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

The paper presents a simple approach for analyzing switched reluctance motors (SRMs) operating under multiphase excitation. The analysis results in specific design coefficients [derived from the SRM flux and magnetomotive force (MMF) distributions that can be used in a methodology] to calculate the SRMs initial dimensions while taking into account the magnetic loading and electric loading. Finally, the approach enables comparison of SRM configurations for an application without performing complete designs. The magnetic loading (i.e., saturation) and torque of various SRM configurations designed using the proposed approach are verified through finite-element analysis (FEA).

Analysis, dimensional sizing and configuration comparison of switched-reluctance motors operating under multiphase excitation

The heat flux requirements of present power electronics systems are exceeding 100 W/cm2 and are predicted to reach the 1000 W/cm2 range in the near future. Spray cooling is a cooling technology that can provide such enormous cooling demands. Direct spray cooling of power devices (e.g., IGBTs) that are conventionally wire-bonded creates long-term reliability problems. So in order to achieve the expected future heat load demands and improve the reliability of the system there is a need for novel packaging methodologies. This paper reports on an innovative packaging methodology and a test vehicle that demonstrates the potential of spray cooling power electronics. This paper describes the proposed methodology as well as the spraying parameters that affect the cooling

A novel packaging methodology for spray cooling of power semiconductor devices using dielectric liquids

As a high-efficiency converter for photovoltaic power generation, the integrated boost series resonant (IBSR) converter includes three inductors, two capacitors, and one transformer, which occupy a significant volume. In order to further increase the power density, this paper proposes a novel passive integrated unit with the flexible multilayer foil integration technique for the above six passive components. First of all, the distributed electromagnetic component model of one new flexible three-layer film shows that the distributed parasitic capacitors formed by the insulation film are combined into the resonant capacitance. Then, the configuration of the proposed integrated unit is described in detail, and the electromagnetic analysis is given. Furthermore, the design procedure for the proposed integrated unit is demonstrated. Finally, a prototype for a 350 W IBSR converter has been built and the experimental results prove the validity of the proposed idea.

Passive Integration Using FMLF Technique for Integrated Boost Resonant Converters

A cascaded bridgeless totem-pole multilevel converter and its model predictive control (MPC) are proposed for the power interface of 400 V dc-powered data centers. Wide bandgap devices such as gallium nitride (GaN) or silicon carbide (SiC) MOSFETs with very low reverse recovery charge are utilized in the proposed totem-pole converter to reduce the switching loss. DC bus voltage error can be effectively mitigated by adopting the proposed MPC strategy when compared with a conventional proportional-integral (PI) control; the proposed MPC also exhibits smaller overshoot and much faster response when the load changes, and can operate at lower switching frequencies, thus further reducing switching losses. Furthermore, it is easier to balance the dc-bus voltages in each module using the proposed MPC control. The simulation and hardware-in-loop test results of conventional PI and proposed MPC controllers are presented to validate the effectiveness of the proposed converter and its control algorithm.

Cascaded bridgeless totem-pole multilevel converter with model predictive control for 400 V dc-powered data centers

Distributed generation (DG) units will become more common not only in microgrids but also conventional power grids due to advantages such as demand-side management capability, the potential for electricity generation at low costs, reduced congestion of transmission lines, and power quality improvements. Matrix converters (MCs) have been proposed as a power electronic interface (PEI) for interconnecting DG units based on microturbines that require efficient and reliable ac-ac converters. A novel current control strategy for indirect matrix converters (IMCs) used as the PEI for DG units operating at variable frequency is introduced. The proposed controller does not require sensing the DG unit output voltages and has the capability of regulating the IMC voltage in order to accommodate the commanded active power. The effectiveness of the proposed control approach is validated using a 5-kVA SiC-based IMC prototype to interface a variable-frequency voltage source with the grid.

Juan Carlos Balda

Papers

Analysis, dimensional sizing and configuration comparison of switched-reluctance motors operating under multiphase excitation

A novel packaging methodology for spray cooling of power semiconductor devices using dielectric liquids

Passive Integration Using FMLF Technique for Integrated Boost Resonant Converters

Cascaded bridgeless totem-pole multilevel converter with model predictive control for 400 V dc-powered data centers

New control strategy for indirect matrix converters operating in boost mode