Multi-Objective Comparative Analysis of Active Modular Rectifier Architectures for a More Electric Aircraft

Aircraft electrification requires reliable, power-dense, high-efficient, and bidirectional rectifiers to improve the overall performance of existing aircrafts. Thus, traditional bulky passive rectifiers must be substituted by active rectifiers, satisfying the requirements imposed by up-to-date standards. However, several challenges are found in terms of power controllability, due to the standardized passive rectifier-based operating conditions. This work presents the implementation of an active rectifier modular architecture for aircraft applications. An analysis of the technical difficulties and limitations was performed and three innovative modular architectures are proposed and designed. In order to find the most suitable architecture, a comparison framework is proposed, focusing on efficiency, volume, and reliability parameters. From the comparative analysis, it can be concluded that the two-stage configuration architecture is a good solution in terms of semiconductor life expectancy and low volume. However, if converter redundancies are required, the single-stage with STATCOM configuration is an excellent trade-off between low volume, redundancy, and cost-effectiveness

Static Current Unbalance of Paralleled SiC MOSFET Modules in the Final Layout

Silicon Carbide (SiC) MOSFETs enable enhanced performance of power converters in several applications. Parallel connection of SiC MOSFETs become mandatory for medium power applications due to the current rate of existing modules. A balanced current sharing between paralleled MOSFETs is desired to maximize the power capability of each device, maximizing the power capability of the whole system. This work studies the static current unbalance of two paralleled 1200V-400A SiC MOSFET modules with individual gate driver. Experimental measurements are done focused on parasitic inductance caused by electromechanical layout

Simple voltage balancing method to protect series-connected devices experimentally verified in a 5L-MPC converter

This paper presents a solution for the voltage balance problem of the series-connected devices that can be applied to multilevel converters in which the series-connected devices need to block twice their switched voltage. The solution is based on two ideas, the control of the switching commands to achieve proper switching losses balance and the use of additional circuitry to achieve proper voltage balance during their blocking state. The proposed strategy is experimentally validated into a 5-level multipoint clamped full-scale converter. However, it can be used in any other converter topology in which the devices need to block twice their switched voltage

DC-link Voltage Balancing Strategy based on SVM and Reactive Power Exchange for a 5L-MPC Back-to-Back Converter for Medium Voltage Drives

The reduced capability of multilevel converters with more than one intermediate node to balance the dc-link capacitors voltage, as well as the lack of standard modulation methods to improve their balancing performance, makes these converter topologies unattractive for real power applications. This is especially true when the load demands active power. One of these topologies is the five-level multipoint clamped (5L-MPC) converter. The back-to-back (B2B) configuration of two 5L-MPC converters and the use of a space vector modulation (SVM) that exploits the voltage balancing capability of the redundant switching vectors extend the operation conditions range in which a proper voltage balance can be achieved. However, if practical modulation restrictions are considered (limitation of voltage steps, dead times, switching losses, etc.), the voltage balance cannot be achieved for all operation conditions. In this paper, an SVM which takes into account practical restrictions is proposed. In order to guarantee the voltage balance at any operation condition, the grid-side rectifier exchanges reactive power with the grid-side LCL filter. Thus, the voltage balance of the dc-link is guaranteed while a unity grid-side power factor is achieved. The proposed modulation scheme and the voltage balancing strategy are experimentally validated in a 6.6 kV 1.5 MW 5L-MPC B2B converter

Basics of Inductive Coupling and Role of Decoupling Capacitors

El acoplamiento electromagnético es el mecanismo con el que un circuito induce ruido o interferencia en otro circuito adyacente. Este mecanismo de acople genera Interferencias Electromagnéticas que degradan o incluso pueden interrumpir el funcionamiento de circuitos adyacentes. Sin embargo, a menudo, en los ámbitos académicos y profesionales de la electrónica de potencia, es poco común contar con los conocimientos suficientes para identificar y abordar esta problemática. Por lo tanto, la intuición juega un papel importante para prever y lidiar con esta problemática. En este artículo se describen los principios básicos de este mecanismo de acoplamiento y se proponen soluciones simples a este problema de interferencia electromagnética. Estas soluciones deben aplicarse ya desde la fase del diseño de cualquier equipo de electrónica. La problemática descrita y sus soluciones se validan experimentalmente en un circuito sencillo de prueba. Este artículo está orientado principalmente a alumnos y profesionales del ámbito de la electrónica de potencia y pretende describir de forma sencilla y experimentalmente la problemática asociada al acoplamiento inductivo

Design of a Solid-State Circuit Breaker for a DC Grid-Based Vessel Power System

Electric propulsion and integrated hybrid power systems can improve the energy efficiency and fuel consumption of different kinds of vessels. If the vessel power system is based on DC grid distribution, some benefits such as higher generator e ciency and lower volume and cost can be achieved. However, some challenges remain in terms of protection devices for this kind of DC grid-based power system. The absence of natural zero crossing in the DC current together with the fast and programmable breaking times required make it challenging. There are several papers related to DC breaker topologies and their role in DC grids; however, it is not easy to find comprehensive information about the design process of the DC breaker itself. In this paper, the basis for the design of a DC solid-state circuit breaker (SSCB) for low voltage vessel DC grids is presented. The proposed SSCB full-scale prototype detects and opens the fault in less than 3 us. This paper includes theoretical analyses, design guidelines, modeling and simulation, and experimental results

Electric Technology in Wind Turbines from a Dialectic Perspective

Wind turbines have been used by many groups of humans for many centu-ries. Wind turbines have allowed groups of humans to perform many different tasks in the past (grinding grain, pumping water, etc.). However, only a century and a half ago, they began to be used to convert the energy captured from wind into electric energy. Moreover, only approximately twenty-five years ago, we started to introduce on a massive scale the energy generated from wind turbines into the electric networks of most developed countries in the world for regular consumption. According to 2017 statistics, approximately 12 percent of the electric energy consumed in the EU is pro-duced by wind turbines. Despite the fact that wind turbines generally appear quite similar externally—i.e., a three-blade structure, a nacelle, a tower, etc.—if we care-fully examine the electric technology used within them, we find quite a wide range of technologies for energy conversion, which is a key issue in wind turbine technology. Hence, this paper adopts a dialectic perspective towards analyzing and understanding why several electric technologies coexist in wind turbine technology. We explain the specific factors that have influenced different wind turbine manufacturers to adopt dif-ferent electric technologies across the last twenty-five years. We show how their actions and the technological directions that have followed have been mutually codetermined, resulting in a technological evolution that has produced today’s wind turbine variety

Medium voltage-high power converter topologies comparison procedure for a 6.6kV Drive Application using 4.5kV IGBT Modules

This paper presents a general comparison procedure for medium voltage - high power multilevel converter topologies and semiconductors, which is mainly based on analyzing the performance limits of the converters output characteristics such as the output voltage, current, active power, efficiency, etc. Afterwards, the general procedure is applied to compare some of the most relevant converter topologies oriented to a 6.6 kV drive application supplying quadratic torque loads and using 4.5 kV IGBT modules. The paper concludes evaluating the comparison factors of the different converter topologies and selected semiconductors obtained by the proposed procedure. The proposed procedure can potentially be extrapolated to any desired application framework