Design of Converters for PV System Under Partial Shading Conditions

This paper presents a maximum power generation with the interconnection of photovoltaic modules under partially shaded and/or mismatching conditions. The partial shading condition reduces power level of each module. The reduction in power due to the partial shading will be compensated by the bidirectional converter. The proposed system consisting of two and three PV modules connected in series under partial shading conditions which are capable of increasing the power levels up to 50% compared to conventional by-pass diode structure. In general ‘n’ number of modules connected in series so that the maximum power gain will be expected to (100/n) %. This is achieved by developing the new control strategy in which the correct adjustment of converter duty ratio under partially shading conditions. The novel control scheme is developed by using analysis of the power converters. The proposed scheme was verified in MATLAB/SIMULINK

Haptoglobin2-2 phenotype is an additional risk factor of retinopathy in type 2 diabetes mellitus

Aims: The aim of this study was to investigate the association between haptoglobin (Hp) phenotypes and risk of the development of diabetic retinopathy (DR) in patients of type 2 diabetes mellitus. Materials and Methods: This cross-sectional study included 45 normotensive type 2 diabetic patients (duration more than 5 years) admitted in the hospital divided into two groups (with and without DR) on the basis of fundus examination by direct ophthalmoscopy. Serum samples of all patients were subjected for Hp phenotyping by polyacrylamide gel electrophoresis. Results: DR was associated significantly in diabetic patients with Hp2-2 phenotype (79.31%) than diabetic patients with Hp2-1 phenotype (43.75%) and Hp2-2 had higher odds ratio (OR) for DR in univariate analysis (OR 4.929, [95% confidence interval [CI] (1.297-18.733)], P = 0.016) and multivariate analysis (OR 7.704 [95% CI (0.887-66.945)], P = 0.064). Furthermore, Hp2-2 was associated significantly with severe forms of DR. Conclusion: Hp2-2 phenotype is associated with susceptibility to DR showing a graded risk relationship to the number of Hp2 alleles. Determination of Hp phenotype may be useful in the risk assessment and management of DR