Analysis and control of dual-output LCLC resonant converters with significant leakage inductance

The analysis, design and control of fourth-order LCLC voltage-output series-parallel resonant converters for the provision of multiple regulated outputs, is described. Specifically, state-variable concepts are developed to establish operating mode boundaries with which to describe the internal behavior and the impact of output leakage inductance. The resulting models are compared with those obtained from SPICE simulations and measurements from a prototype power supply under closed loop control to verify the analysis, modeling, and control predictions

New battery model and state-of-health determination through subspace parameter estimation and state-observer techniques

This paper describes a novel adaptive battery model based on a remapped variant of the well-known Randles' lead-acid model. Remapping of the model is shown to allow improved modeling capabilities and accurate estimates of dynamic circuit parameters when used with subspace parameter-estimation techniques. The performance of the proposed methodology is demonstrated by application to batteries for an all-electric personal rapid transit vehicle from the Urban Light TRAnsport (ULTRA) program, which is designated for use at Heathrow Airport, U. K. The advantages of the proposed model over the Randles' circuit are demonstrated by comparisons with alternative observer/estimator techniques, such as the basic Utkin observer and the Kalman estimator. These techniques correctly identify and converge on voltages associated with the battery state-of-charge (SoC), despite erroneous initial conditions, thereby overcoming problems attributed to SoC drift (incurred by Coulomb-counting methods due to overcharging or ambient temperature fluctuations). Observation of these voltages, as well as online monitoring of the degradation of the estimated dynamic model parameters, allows battery aging (state-of-health) to also be assessed and, thereby, cell failure to be predicted. Due to the adaptive nature of the proposed algorithms, the techniques are suitable for applications over a wide range of operating environments, including large ambient temperature variations. Moreover, alternative battery topologies may also be accommodated by the automatic adjustment of the underlying state-space models used in both the parameter-estimation and observer/estimator stages

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

Matrix converters for sensorless control of PMSMs and other auxiliaries on deep-sea ROVs

The use of matrix converter technologies for the control of actuators and other auxiliaries onboard work-class, deep-sea, remotely operated vehicles (ROVs) is reported. Key requirements for such systems are the ability to sustain operation at high ambient pressures, up to 300 bar, commensurate with operation of ROVs at depths of 3000 m, and to minimise the number of external connections and cabling mass to improve reliability and reduce drag. Emphasis is given to 32 matrix converters for 3f–1f AC voltage/frequency for conversion control of system auxiliaries, with experimental results showing circuit functionality during pressure cycling consistent with typical operational duties, and the use of 33 matrix converters for control of actuators driven by brushless permanent magnet synchronous machines (PMSMs). A principal feature of the paper is the development of model-based sensorless control methodologies for driving PMSMs using matrix converters. In particular, it is shown that observer-based state estimation techniques normally employed for sensorless control of PMSMs using voltage source inverters, can be readily exported to matrix converter counterparts with minimal additional computational overhead. Experimental results from a 0.7 kW PMSM driven by a matrix converter, suitable for a subsea actuator pump, are included to demonstrate the ability of the sensorless techniques to provide reliable estimates of machine rotor position under transient load conditions, and the subsequent exploitation for matrix converter/motor combinations is discussed

The common PKD1 p.(Ile3167Phe) variant is hypomorphic and associated with very early onset, biallelic polycystic kidney disease

Biallelic PKD1 variants, including hypomorphic variants, can cause very early onset polycystic kidney disease (VEO-PKD). A family with unexplained recurrent VEO-PKD and neonatal demise in one dizygotic twin was referred for clinical testing. Further individuals with the putative hypomorphic PKD1 variant, p.(Ile3167Phe), were identified from the UK 100,000 genomes project (100 K), UK Biobank (UKBB), and a review of the literature. We identified a likely pathogenic PKD1 missense paternal variant and the putative hypomorphic PKD1 variant from the unaffected mother in the deceased twin but only the paternal PKD1 variant in the surviving dizygotic twin. Analysis of 100 K cases identified a second family with two siblings with similar biallelic inheritance who presented at birth with VEO-PKD and reached kidney failure in their teens unlike other affected relatives. Finally, a survey of 618 UKBB cases confirmed that adult patients monoallelic for PKD1 p.(Ile3167Phe) had normal kidney function. Our data reveals that p.(Ile3167Phe) is the second most common PKD1 hypomorphic variant identified and is neutral in heterozygosity but is associated with VEO-PKD when inherited in trans with a pathogenic PKD1 variant. Care should be taken to ensure that it is not automatically filtered from sequence data for VEO cases

Common variants near MC4R are associated with fat mass, weight and risk of obesity.

To identify common variants influencing body mass index (BMI), we analyzed genome-wide association data from 16,876 individuals of European descent. After previously reported variants in FTO, the strongest association signal (rs17782313, P = 2.9 x 10(-6)) mapped 188 kb downstream of MC4R (melanocortin-4 receptor), mutations of which are the leading cause of monogenic severe childhood-onset obesity. We confirmed the BMI association in 60,352 adults (per-allele effect = 0.05 Z-score units; P = 2.8 x 10(-15)) and 5,988 children aged 7-11 (0.13 Z-score units; P = 1.5 x 10(-8)). In case-control analyses (n = 10,583), the odds for severe childhood obesity reached 1.30 (P = 8.0 x 10(-11)). Furthermore, we observed overtransmission of the risk allele to obese offspring in 660 families (P (pedigree disequilibrium test average; PDT-avg) = 2.4 x 10(-4)). The SNP location and patterns of phenotypic associations are consistent with effects mediated through altered MC4R function. Our findings establish that common variants near MC4R influence fat mass, weight and obesity risk at the population level and reinforce the need for large-scale data integration to identify variants influencing continuous biomedical traits

Mineral nutrition of vegetable crops: XXV - Mineral nutrition of new zealand spinach plant (Tetragonia expansa Murr.)

The present work was carried out in order to study: a - the effect of omission and presence of the macronutrients and boron on the growth of the plants; b - deficiency symptoms of macronutrients, as well of boron; c - the effect of the deficiency of each nutrient on the chemical composition of the plants. Young spinach plants were grown in pots containing pure quartz sand. Several times a day the plants were irrigated by percolation with nutrient solutions. The treatments were: complete solution and deficient solution, in which each one of the macronutrients was omitted as well boron. Soon as the malnutrition symptoms appered, the plants were harvested and analysed chemically. - symptoms of malnutrition are easily observed for N, K, Ca and B. - symptoms of malnutrition for P, S and Mg are not easily identified. - the nutrient content, in dry matter, in deficient leaves and healthy leaves is:O trabalho teve como objetivo estudar alguns aspectos da nutrição mineral do espinafre (Tetragonia expansa Murr.) no que concerne: 1 - Efeitos da omissão dos macronutrientes e do boro, na obtenção de um quadro sintomatológico; 2 - Efeitos das carências na produção de matéria seca e composição química da planta. Mudas com trinta dias de idade foram transplantadas para soluções nutritivas carentes nos macronutrientes e/ou em boro. A coleta das plantas foi realizada quando os sintomas de deficiência se tornaram evidentes. No material seco procedeu-se a análise química. Os dados mostram que: 1 - os sintomas visuais de deficiência de N, K, Ca e B apresentam-se bem definidos; sendo que os de P, Mg e S são de difícil caracterização ; 2 - os teores dos nutrientes em plantas sadias e deficientes são