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

A system and method for variable power transfer in an inductive charging or power system. In accordance with an embodiment the system comprises a pad or similar base unit that contains a primary, which creates an alternating magnetic field. A receiver comprises a means for receiving the energy from the alternating magnetic field from the pad and transferring it to a mobile device, battery, or other device. In accordance with various embodiments, additional features can be incorporated into the system to provide greater power transfer efficiency, and to allow the system to be easily modified for applications that have different power requirements. These include variations in the material used to manufacture the primary and/or the receiver coils; modified circuit designs to be used on the primary and/or receiver side; and additional circuits and components that perform specialized tasks, such as mobile device or battery identification, and automatic voltage or power-setting for different devices or batteries.

System and method for inductive charging of portable devices

DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

/pdf/step-up-dc-dc-converters-a-comprehensive-review-of-voltage-6dlytctzg2.pdf

Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

In this paper, the principle of modularity is used to derive the different multilevel voltage and current source converter topologies. The paper is primarily focused on high-power applications and specifically on high-voltage dc systems. The derived converter cells are treated as building blocks and are contributing to the modularity of the system. By combining the different building blocks, i.e., the converter cells, a variety of voltage and current source modular multilevel converter topologies are derived and thoroughly discussed. Furthermore, by applying the modularity principle at the system level, various types of high-power converters are introduced. The modularity of the multilevel converters is studied in depth, and the challenges as well as the opportunities for high-power applications are illustrated.

Modular Multilevel Converters for HVDC Applications: Review on Converter Cells and Functionalities

This paper reviews the state of the art of field- programmable gate array (FPGA) design methodologies with a focus on industrial control system applications. This paper starts with an overview of FPGA technology development, followed by a presentation of design methodologies, development tools and relevant CAD environments, including the use of portable hardware description languages and system level programming/design tools. They enable a holistic functional approach with the major advantage of setting up a unique modeling and evaluation environment for complete industrial electronics systems. Three main design rules are then presented. These are algorithm refinement, modularity, and systematic search for the best compromise between the control performance and the architectural constraints. An overview of contributions and limits of FPGAs is also given, followed by a short survey of FPGA-based intelligent controllers for modern industrial systems. Finally, two complete and timely case studies are presented to illustrate the benefits of an FPGA implementation when using the proposed system modeling and design methodology. These consist of the direct torque control for induction motor drives and the control of a diesel-driven synchronous stand-alone generator with the help of fuzzy logic.

/pdf/fpga-design-methodology-for-industrial-control-systems-a-2kzb7fwd0q.pdf

FPGA Design Methodology for Industrial Control Systems—A Review

In this paper, an interleaved multiphase buck converter with minimum time control strategy for envelope amplifiers in high efficiency RF power amplifiers is proposed. The solution for the envelope amplifier is to combine the proposed converter with a linear regulator in series. High efficiency of envelope amplifier can be obtained through modulating the supply voltage of the linear regulator. Instead of tracking the envelope, the buck converter has discrete output voltage that corresponding to particular duty cycles which achieve total ripple cancellation. The transient model for minimum time control is explained, and the calculation of transient times that are pre-calculated and inserted into a lookup table is presented. The filter design trade-off that limits capability of envelope modulation is also discussed. The experimental results verify the fast voltage transient obtained with a 4-phase buck prototype.

/pdf/design-of-envelope-amplifier-based-on-interleaved-multiphase-2w7m08zouf.pdf

Design of envelope amplifier based on interleaved multiphase buck converter with minimum time control for RF application

The importance of modeling correctly multi-winding transformers is shown in this work. The inaccuracies of the classical model are described, and the advantages of a proposed distributed model are stated. Classic models do not provide accurate simulation results in those power configurations that are sensitive to the coupling of the multi-winding magnetic components. The accuracy and usefulness of the proposed distributed model are shown by comparing simulations and measurements in an actual multi-winding converter, which is very sensitive to the coupling between the auxiliary and power windings of the transformer.

Characterization of windings coupling in multi-winding magnetic components

Envelope simulation has proven to be an efficient tool for the analysis and simulation of resonant converters such as frequency controlled ballasts, series-parallel and parallel resonant converters and converters with piezoelectric transformers. In this work a nonlinear model for the envelope simulation of the half-wave rectifier and full wave rectifier is presented. The model accounts for the input capacitance effect on the rectifiers and can be easily implemented in a circuit oriented simulator. It is valid for transient, DC and AC analysis, what is especially useful for the controller design

Circuit Oriented Model of Rectifiers for Large Signal Envelope Simulation

The phase-shifted series-parallel resonant converter has shown to be a good candidate for high-voltage and high power applications. In some of those applications, the converter has to work under heavy and light load conditions that affect both its efficiency and operation conditions. This paper is focused on the analysis of two control strategies, commonly used to achieve ZCS in one branch, which provides the same steady-state driving for the switches but, depending on the load and frequency, their dynamic behavior is different and may also produce instability.

Analysis of the Internal Stability of Two Different Control Implementations of the Phase-Shifted Full-Bridge Resonant Converter

Rms voltage regulation may be an attractive possibility for controlling power inverters. Combined with a Hall Effect sensor for current control, it keeps its parallel operation capability while increasing its noise immunity, which may lead to a reduction of the Total Harmonic Distortion (THD). Besides, as voltage regulation is designed in DC, a simple PI regulator can provide accurate voltage tracking.

/pdf/current-mode-with-rms-voltage-and-offset-control-loops-for-a-3fevz95gpb.pdf

J.A. Cobos

Papers

Design of envelope amplifier based on interleaved multiphase buck converter with minimum time control for RF application

Characterization of windings coupling in multi-winding magnetic components

Circuit Oriented Model of Rectifiers for Large Signal Envelope Simulation

Analysis of the Internal Stability of Two Different Control Implementations of the Phase-Shifted Full-Bridge Resonant Converter

Current mode with RMS voltage and offset control loops for a single-phase aircraft inverter suitable for parallel and 3-phase operation modes