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.

/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

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

A single-phase reduced matrix converter is presented. This converter is used in solar PV farms to interface the string or even individual panel to a medium voltage grid. A high frequency transformer is used to step up the voltage. The operation of this converter is explained and then a controller for the single-phase embodiment of the converter is developed. Simulation results for a 50 kW, 600 Vdc to 4.16 kVLL converter are presented. The response of the controller is explored as well as the harmonic components of the ac output current, the high frequency transformer current, and the dc bus current.

http://ieeexplore.ieee.org/iel7/6780058/6785573/06785612.pdf

Dual active inverter for solar PV farms

Three-phase soft-switching inverters are promising in order to reduce the losses in the switching devices and to reduce the electromagnetic interference produced by severe di/dt and dv/dt, which enables the operation of the inverter at higher switching frequency. This work proposes a dc-side three-phase zero-voltage soft-switching inverter topology that can be sub-categorized under actively clamped resonant dc-link topologies. Moreover, a modified space-vector modulation scheme is proposed, such that all the devices operate under zero-voltage switching condition. Compared to other similar dc-link soft-switching topologies, the proposed topology does not require feedback from the inverter output currents to achieve soft-switching operation. Unlike conventional space-vector modulation techniques, the proposed modified space-vector modulation does not require to turn-on the top and/or the bottom three switches of the two-level inverter at the same time to implement the zero vectors, which allows a reduction of the effective commutating time of the two-level inverter switches by one-third, during a grid voltage cycle. The auxiliary capacitor is only charged to a fraction of the dc-bus voltage. Simulation and experimental results on a 10-kW and 100-kHz switching frequency lab-scale prototype are presented to demonstrate the validity and effectiveness of the proposed zero-voltage switching topology and modulation scheme on reducing the switching losses and electromagnetic interference.

DC-Side Soft-Switching Inverter With Modified Space-Vector Modulation Scheme

Soft-magnetic ribbon-based materials have been gaining popularity as their properties yield better efficiencies and power densities. Nevertheless, magnetic designs with these materials present a major shortcoming in the manufacturing process of tape-wound cut cores. Thus, this paper focuses on the critical issue of ribbon-based soft-magnetic cut-cores due to short-circuited layers along the cross-sectional area resulting from the cutting process. An etching process is proposed to overcome the interlamination short circuits of the magnetic cores. Microscopic view of the cross- sectional area demonstrates the effectiveness of etching process. Furthermore, two identical experimental medium- frequency transformers are built to study and compare the effects of the core etching on the transformer parameters. Open- and short-circuit impedance responses, and core loss characterization over frequency and flux density are presented before and after the etching process to establish the proper process to handle these tape-wound cut cores.

Etching Process to Reduce Interlamination Short Circuits and Core Loss Comparison for Tape-Wound Cut Cores

The authors evaluate two adaptive control methods for vector-controlled AC drives under parameter variations, namely a minimum variance controller (MVC) and a model reference exact-matching (MREM) method. They compare them to a nonadaptive model reference complementary controller (MRCC) and address their potential impact on designing PWM (pulse width modulation) inverters. Digital simulation results indicate that although all the methods considered had similar responses for nominal conditions, the MVC and MREM exhibited a higher performance than the MRCC under variations of the rotor time constant. However, the MVC PWM signal placed a more severe burden on the PWM stage. It is concluded that a comprehensive solution for the problem of parameter variations should include a combination of an identification method for the rotor parameters and adaptive control method to meet the desired specifications (rise time, bandwidth, speed range, etc.). >

http://ieeexplore.ieee.org/iel2/146/3637/00131238.pdf

A feasibility study of two adaptive-control methods for vector-controlled induction motor drives

Testing of new technologies before field deployment is crucial to gain acceptance by electric utilities, in particular, of distributed generation based on high power electronic modules The NCREPT 138 kV 6 MVA Test Facility at the University of Arkansas offers an advanced test platform designed to meet the needs of complex high power electronics testing for several distributed energy applications NCREPT could be also employed as a test platform for compliance of IEEE 1547 and UL 1741 standards This paper describes the center capabilities and some potential test applications such evaluation of grid-connected inverters supporting energy storage systems

Juan Carlos Balda

Papers

Dual active inverter for solar PV farms

DC-Side Soft-Switching Inverter With Modified Space-Vector Modulation Scheme

Etching Process to Reduce Interlamination Short Circuits and Core Loss Comparison for Tape-Wound Cut Cores

A feasibility study of two adaptive-control methods for vector-controlled induction motor drives

Testing of Power Electronic Modules for Distributed Systems at the National Center for Reliable Electric Power Transmission