https://iopscience.iop.org/article/10.1088/2515-7647/ab77a2/pdf

Silicon carbide color centers for quantum applications

Vertical gallium nitride (GaN) power devices are enabling next-generation power electronic devices and systems with higher energy efficiency, higher power density, faster switching, and smaller form factor. In Part I of this review, we have reviewed the basic design principles and physics of building blocks of vertical GaN power devices, i.e., Schottky barrier diodes and p-n diodes. Key topics such as materials engineering, device engineering, avalanche breakdown, and leakage mechanisms are discussed. In Part II of this review, several more advanced power rectifiers are discussed, including junction barrier Schottky (JBS) rectifiers, merged p-n/Schottky (MPS) rectifiers, and trench metal–insulator–semiconductor barrier Schottky (TMBS) rectifiers. Normally- OFF GaN power transistors have been realized in various advanced device structures, including current aperture vertical electron transistors (CAVETs), junction field-effect transistors (JFETs), metal–oxide–semiconductor field-effect transistors (MOSFETs), and fin field-effect transistors (FinFETs). A detailed analysis on their performance metrics is provided, with special emphasis on the impacts of key fabrication processes such as etching, ion implantation, and surface treatment. Lastly, exciting progress has been made on selective area doping and regrowth, a critical process for the fabrication of vertical GaN power devices. Various materials characterization techniques and surface treatments have proven to be beneficial in aiding this rapid development. This timely and comprehensive review summarizes the current progress, understanding, and challenges in vertical GaN power devices, which can serve as not only a gateway for those interested in the field but also a critical reference for researchers in the wide bandgap semiconductor and power electronics community.

Vertical GaN Power Devices: Device Principles and Fabrication Technologies—Part II

A review on high-frequency pulsed arc welding

Even though achieving carbon-free and reduced NOx emission transportation is a prevailing goal, the aviation industry is in its infancy to arrive at passenger class all-electric aircraft (AEA) properly operating over commercial missions. Challenges are mainly associated with components of the aircraft electric power system (EPS). Considering today’s technologies, power electronics components are not capable to sustain tens of megawatts of required power during the take-off and meet the aviation limits in terms of size, weight, and cost at the same time. State-of-the-art electrochemical energy units (EEU), including battery, fuel cell, and supercapacitor, cannot provide the 25-30 MW thrust power needed for the take-off, and electrical circuit breakers are not able to clear a fault in a large AEA propulsion system, and multi-megawatt electric drives/motors can barely be found being able to provide 2-3 MW thrust power so that they can be employed in a distributed propulsion architecture. Taking mentioned challenges into account, this article aims to tackle challenges associated with protection devices, EEUs, and electric machines in passenger class AEA, and present promising solutions using an envisioned MVDC ±5 kV EPS for an AEA, all-electric NASA N3-X aircraft. Based on findings and discussions made through the article, the authors conclude that although technology advancements are essential in all research areas, high voltage wide-bandgap electrical circuit breakers, Li-air and Li-S batteries with >1000 kW/kg specific power, and multi-megawatt superconducting electric machines will turn a commercialized passenger class AEA into reality within the next 20-30 years.

Components of Electrical Power Systems in More and All-Electric Aircraft: A Review

This article presents a novel system to connect a three-phase doubly fed induction generator (DFIG) to a dc-microgrid. The proposed system uses a three-leg rectifier at each side of the stator windings, in an open-end winding configuration. Usually, these legs are composed of insulated gate bipolar transistors (IGBTs). To reduce the number of controlled switches and costs, one of the rectifiers has its IGBT switches replaced by diodes. The converters operating principles, pulsewidth modulation, power control, and zero-sequence current minimization strategies are discussed. The proposed system is compared with two conventional systems in terms of current harmonic distortion, torque ripple, and semiconductor losses. Simulations and experiments were also performed, showing steady-state and transient results for a 0.56-kW DFIG operating at constant torque. Finally, it was verified that the proposed system maintains balanced voltages and currents over the DFIG stator windings, with no significant torque oscillations.

Dual Converter Connecting Open-End Doubly Fed Induction Generator to a DC-Microgrid

Silicon (Si) power devices have dominated the world of Power Electronics in the last years, and they have proven to be efficient in a wide range of applications. But high power, high frequency and high temperature applications require more than Si can deliver. With the advance of technology, Silicon Carbide (SiC) and Gallium Nitride (GaN) power devices have evolved from immature prototypes in laboratories to a viable alternative to Si-based power devices in high-efficiency and high-power density applications. SiC and GaN devices have several compelling advantages: high-breakdown voltage, high-operating electric field, high-operating temperature, high-switching frequency and low losses. This paper provides a general review on the properties of these materials comparing some performance between Si and SiC devices for typical power electronics applications. Based on studied information, line of progress and the current state of developing, SiC seems to be the most viable substitute in high power and high temperature applications in the mid-term of Si, due to the fact that the GaN is still used in a reduced number of applications.

SIC power devices in power electronics: An overview

This paper presents a sensorless rotor position detection method, that uses a stator flux estimation based on a parallel observer. A closed-loop rotor speed estimation from the rotor position is also proposed. The operating principles of the Doubly-Fed Induction Generators (DFIG) based on wind generation systems and the field oriented control strategy are discussed. Finally, experimental results are presented, showing transient responses for a $0.56 \mathrm {k}\mathrm {W}$ DFIG operating at unity power factor. The proposed method has excellent performance even near synchronous speed, without using any initial rotor position information.

Sensorless Rotor Position Detection of Doubly-Fed Induction Generators for Wind Energy Applications

/pdf/three-phase-to-single-phase-generation-system-based-on-2ixbavew9i.pdf

Three-phase to single-phase generation system based on doubly-fed induction generator

This paper presents a Finite Control Set Model Predictive Control (FCS-MPC) method applied to a Half-Controlled Boost Rectifier (HCBR) that can be used in variable-speed permanent magnet generator. Performance comparison of the system using conventional controls and predictive control methods, in order to regulate the input currents, is accomplished. Results show that the predictive control presents better performance than hysteresis and linear control with pulse width modulation.

Predictive Control for a Half-Controlled Boost Rectifier

In this paper a three-phase flyback-push-pull ZVSPWM DC-DC converter is proposed. The converter owns the advantages of three-phase topologies with compact passive devices, low conduction power losses, higher power density and smaller filters. The converter uses a full three-phase bridge and a clamping capacitor in the transformer primary side, allowing the reuse of the energy from leakage inductances and the reduction of the eletromagnetic interference. These characteristics make this converter suitable for many applications, such as telecommunications power supply, battery chargers, and renewable power systems. A detailed analysis of the converter is provided, including theoretical waveforms, a description of the topological stages, a design example and mathematical expression for the voltage gain in continuos conduction mode of region R 3 . In order to validate the theoretical analysis was presented a design example and the simulation results for an output power of 1000 W with an input voltage of 50 V, an output voltage of 400 V and a switching frequency of 40 kHz.

Filipe V. Rocha

Papers

SIC power devices in power electronics: An overview

Sensorless Rotor Position Detection of Doubly-Fed Induction Generators for Wind Energy Applications

Three-phase to single-phase generation system based on doubly-fed induction generator

Predictive Control for a Half-Controlled Boost Rectifier

A Three-Phase Flyback-Push-Pull ZVS-PWM Converter