http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

High-frequency-link (HFL) power conversion systems (PCSs) are attracting more and more attentions in academia and industry for high power density, reduced weight, and low noise without compromising efficiency, cost, and reliability. In HFL PCSs, dual-active-bridge (DAB) isolated bidirectional dc-dc converter (IBDC) serves as the core circuit. This paper gives an overview of DAB-IBDC for HFL PCSs. First, the research necessity and development history are introduced. Second, the research subjects about basic characterization, control strategy, soft-switching solution and variant, as well as hardware design and optimization are reviewed and analyzed. On this basis, several typical application schemes of DAB-IBDC for HPL PCSs are presented in a worldwide scope. Finally, design recommendations and future trends are presented. As the core circuit of HFL PCSs, DAB-IBDC has wide prospects. The large-scale practical application of DAB-IBDC for HFL PCSs is expected with the recent advances in solid-state semiconductors, magnetic and capacitive materials, and microelectronic technologies.

Overview of Dual-Active-Bridge Isolated Bidirectional DC–DC Converter for High-Frequency-Link Power-Conversion System

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

Energy storage systems (ESSs) are enabling technologies for well-established and new applications such as power peak shaving, electric vehicles, integration of renewable energies, etc. This paper presents a review of ESSs for transport and grid applications, covering several aspects as the storage technology, the main applications, and the power converters used to operate some of the energy storage technologies. Special attention is given to the different applications, providing a deep description of the system and addressing the most suitable storage technology. The main objective of this paper is to introduce the subject and to give an updated reference to nonspecialist, academic, and engineers in the field of power electronics.

Energy Storage Systems for Transport and Grid Applications

Low-pass ac filters are frequently adopted in microgrid power electronic interfaces that convert distributed generators' dc power to ac power because most of today's distribution grids have ac voltages. Compared to a simple L filter, higher-order filters, such as LC or LCL filters, are preferred due to their more effective reduction of switching-frequency harmonics and smaller sizes. As the converter power ratings increase, resonance problems caused by the higher-order filters challenge microgrid stability. This paper investigates a microgrid resonance propagation circuit model, which includes paralleling multiple converters with their filters. Each converter has a power rating in the MW range. The converter control design is illustrated and hardware experimental results validate the design and modeling.

Resonance propagation modeling and analysis of AC filters in a large-scale microgrid

Indirect matrix converters (IMCs) inherently provide more opportunity for higher power per volume densities than traditional back-to-back converters (BBCs). The use of new wide bandgap power semiconductor devices, like those based on silicon carbide (SiC), for different power converter applications is becoming more prevalent due to advantages realized at the system level when compared to conventional silicon (Si) devices. The small footprint and low switching losses of SiC devices allow for an increase in the power density of the power converter, but packaging them into a single module is a challenge. As power converters with higher volumetric densities are being pursued, an IMC based on SiC semiconductor devices provides a more than viable solution for exceeding current power density limits. The development of a 15kW, 480Vrms IMC based on a single power module realized using SiC 1200V, 50A MOSFETs and 1200V, 20A Schottky barrier diodes (SBDs) to achieve a system level power density of 13 kW/liter is presented in this paper. The power stage is implemented in an interleaved input/output phase leg arrangement to reduce parasitic inductances in the critical dc-bus path. Experimental results are given to demonstrate the functionality of the proposed IMC system.

Realization of a SiC module-based indirect matrix converter with minimum parasitic inductances

The design of a 150-kW high-frequency three-port transformer (TPT) for a triple active bridge (TAB) converter application is the focus of this paper A non-tradeoff inclusive design methodology for custom-core transformers is proposed Classic transformer design methodologies based on complex trade-offs mechanisms require significant effort to adjust the design for commercially available pre-sized cores The proposed design is based on the development of a set of design equations that allows to select the core dimensions and the turns numbers for the windings that best accomplish the transformer specifications Experimental evidence verifying the proposed theoretical design methodology is presented in this work

150-kW Three-Port Custom-Core Transformer Design Methodology

A novel method for selecting the most suitable converter for photovoltaic (PV) panels is given in this paper. The innovations reside on the analysis of energy efficiency; where, in addition to the converter power efficiency, the extraction power efficiency and the energy power distribution are considered. It is shown that the conventional method of selecting the converter based on its power efficiency is not always accurate in terms of the harvested energy. Two interleaved flyback converters with different designs and control and switching strategies are compared; one is controlled by duty cycle and the other is controlled by frequency. The result of the conventional method of comparison suggests that the design controlled by frequency is about 2 % more efficient that the design controlled by duty cycle. However, the proposed method of the comparison shows that the design controlled by duty cycle delivers to the load 12.5 MJ more per year, that represents a 1.9 % increase in energy efficiency, showing that the conventional method is not the best in terms of the harvested energy.

A novel method to compare converters for PV applications based on energy efficiency

The growth of demand invariably lead to higher and higher fault currents, and as a consequence protection devices must have higher ratings The integration of distributed energy resources further complicates protection schemes, especially those that assume a radial distribution scheme and power flowing in only one direction These conditions generate an increasing demand for fault current limiters to keep fault currents within the ratings of existing protection equipment as well as to minimize the impact of distributed generation on the grid during faults However, placement of protection equipment must be carefully considered in order to keep them cost effective and to prevent the limiters themselves from disrupting existing protective measures This paper explores several placement and coordination guidelines, as well as provides simulations of fault current limiters placed in substations with ring bus and double bus configurations, respectively

Juan Carlos Balda

Papers

Resonance propagation modeling and analysis of AC filters in a large-scale microgrid

Realization of a SiC module-based indirect matrix converter with minimum parasitic inductances

150-kW Three-Port Custom-Core Transformer Design Methodology

A novel method to compare converters for PV applications based on energy efficiency

Fault Current Limiter Placement Strategies and Evaluation in Two Example Systems