There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This International Myeloma Working Group consensus updates the disease defi nition of multiple myeloma to include validated biomarkers in addition to existing requirements of attributable CRAB features (hypercalcaemia, renal failure, anaemia, and bone lesions). These changes are based on the identifi cation of biomarkers associated with near inevitable development of CRAB features in patients who would otherwise be regarded as having smouldering multiple myeloma. A delay in application of the label of multiple myeloma and postponement of therapy could be detrimental to these patients. In addition to this change, we clarify and update the underlying laboratory and radiographic variables that fulfi l the criteria for the presence of myeloma-defi ning CRAB features, and the histological and monoclonal protein requirements for the disease diagnosis. Finally, we provide specifi c metrics that new biomarkers should meet for inclusion in the disease defi nition. The International Myeloma Working Group recommends the implementation of these criteria in routine practice and in future clinical trials, and recommends that future studies analyse any diff erences in outcome that might occur as a result of the new disease defi nition.

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International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma.

Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

/pdf/a-review-of-single-phase-improved-power-quality-ac-dc-2pm6h4zjxq.pdf

A review of single-phase improved power quality AC-DC converters

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

/pdf/light-emitting-diodes-ubzde6g9qc.pdf

Light-emitting diodes

Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.

Comprehensive Study of Single-Phase AC-DC Power Factor Corrected Converters With High-Frequency Isolation

This paper presents the analysis and design of an LED driver based on the series-resonant converter (SRC) and on the self-oscillating command circuit (SOCC). The use of SRC provides a reduction of the low frequency (LF) ripple in the LEDs' current, originated by the voltage ripple in the output of the power factor correction (PFC) stage (bus voltage ripple). The attenuation of the ripple transmission from the bus voltage to the LEDs' current achieves some desired goals: (1) reduction of the bulk capacitance used at the output of the PFC stage, enabling the employment of long-life film capacitors, and (2) increasing of the efficiency of the LED driver because of the low switching losses of the series-resonant converter. The SOCC stamps on the LED driver the low-cost, simplicity, and robustness features. In order to avoid any mismatch between the SRC LF current ripple reduction design guidelines and the SOCC design, a design methodology is presented. Experimental results from a self-oscillating series resonant converter to supply a 10 Watts LED lamp are presented, validating the feasibility of the developed methodology and the proposed analysis.

Self-oscillating series-resonant led driver applied to reduce low-frequency current ripple transmission

This paper presents an electronic ballast for driving high intensity discharge (HID) lamps with low frequency square waveform from a dc supply. From the dc source (e.g., PFC rail), a flyback arrangement is inserted into a switching structure whose output provides low frequency voltage yet avoiding instability issues. Proposal's main advantage is the use of one single choke of simple assembly and only two active switches for current control and inversion. Converter design for DCM is presented in this work, besides an equivalent circuit from a control point of view. Small signal ac model is obtained and a feedback control loop is designed, based upon frequency response stability and performance analysis. HID dynamics is inserted into converter model, with feedback directly implemented. A prototype is presented and described in detail, consisting of a complete power and sensing circuit fully referenced to the switches common ground proposal. For design conformity, experimental and simulation results from Matlab and PSIM are presented, as well as discussions about the converter feasibility.

Modified Flyback for HID Lamp Supply: Design, Modeling, and Control

The T5 fluorescent lamp is the first linear lamp type to be controlled only by electronic ballasts, due to its high lamp voltage and the requirement of an end-of-life detection circuit. Its efficient behavior and compactness has pushed it into the leading edge of new fluorescent lighting projects. This paper investigates the response of the T5 lamps to magnetically-controlled electronic ballasts, also exploring new magnetic regulator topologies. Experimental results for the Master TL5 HE 14W and 21W from Philips are reported.

Magnetic regulator topologies for dimmable electronic ballasts

In this paper the analysis of the class E amplifier with two current sources used to implement a high-power-factor electronic ballast for fluorescent lamps is presented. The circuit is based on a class E amplifier with two current sources, one of them implemented using the main voltage and the other by means of a bulk capacitor charged from the resonant tank of the class E amplifier. Based on the performed analysis a 300 kHz electronic ballast for a 32 W compact fluorescent lamp was designed and tested.

https://ieeexplore.ieee.org/iel5/7171/19288/00891410.pdf

Analysis of the class E amplifier with two current sources used as a high-power-factor electronic ballast for fluorescent lamps

The main disadvantage of single-stage electronic ballasts is the high stress that should withstand at least one of the converter switches. This drawback narrows the application range of this kind of solutions to lamps below 70 W due to the high-cost transistors needed. In the present paper, a new four-switch single-stage topology is described. This topology comes from the integration of a full-bridge resonant inverter and a double-switch buck converter. Low-cost transistors can be used for supplying lamps up to 250 W thanks to the low stress on all switches. Also, a new low-cost self-oscillating control circuit is proposed and analyzed. The basic design guidelines are also given in this paper and experimentally verified using a laboratory prototype implemented for a 125 W high-pressure-mercury lamp.

J.M. Alonso

Papers

Self-oscillating series-resonant led driver applied to reduce low-frequency current ripple transmission

Modified Flyback for HID Lamp Supply: Design, Modeling, and Control

Magnetic regulator topologies for dimmable electronic ballasts

Analysis of the class E amplifier with two current sources used as a high-power-factor electronic ballast for fluorescent lamps

A new discharge lamp ballast based on a self-oscillating full-bridge inverter integrated with a buck-type PFC circuit