Identifying host-specific genetic factors may reveal biological mechanisms of therapeutic relevance and clarify causal relationships of modifiable environmental risk factors for SARS-CoV-2 infection and outcomes. We formed a global network of researchers to investigate the role of human genetics in SARS-CoV-2 infection and COVID-19 severity. Here we describe the results of three genome-wide association meta-analyses that consist of up to 49,562 patients with COVID-19 from 46 studies across 19 countries. We report 13 genome-wide significant loci that are associated with SARS-CoV-2 infection or severe manifestations of COVID-19. Several of these loci correspond to previously documented associations to lung or autoimmune and inflammatory diseases3,4,5,6,7. They also represent potentially actionable mechanisms in response to infection. Mendelian randomization analyses support a causal role for smoking and body-mass index for severe COVID-19 although not for type II diabetes. The identification of novel host genetic factors associated with COVID-19 was made possible by the community of human genetics researchers coming together to prioritize the sharing of data, results, resources and analytical frameworks. This working model of international collaboration underscores what is possible for future genetic discoveries in emerging pandemics, or indeed for any complex human disease