Theses

Lastest theses presented:

High Efficiency Sensorless Fault Tolerant Control of Permanent Magnet Assisted Synchronous Reluctance Motor

Michalski, Tomasz Dobromir

Supervisors: Romeral Martinez, Jose Luis

Jury

President: Muñoz Hernández, Germán Ardul

Secretary: Moreno Eguilaz, Juan Manuel

Vocal: Rolak, Michal

Date: October 2021

Overview:

In the last decades, the development trends of compact and high-efficiency electric drives on the motor side have focused on permanent magnet synchronous machines (PMSM) equipped with magnets based on rare earth elements. However, permanent magnet components dramatically impact motor construction cost. This aspect has become even more critical due to price volatility for rare earth elements. This is why the permanent magnet assisted synchronous reluctance motor (PMaSynRM) concept has been taken into consideration as it offers comparable torque density and efficiencies similar to PMSM, albeit at a lower price credited for the use of magnets made of ferrite compounds. Although PMaSynRM drive is very complex due to non-linear inductances resulting from deep cross saturation effects, this is also true for polyphase PMSM motors that have gained a lot of attention in recent years, in which the power is proportionally divided by the largest number of phases. Also, they offer fault-tolerant operation while one or more phases are idle due to machine, inverter, or sensor faults. However, the number of phases further increases the overall complexity of the modeling and control design. It is clear then that a combination of multiphase with the PMaSynRM concept has potential benefits, but hinders standard modeling methods and drive system development techniques.This thesis consists of detailed modeling, control design and implementation of a five phase PMaSynRM drive for normal healthy and fault tolerant open phase applications.

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Development of the future generation of smart high voltage connectors and related components for substations, with energy autonomy and wireless data transmission capability

Kadechkar, Akash

Supervisors: Riba Ruiz, Jordi Roger; Moreno Eguilaz, Juan Manuel

Jury

President: Pallarès Marzal, Josep

Secretary: Ortega Redondo, Juan Antonio

Vocal: Jordà I sunuy, Xavier

Date: October 2020

Overview:

The increased dependence on electricity in modern society makes the reliability of power transmission systems a key point. This objective can be achieved by continuously monitoring the parameters of the electrical network, whereby possible failure modes can be predicted in advance. It can be done using existing Information and Communication Technologies (1CT) and Internet of Things (loT) technologies that include instrumentation and wireless communication systems, thus forming a wireless sensor network (WSN). Electrical connectors are among the most critical parts of any electrical system and therefore can act as nodes of such a VVSN. Therefore, the fundamental objective of this thesis is the design, development and experimental validation of a self-powered IOT solution for real-time monitoring of the health status of a high-voltage substation connector and related components of the electrical substation. This new family of power connectors is called SmartConnector and incorporates a thermal energy harvesting system that powers a microcontroller that controls a transmitter and various electronic sensors to measure the connector's temperature, current, and electrical contact resistance (ECR).

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Active Gate Drivers for High-Frequency Application of SiC MOSFETs

Paredes Camacho, Alejandro

Supervisors: José Luis Romeral & Vicente Sala Casellas

Jury

President: Perpiñà Giribert, Xavier

Secretary: Moreno Eguilaz, Juan Manuel

Vocal: Saavedra Ordoñez, Harold

Date: July 2020

Overview:

The trend in the development of power converters is focused on efficient systems with high power density, reliability and low cost. The challenges to cover the new power converters requirements are mainly concentered on the use of new switching-device technologies such as silicon carbide MOSFETs (SiC). SiC MOSFETs have better characteristics than their silicon counterparts; they have low conduction resistance, can work at higher switching speeds and can operate at higher temperature and voltage levels. Despite the advantages of SiC transistors, operating at high switching frequencies, with these devices, reveal new challenges. The fast switching speeds of SiC MOSFETs can cause over-voltages and over-currents that lead to electromagnetic interference (EMI) problems. For this reason, gate drivers (GD) development is a fundamental stage in SiC MOSFETs circuitry design. The reduction of the problems at high switching frequencies, thus increasing their performance, will allow to take advantage of these devices and achieve more efficient and high power density systems. This Thesis consists of a study, design and development of active gate drivers (AGDs) aimed to improve the switching performance of SiC MOSFETs applied to high-frequency power converters. Every developed stage regarding the GDs is validated through tests and experimental studies. In addition, the developed GDs are applied to converters for wireless charging systems of electric vehicle batteries. The results show the effectiveness of the proposed GDs and their viability in power converters based on SiC MOSFET devices.

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