Methodologies for the design of LCC voltage-output resonant converters

Abstract: The paper presents five structured design methodologies for third-order LCC voltage output resonant converters. The underlying principle of each technique is based on an adaptation of a FMA equivalent circuit that accommodates the nonlinear behaviour of the converter. In contrast to previously published methods, the proposed methodologies explicitly incorporate the effects of the transformer magnetising inductance. Furthermore, a number of the methodologies allow the resonant-tank components to be specified at the design phase, thereby facilitating the use of standard off-the-shelf components. A procedure for sizing the filter capacitor is derived, and the use of error mapping, to identify parameter boundaries and provide the designer with a qualitative feel for the accuracy of a proposed converter design, is explored

Note on the Relativistic Thermodynamics of Moving Bodies

We employ a novel thermodynamical argument to show that, at the macroscopic level,there is no intrinsic law of temperature transformation under Lorentz boosts. This result extends the corresponding microstatistical one of earlier works to the purely macroscopic regime and signifies that the concept of temperature as an objective entity is restricted to the description of bodies in their rest frames. The argument on which this result is based is centred on the thermal transactions between a body that moves with uniform velocity relative to a certain inertial frame and a thermometer, designed to measure its temperature, that is held at rest in that frame.Comment: To be published in J. Phys. A. A few minor corrections have been made to the earlier version of this articl

Health Report

This Plan for Health is an unusual undertaking in two respects. It is part of the Go To 2040 regional master plan along with other human services components that have, historically, been outside the purview of planners, who are usually more concerned with issues such as land use, transportation, and solid waste disposal. And the planning horizon covers three decades, providing a rare opportunity for health planners to engage in truly long range planning. Health is more than medical care: a variety of factors determine the health of individuals and a community. These "underlying determinants" include demographic composition, income and poverty, employment, social status, cultural beliefs and practices, level of educational attainment, environmental conditions, genetics, individual behaviors, and public health measures, in addition to the quality and utilization of health care services.Most planning efforts, which attempt to affect community health, deal only with public health and medical services delivery, even though the other factors are known to have a greater influence on community and individual health. This plan approaches the challenge differently; it focuses on the underlying determinants of health and moves beyond the narrower focus that health planners and public health officials traditionally take. This report identifies the connections that education, land use, transportation, food and hunger, civic engagement, workforce, and the economy have with health, and it focuses on strategies and interventions that can be pursued in these sectors to improve health throughout this region

A describing function for resonantly commutated H-bridge inverters

Abstract—The paper presents the derivation of a describing function to model the dynamic behavior of a metal oxide semiconductor field effect transistor-based, capacitively commutated H-bridge, including a comprehensive explanation of the various stages in the switching cycle. Expressions to model the resulting input current, are also given. The derived model allows the inverter to be accurately modeled within a control system simulation over a number of utility input voltage cycles, without resorting to computationally intensive switching-cycle level, time-domain SPICE simulations. Experimental measurements from a prototype H-bridge inverter employed in an induction heating application, are used to demonstrate a high degree of prediction accuracy over a large variation of load conditions is possible using the simplified model

Observer based feedback control of 3rd order LCC resonant converters

The paper considers specific issues related to the design and realisation of observer-based feedback of isolated output voltage for resonant power converters. To provide a focus to the study, a 3rd order LCC converter is employed as a candidate topology. It is shown that whilst resonant converters nominally operate at high switching frequencies to facilitate the use of small reactive components, by appropriate pre-conditioning of non-isolated resonant-tank voltages and currents, the resulting observer can be implemented at relatively low sampling frequencies, and hence, take advantage of low-cost digital hardware. Experimental results are used to demonstrate the accuracy of observer estimates under both transient and steady-state operating conditions, and to show operation of the observer as part of a closed-loop feedback system where the LCC resonant converter is used as a regulated power supply

Cyclic-averaging for high-speed analysis of resonant converters

Abstract—The paper describes the development and application of a cyclic-averaging technique for the rapid analysis of high-order resonant power converters. To provide a focus to the paper, particular emphasis is given to a 3rd-order LCC voltage output converter topology. The proposed methodology predicts steady-state voltages and currents throughout the circuit, and provides estimates of the stresses on the resonant circuit components. State-space simulations and experimental results from a 350 V-input/150 V-output converter are used to demonstrate a prediction accuracy comparable with time-domain integration-based techniques is achievable, while requiring only 1/10,000th of the computation time. In addition, a comparison with Spice simulation results shows that cyclic averaging provides commensurate predictions of voltage and current stresses on the resonant circuit components. Issues arising from the stray capacitance associated with the resonant inductor, and the corresponding sensitivity of the predicted output voltage, are also considered

Tunable BODIPY derivatives amenable to "click" and peptide chemistry

Novel azido- and amino- functionalised fluorescent probes based on the BODIPY framework have been developed. The probes can be easily and cheaply synthesised, exhibit the highly desirable BODIPY fluorescent properties, and are amenable to “click” and peptide chemistry methodologies. These probes provide a stable and readily available tool amenable for the visualisation of both solution and solid supported events

Molecular dynamics simulation study of elastic properties of HMX

Journal ArticleAtomistic simulations were used to calculate the isothermal elastic properties for b-, a-, and d-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The room-temperature isotherm for each polymorph was computed in the pressure interval 0≤p≤10.6 GPa and was used to extract the initial isothermal bulk modulus Ko and its pressure derivative using equations of state employed previously in experimental studies of the b-HMX isotherm

Temperature dependent shear viscosity coefficient of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX ): a molecular dynamics simulation study

Journal ArticleEquilibrium molecular dynamics methods were used in conjunction with linear response theory and a recently published potential-energy surface [J. Phys. Chem. B 103, 3570 (1999)] to compute the liquid shear viscosity and self-diffusion coefficient of the high explosive HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) over the temperature domain 550-800 K. Predicted values of the shear viscosity range from 0.0055 Pa *s at the highest temperature studied up to 0.45 Pa *s for temperatures near the melting point

Molecular dynamics simulations of HMX crystal polymorphs using a flexible molecule force field

Journal ArticleMolecular dynamics simulations using a recently developed quantum chemistry-based atomistic force field [J. Phys. Chem. B 103 (1999) 3570] were performed in order to obtain unit cell parameters, coefficients of thermal expansion, and heats of sublimation for the three pure crystal polymorphs of octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazocine (HMX). The predictions for β-, α-, and δ-HMX showed good agreement with the available experimental data