Showing papers by "Juan Carlos Balda published in 2021"

A Review of Current Research Trends in Power-Electronic Innovations in Cyber–Physical Systems

Abstract: In this article, a broad overview of the current research trends in power-electronic innovations in cyber–physical systems (CPSs) is presented. The recent advances in semiconductor device technologies, control architectures, and communication methodologies have enabled researchers to develop integrated smart CPSs that can cater to the emerging requirements of smart grids, renewable energy, electric vehicles, trains, ships, the Internet of Things (IoT), and so on. The topics presented in this article include novel power-distribution architectures, protection techniques considering large renewable integration in smart grids, wireless charging in electric vehicles, simultaneous power and information transmission, multihop network-based coordination, power technologies for renewable energy and smart transformer, CPS reliability, transactive smart railway grid, and real-time simulation of shipboard power systems. It is anticipated that the research trends presented in this article will provide a timely and useful overview to the power-electronics researchers with broad applications in CPSs.

A Modular Switching Position With Voltage-Balancing and Self-Powering for Series Device Connection

Abstract: Medium-voltage converters, especially those making use of SiC devices, require high common-mode voltage immunity and resilience against associated high dv/dt across multiple isolation barriers. A truly modular and common-mode immune switching position could be beneficial for these applications. The design of a modular switching position is presented here for a series connection of power semiconductors with voltage-balancing and self-powered-gate capabilities. The designs of the voltage-balancing and self-powered circuits are described, followed by simulations and testing of a 3.3-kV switching position formed by two 1.7-kV SiC MOSFETs in series. Testing results demonstrate the ability of the proposed switching position to balance the voltage across series-connected MOSFETs even if the gate signals of the series-connected devices are not perfectly synchronized while powering themselves directly from the OFF-state voltage across them. In addition, a startup circuit for the switching position is proposed and experimentally confirmed.

A Three-Level Isolated AC–DC PFC Power Converter Topology With a Reduced Number of Switches

Abstract: The main objective of this research work is to develop a new low-cost isolated three-level ac–dc power converter topology with a reduced number of switches. Existing three-level converter topologies change ac power to dc power while maintaining requirements set by international standards for power conversion. These types of converters have significant conduction losses due to high currents in the low-voltage side and high costs, mainly when using several active devices in series or in parallel to achieve high-voltage and high-power levels. The proposed topology replaces the conventional three-level converters in the secondary side by only two controlled devices and four diodes while still maintaining the basic functionality of a three-level converter. Furthermore, simulation results for a 25-kW case study and experimental results on a 900-W scale-down prototype demonstrate the feasibility of the proposed ideas.

Inductor and Transformer-Coupled Magnetic Structure for Zero-Ripple dc-dc Ćuk Converter

Abstract: An inductor and transformer-coupled integrated magnetics (IM) structure is proposed to achieve zero inductor current ripple in a dc-dc isolated Cuk converter. The structure provides an easy-to-build approach, overcoming the necessity of a cumbersome trade-off calibration for the air gaps and number of turns, as required in the conventional IM approach used for the Cuk dc-dc topology. The validity and effectiveness of the proposed magnetic structure is demonstrated by simulation and experimental results on dc-dc isolated Cuk converter prototype.

Design of Nanocrystalline Medium-Voltage Medium-Frequency Three-Phase Transformers for Grid-Connected Applications

Abstract: This paper presents the design of a three-phase three-limb high-efficiency medium-voltage medium-frequency transformer with an integrated leakage layer using ribbon-based nanocrystalline cores for three-phase grid-connected applications. The design methodology is based on a custom-core approach developed by a series of design equations that allow the user to select a design that best fits the transformer specifications. A 150kVA 10-kHz 5-kV-to-400-V three-phase three-limb transformer is designed to validate the proposed design method. In addition, a series of experimental characterisation tests are conducted to measure the performance of the design according do the theoretical performance.

Construction and Testing of a 13.8 kV, 750 kVA 3-Phase Current Compensator Using Modular Switching Positions

Abstract: Availability of high-voltage power modules based on silicon carbide (SiC) is enabling the realization of multilevel topologies to solve a variety of issues in power distribution systems. However, the relatively low voltage ratings of currently-available semiconductor devices increase the complexity of the required solutions. Stacking lower-cost and lower-voltage devices to derive a higher-voltage switch can help reduce system complexity at the expense of more a complex switching position. Thus, this stacking solution comes with its own set of challenges. This paper presents the design and experimental results for an 11-level 13.8 kV neutral-point-clamped flying-capacitor converter that uses stackable switching positions for three-phase current compensation in a distribution system. The converter is successfully used for direct grid-connection and upstream current compensation with a 4.16 kV LL grid.

A Medium-Voltage SiC Flying Capacitor Converter Design for 25-kV Distribution Systems

Abstract: Grid-connected medium-voltage (MV) distribution flexible ac transmission systems (D-FACTS) can be used to perform many functions such as improving the quality of electric power in distribution systems. This paper provides a design methodology for a 2-MVA MV D-FACTS based on a flying-capacitor converter (FCC) topology for three-phase four-wire 25-kV distribution systems. By considering the breakdown and utilization voltages of the available power modules as the main design factor, 10-kV silicon-carbide (SiC) MOSFET half-bridge power modules was chosen with 73% utilization factor. Then, sizing of the flying capacitor cells, dc-bus capacitance, and output LCL filter was performed. Thereafter, the required parts for these components were selected to show the feasibility of fabrication. The power losses of switching modules were investigated for one phase of the converter. Finally, the envisioned MV-FCC functions of compensating for three-phase unbalanced currents and injecting reactive power complementing switched capacitor banks are illustrated through simulations.

Evaluation of Single-Phase PV Smart Inverter Functions in Unbalanced Residential Distribution Systems

Abstract: Rooftop single-phase PV smart inverters in residential distribution systems are becoming more common throughout the United States. As a result, utilities are experiencing increases in the numbers of operations for voltage regulators and on-load tap changers under certain operating conditions for high PV penetration levels which may lead to reduced maintenance intervals. However, PV smart inverters can be controlled under different functions or operating modes with some potentially reducing the number of operations of voltage regulators and thus, increasing maintenance intervals. To this end, three selected functions of PV smart inverters are evaluated on a case study based on a 13.8-kV modified IEEE 37-bus system controlled under conservation voltage reduction and integrated Volt/VAr using EPRI OpenDSS™ software package to demonstrate that some functions do positively assist in voltage regulation and reactive power control.