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.

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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.

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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.

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FPGA Design Methodology for Industrial Control Systems—A Review

RF power amplifiers can save much energy if they are supplied with a variable voltage as described in the state of the art. The design of the power supply of these amplifiers is challenging since many requirements have to be accomplished: very low output voltage ripple; wide output voltage variation at kHz frequencies; fast load current steps; etc. A typical solution is the use of a multiphase dc-dc converter based on the buck topology. In this paper, we propose the use of digital control for these power supplies. The main advantage is that current loops are removed. The design of this control circuit and main trade-offs are discussed. The results obtained from a 240 W prototype show the advantages and the limitations of this proposal.

Digital control for power supply of a transmitter with variable reference

This work presents a summary about the state of the art in thermal modeling for magnetic components. The thermal problem is formulated in terms of physical concepts and mathematical equations and the procedures for carrying out the analysis of the problem are outlined. Different magnetic thermal models are studied according to the thermal effects that are modeled, geometries, coupling of the thermal and magnetic effects and application scope. Finally the thermal topics that are not modeled are emphasized and the different thermal models are compared from a practical point of view.

Thermal modeling for magnetic components: a survey

The use of zero-current-switched quasi-resonant converters (ZCS-QRCs) as power factor preregulators (PFPs) is studied The study is applicable to boost, buck-boost, flyback, SEPIC, and Cuk topologies The main conclusion is that the switching frequency variation range using a half-wave resonant switch is lower than that using a full-wave resonant switch if the load connected to the output is almost constant Moreover, using topologies with a transformer (flyback, SEPIC or Cuk), this variation range can be minimized choosing an adequate value of the normalized switching frequency at the peak of the sinusoidal input voltage However this range increases greatly when the load changes in the same manner In this case, a reduced switching frequency variation range is obtained using a full-wave switch However, this type of resonant switch decreases the efficiency because it handles reactive energy, and then a trade-off between switching frequency variation range and efficiency must be considered >

Analysis of the zero-current-switched quasiresonant converters used as power factor preregulators

Pulse width modulation (PWM) is a very common technique used in different applications, from the control of motors, switching power converters (power supplies), audio amplifiers or illumination systems. In some of those applications, the pulse frequency has increased so much in the last years that the resolution obtained with classical (counter) techniques is not enough. This paper explains some methods used for increasing the resolution of PWMs and proposes a new method based on the resources available in almost every FPGA nowadays.

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High Resolution Pulse Width Modulators in FPGA

This paper analyzes two different architectures for a hybrid power source comprising a PEM (polymer electrolyte membrane) fuel cell and a Li ion battery. The hybrid power source feeds the propulsion motor of an all electrical aircraft, the Boeing Fuel Cell Demonstrator. The architectures are an unregulated and a regulated hybrid power source. The regulation is achieved by means of a controllable series boost converter (SBC) connected in series with the fuel cell. Both architectures have been simulated, implemented and tested in the Boeing Fuel Cell Demonstrator Airplane.

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J.A. Cobos

Papers

Digital control for power supply of a transmitter with variable reference

Thermal modeling for magnetic components: a survey

Analysis of the zero-current-switched quasiresonant converters used as power factor preregulators

High Resolution Pulse Width Modulators in FPGA

Power balance of a hybrid power source in a power plant for a small propulsion aircraft