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.

Intelligent and adaptive on-line direct electromagnetic torque estimator for switched reluctance motors based on artificial neural networks

Abstract: Torque estimation is an important task in the implementation of controllers for electric motor drives. In the case of switched reluctance motors (SRM), the computation technique should account for the nonlinearity of the magnetic material and the variations of the flux-linkage characteristics with rotor position and current level. Also, it is essential to adapt to the characteristics of the individual SRM (due to manufacturing deviations) when requiring high accuracy in this task. This paper presents a technique based on artificial neural networks (ANN) that estimates the electromagnetic torque developed by learning the characteristics of the SRM drive system using online measurements. The technique is then illustrated by applying it in simulations for predicting the electromagnetic torque.

Enhancing power quality on distribution systems with Fault-Current Limiters

Abstract: High levels of power quality are required in electric power systems to ensure safe and continuous operation for most loads. Voltage sags, one of the most critical power quality problems that utilities and customers alike may face, are short voltage-reduction events representing probably one of the main causes of costly shutdowns in companies.

A grid interface for distributed energy resources with integrated energy storage using a high frequency AC link

Abstract: A multiport converter with a high frequency (hf) ac bus is proposed for use as a distributed energy resource (DER) to grid interface with an integrated energy storage system (ESS). The combination of DER and ESS allows the DER to provide load following, load leveling, power quality compensation, voltage and frequency control, and spinning reserve, as well as savings on deferred installation of new transmission lines and centralized power plants, reduced loads on existing transmission lines, increased grid security and reliability, and the potential to adjust power delivery to take advantage of the energy market. The use of the hf-ac bus allows the boost and dc-hf ac conversion functions to be combined into a single converter and reduces the size of the transformer and passives. The proposed design allows independent control of each of the DER and ESS inputs, allowing for modular design and ease of expansion for the system. The digest explores several of the challenges of the design and presents theoretical and simulated waveforms for one of the operating conditions. Seven possible operating conditions are identified, and the applicability of each operating condition is determined when the system is used for power generation, load leveling, and spinning reserve.

A nano-composite polyamide imide passivation for 10 kV power electronics modules

Abstract: High current and voltage handling capabilities are desired in many high-performance power electronic modules. One of the main challenges when integrating a power module is having a high-voltage insulation material that is reliable at all operating temperatures. In this work, the use of a polyamide imide (PAI) material as the high-voltage passivation for the power electronic modules was investigated. The power modules were integrated with a two-step passivation-encapsulation process using the PAI material. The fabricated modules were tested up to 10 kV to evaluate the material insulation properties.

Efficient Multiphase Cooling System for Large Area Using Multiple Jet/Spray

Abstract: Jet/spray cooling is a way of efficiently removing heat from a hot surface like in the back plate for high power electronic devices. In the present work, a close loop liquid jet/spray setup with a novel effluent/spent liquid removal system is established for large area cooling. A 4×4 nozzle array is used to generate the spray/jet targeting the heat source area of 4 (2×2) cm2 . Flourinert FC-72™ is used as coolant liquid. The thermal performance data for multi-jet/spray cooling in a closed and confined system are obtained at various liquid temperatures and flow rates. The experimental work illustrates the multi-jet cooling system can reach critical heat fluxes up to 101 W/cm2 . The results showed that the heat flux is increased with liquid sub-cooled temperature and flow rates in single phase as well as in phase change zone. It is further observed that the critical heat flux (CHF) increases with liquid sub-cooled temperature and flow rates.Copyright © 2009 by ASME

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.