In the modern world of technology, the cascaded DC-DC converters with multiple output configurations are contributing a dominant part in the DC distribution systems and DC micro-grids. An individual DC-DC converter of any configuration exhibits complex non-linear dynamic behavior resulting in instability. This paper presents a cascaded system with one source boost converter and three load converters including buck, Cuk, and Single-Ended Primary Inductance Converter (SEPIC) that are analyzed for the complex non-linear bifurcation phenomena. An outer voltage feedback loop along with an inner current feedback loop control strategy is used for all the sub-converters in the cascaded system. To explain the complex non-linear dynamic behavior, a discrete mapping model is developed for the proposed cascaded system and the Jacobian matrix's eigenvalues are evaluated. For the simplification of the analysis, every load converter is regarded as a fixed power load (FPL) under reasonable assumptions such as fixed frequency and input voltage. The eigenvalues of period-1 and period-2 reveal that the source boost converter undergoes period-2 orbit and chaos whereas all the load converters operate in a stable period-1 orbit. The proposed configuration eliminates the period-2 and chaotic behavior from all the load converters and is also validated using simulation in MATLAB/Simulink and experimental results.

No abstract

In women of reproductive age bacterial vaginosis is a most common polymicrobialdisease and is the leading reason for vaginal discharge in this age group. Additionally itis further linked with sizeable disease burden of community problem in terms of infectiouscomplications. Clindamycin vaginal cream and metronidazole vaginal gel are effective in themanagement of vaginal infections caused by multi bacteria. Objectives: To compare thetherapeutic efficacy of Metronidazole vaginal gel and clindamycin vaginal cream as modality oftreatment for bacterial vaginosis. Study Design: Randomized control trial. Setting: Departmentof Obstetrics and Gynaecology, Unit-3 Jinnah Hospital Lahore. Period: Six months from 02-05-2011 to 01-11-2011. Material & Methods: A total of 300 patients were included in this study.They were divided into two groups. Group A received metronidazole vaginal gel (5 g dailyfor 7 days) while group B administered with clindamycin vaginal cream (5g daily for 7 days).Results: Mean age of the patient was observed 34.3+3.5 and 32.9+ 2.1 years in group –A andB respectively. Vaginal discharge was absent in 104 patients (69.3%) from group A and 127(84.7%) from group-B. Absence of clue cells on microscopy revealed in 112 patients (74.7%)from group A and 137 patients (91.3%) from group B. Absence of amine odour found in 116patients (77.3%) of group A and 134 patients (89.3%) of group B. Significant difference wasfound between two groups with p value of 0.006 in respect of efficacy. Conclusion: Clindamycinvaginal cream is more effective in comparison to Metronidazole vaginal gel for the treatment ofbacterial vaginosis.