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Analysis and Design of a Single-Phase Tapped-Coupled-Inductor Boost DC–DC Converter
Michael Njoroge Gitau,Fredrick Mukundi Mwaniki,Ivan W. Hofsajer 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4
A single-phase tapped-inductor boost converter has been proposed previously. However, detailed characterization and performance analysis were not conducted. This paper presents a detailed characterization, performance analysis, and design expressions of a single-phase tapped-coupled-inductor boost converter. Expressions are derived for average and RMS input current as well as for RMS input and output capacitor current ripple. A systematic approach for sizing the tapped-coupled inductor, active switch, and output diode is presented; such approach has not been reported in related literature. This study reveals that sizing of the inductor has to be based on current ripple requirement, turns ratio, and load. Conditions that produce discontinuous inductor current are also discussed. Analysis of a non-ideal converter operating in continuous conduction mode is also conducted. The expression for the voltage ratio considering the coupling coefficient is derived. The suitability of the converter for high-voltage step-up applications is evaluated. Factors that affect the voltage boost ratio are also identified. The effects of duty ratio and load variation on the performance of the converter are also investigated. The theoretically derived characteristics are validated through simulations. Experimental results obtained at a low power level are included to validate the analytical and simulation results. A good agreement is observed among the analytical, simulation, and experimental results.
Analysis and Design of a Single-Phase Tapped-Coupled-Inductor Boost DC-DC Converter
Gitau, Michael Njoroge,Mwaniki, Fredrick Mukundi,Hofsajer, Ivan W. The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4
A single-phase tapped-inductor boost converter has been proposed previously. However, detailed characterization and performance analysis were not conducted. This paper presents a detailed characterization, performance analysis, and design expressions of a single-phase tapped-coupled-inductor boost converter. Expressions are derived for average and RMS input current as well as for RMS input and output capacitor current ripple. A systematic approach for sizing the tapped-coupled inductor, active switch, and output diode is presented; such approach has not been reported in related literature. This study reveals that sizing of the inductor has to be based on current ripple requirement, turns ratio, and load. Conditions that produce discontinuous inductor current are also discussed. Analysis of a non-ideal converter operating in continuous conduction mode is also conducted. The expression for the voltage ratio considering the coupling coefficient is derived. The suitability of the converter for high-voltage step-up applications is evaluated. Factors that affect the voltage boost ratio are also identified. The effects of duty ratio and load variation on the performance of the converter are also investigated. The theoretically derived characteristics are validated through simulations. Experimental results obtained at a low power level are included to validate the analytical and simulation results. A good agreement is observed among the analytical, simulation, and experimental results.
Risk Management in the Clinical Laboratory
Sarah W Njoroge,James H Nichols 대한진단검사의학회 2014 Annals of Laboratory Medicine Vol.34 No.4
Clinical laboratory tests play an integral role in medical decision-making and as such must be reliable and accurate. Unfortunately, no laboratory tests or devices are foolproof and er- rors can occur at pre-analytical, analytical and post-analytical phases of testing. Evaluating possible conditions that could lead to errors and outlining the necessary steps to detect and prevent errors before they cause patient harm is therefore an important part of laboratory testing. This can be achieved through the practice of risk management. EP23-A is a new guideline from the CLSI that introduces risk management principles to the clinical labora- tory. This guideline borrows concepts from the manufacturing industry and encourages laboratories to develop risk management plans that address the specific risks inherent to each lab. Once the risks have been identified, the laboratory must implement control pro- cesses and continuously monitor and modify them to make certain that risk is maintained at a clinically acceptable level. This review summarizes the principles of risk management in the clinical laboratory and describes various quality control activities employed by the laboratory to achieve the goal of reporting valid, accurate and reliable test results.