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The modular multilevel grid following string inverter (MMGFSI) has gained popularity in large rooftop solar photovoltaic power (PV) plant applications, with grid-integrated net metering facility. The performance of the standard PI controller-based MMGFSIs during grid load disturbances is not satisfactory due to the wide ripples, low dynamic performance, and low steady-state precision of the inverter current feedback regulation. This study proposes a repetitive control proportional-integral (RCPI) controller approach for the cascaded H-bridge (CHB) five-level grid following inverter to synchronize with the grid and satisfy enhanced power quality standards IEEE519 for large rooftop solar PV plant application system. Additionally, this proposed control topology performance has compared to PI controller-based MMGFSI’s and repetitive controller cascaded PI controller-based MMGFSI’s system. The proposed RCPI MMGFSI’s system performance has been tested on a PSIM simulation environment on a grid-connected, photovoltaic (PV) system with a diversity of linear and nonlinear load disturbances to show the viability and resilience of the suggested repetitive control strategy in practice. To provide the necessary carrier control signal for the sinusoidal pulse width modulation block (SPWM), a cycle delay has introduced in the RCPI feedback path. As a result, reducing grid-side harmonic distortion lowers the cost of the LCL filter connected to the inverter output This RCPI-based MMGFSI has 4.1 percent less overall harmonic distortion than the conventional PI controller-based MMGFSI and 0.21 percent less total harmonic distorted than repetitive cascaded PI controller-based MMGFSI’s system. Additionally, a hardware prototype has RCPI controller MMGFSI’s implemented to evaluate the five-level CHB MLI structure and switching topology. [ABSTRACT FROM AUTHOR]

The current investigation has identified the biomarkers associated with severity of disability and correlation among plethora of systemic, cellular and molecular parameters of intellectual disability (ID) in a rehabilitation home. The background of study lies with the recent clinical evidences which identified complications in ID. Various indicators from blood and peripheral system serve as potential surrogates for disability related changes in brain functions. ID subjects (Male, age 10 ± 5 yrs, N = 45) were classified as mild, moderate and severe according to the severity of disability using standard psychometric analysis. Clinical parameters including stress biomarkers, neurotransmitters, RBC morphology, expressions of inflammatory proteins and neurotrophic factor were estimated from PBMC, RBC and serum. The lipid peroxidation of PBMC and RBC membranes, levels of serum glutamate, serotonin, homocysteine, ROS, lactate and LDH-A expression increased significantly with severity of ID whereas changes in RBC membrane β-actin, serum BDNF, TNF-α and IL-6 was found non-significant. Structural abnormalities of RBC were more in severely disabled children compared to mildly affected ones. The oxidative stress remained a crucial factor with severity of disability. This is confirmed not only by RBC alterations but also with other cellular dysregulations. The present article extends unique insights of how severity of disability is correlated with various clinical, cellular and molecular markers of blood. This unique study primarily focuses on the strong predictors of severity of disability and their associations via brain-blood axis. [ABSTRACT FROM AUTHOR]