Juan Carlos Balda

Bio: Juan Carlos Balda is an academic researcher from University of Arkansas. The author has contributed to research in topics: Power module & Converters. The author has an hindex of 29, co-authored 180 publications receiving 3468 citations. Previous affiliations of Juan Carlos Balda include Clemson University & University of Arkansas at Little Rock.

A Survey of Systems to Integrate Distributed Energy Resources and Energy Storage on the Utility Grid

Abstract: Renewable distributed energy resources (DERs) will play a large role in the future energy infrastructure because of advantages like lower carbon imprints, lower fuel costs, and reduced power flows on transmission lines. The unreliability of many renewable DERs due to the intermittent nature of their supply, especially in the case of solar and wind generators, can be mitigated with energy storage that brings a host of additional benefits including load leveling, frequency control, and power quality compensation. One barrier to adoption of these technologies is the need for interfaces between the different voltage levels and waveforms produced by the various systems. This paper, which is tutorial in nature, examines several possible interfaces presented in the literature and provides a comparison between their advantages and disadvantages.

Smart grid applications of selected energy storage technologies

Abstract: Large-scale energy storage has recently been discussed as part of the future of the smart grid because of the many opportunities for improvement in the reliability and quality of the electric grid that can stem from their use. Information exchange from utility to consumer and vice versa makes it possible to send real-time signals regarding electricity prices and consumption. This enables many applications such as arbitrage, electric reserves, and load following to be served immediately by energy storage systems that are on the grid. For this reason, large-scale energy storage technologies must be implemented that have the ability to serve these applications. This paper examines three energy storage technologies that appear to be well suited for large-scale implementation: sodium-sulfur, vanadium-redox flow batteries, and lithium-ion batteries. These technologies were examined along with many other current technologies and chosen due to the potential to operate at grid-scales. Also, several of their potential applications are discussed.

Characterization of SiC JFET for Temperature Dependent Device Modeling

Abstract: Silicon Carbide (SiC) is considered the wide band gap semiconductor material that can presently compete with silicon (Si) material for power switching devices. Compact circuit simulation models for SiC devices are of utmost importance for designing and analyzing converter circuits; in particular, if comparisons with Si devices will be performed. The SiC power switching device structure and composition inevitably differs from those of conventional Si devices so as to harness the superiority of the material. The operational characteristics of the device thus are different from those of conventional Si devices. These characteristics cannot be accurately predicted by current Si power device models. Hence, the motivation to develop circuit simulation models for SiC devices. Moreover, SiC transistors have not been characterized as thoroughly as diodes. This paper characterizes SiC JFETs for the purpose of modeling and parameter extraction which can then be utilized in circuit simulations. The characterization is based on the dc (current-voltage) characteristic measurements using a curve tracer and on the ac (capacitance [impedance] — voltage) measurements using an impedance analyzer. Noting that characterization data for SiC JFETs are only available up to an ambient temperature of 250°C, the device is characterized from room temperature to 450°C demonstrating the high temperature operation of SiC JFETs. To this end, the devices were packaged in dedicated high temperature packages, and measurement fixtures were specially fabricated to withstand high ambient temperatures. The body diode buried in the evaluated SiC JFET is also characterized for potential synchronous rectifier applications.

Three-phase modeling for transient stability of large scale unbalanced distribution systems

Abstract: The transient stability of a distribution system containing rotating machines is usually evaluated by considering a symmetrical disturbance applied to a balanced network. Hence, most, if not all, available algorithms and stability programs use the bus admittance matrix for the positive sequence only. However, a typical distribution system may contain untransposed feeders, single-and/or three-phase unbalanced static shunt loads, single-and/or three-phase dynamic loads (such as induction motors), co-generators, transformers and capacitor banks. Furthermore, even if the network is balanced, unsymmetrical faults introduce unbalance. The effects of unbalances on the transient behavior of a single induction motor in a two-bus system using simultaneous nodal voltage equations has been recently investigated. It was concluded that a significant error may occur by replacing an unbalanced shunt load by an averaged balanced load and by assuming an unbalanced feeder to be an equivalent balanced feeder. This paper extends the previous investigation to large scale networks using a generalized three-phase bus admittance matrix [Ybus] method which takes care of the unbalances referred to above. Developing the three-phase [Ybus] itself is not new, but the novelty of the proposed method lies in the combination of the three-phase [Ybus] with the dynamics of rotating machines in transient stability studies of large networks using step-by-step integration of nonlinear differential equations. The method utilizes phase frame representation of network and machine elements. In order to be general, the computer program allows the user to include synchronous generators, induction motors, transformers, feeders and static loads.

Power-Semiconductor Devices and Components for New Power Converter Developments: A key enabler for ultrahigh efficiency power electronics

Abstract: In a world with an increasing penetration of widebandgap (WBG) semiconductor technology, the FEPPCON 2015 Session on New Power Devices and High Temperature focused on power-semiconductor devices and passive components (magnetic and dielectric materials) up through integration, for the purpose of refining appropriate power-electronics converters by 2025. An important goal was to identify those markets and applications where silicon technology will remain the preferred choice. The semiconductors are rarely the predominant failure mechanisms even in silicon modules; the failure mechanisms are usually either the passive components or the packaging. Thus, higher power densities afforded by using WBG semiconductors require those passives capable of operating at high temperatures and having high reliabilities. Presenters addressed the state of the art and future directions for magnetic cores, dielectric materials, and electronic packaging/integration. Finally, potential additional frontiers that merit research in a WBG world (such as new markets, capabilities, circuit architectures, and applications) were evaluated. The session was divided into four main groups: "WBG Technologies," "Silicon Technologies," "Passive Technologies," and "Power-Integration Technologies."

A Survey of Wide Bandgap Power Semiconductor Devices

Abstract: 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.

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

Abstract: 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.

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

Abstract: 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.

Energy Storage Systems for Transport and Grid Applications

Abstract: 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.