http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<<ETX>>

Multi-level conversion : high voltage choppers and voltage-source inverters

The main objective of this two-part state-of-the-art paper called “Recent Advances in the Design, Modeling, and Control of Multiphase Machines” is to present latest contributions in the multiphase machines' field. The first part of this paper focuses on the recent progress in the design, modeling, and control, whereas the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, particularly in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.

Recent Advances in the Design, Modeling, and Control of Multiphase Machines—Part II

Doubly fed induction generators (DFIGs), often organized in wind parks, are the most important generators used for variable-speed wind energy generation. This paper reviews the control systems for the operation of DFIGs and brushless DFIGs in wind energy applications. Control systems for stand-alone operation, connection to balanced or unbalanced grids, sensorless control, and frequency support from DFIGs and low-voltage ride-through issues are discussed.

Overview of Control Systems for the Operation of DFIGs in Wind Energy Applications

A sparse auto-encoder-based deep neural network approach for induction motor faults classification

In this paper, a new Fault Location method- ology for electrical power system networks is proposed. This methodology uses the α β space vector to identify and locate all different types of Faults (Phase-to-earth, Two- phase-to-earth, Phase-to-phase and Three-phase short- circuit). It is based on the modified version of Clarke's Transform, which is more suitable for real time implemen- tations with invariant power, which is known by Clarke- Concordia transformation. For data signals interpretation it is used the eigenvalue approach. The applied methodology is subdivided into several main steps: - Data acquisition, corresponding on three- phase current signals; - Mathematical treatment by the Clarke-Concordia Transformation; - Fault Identification, obtained by comparison of fault and pre-fault characteris- tic curves (on alpha-beta plan); - Fault location. The fault location is obtained from the relationship between distance and the eigenvalue of line currents matrix. Simulation results are presented showing the effective- ness of the proposed Algorithm for a correct Fault Loca- tion on distribution power system networks.

A NEW ACCURATE FAULT LOCATION METHOD USING α β SPACE VECTOR ALGORITHM

Teaching power electronics is a complex task. The classical approach is based on lectures and laboratories assisted by teachers. However, teaching power electronics it is not easy due to the student's motivation related to the difficult of this subject. In this way, this paper presents an approach to teach power electronics based on the students self learning. Instead of using the classical approach, students must develop a research work and a complete power converter prototype. Since students must have some background, this is a second course of power electronics. It is finally here that they clearly understand how a power converter works.

Self-learning as a tool for teaching power electronics

A simple position-sensorless method for the detection of rotor position of the wound-rotor induction machine in order to implement stator flux orientation is described and evaluated in this paper. The method is based on the comparison of the actual and the estimated rotor current using the classical model of this machine in the rotor reference frame. It is similar to the MRAS methodology, but uses a hysteresis comparator instead of a PI controller. In this way, the method doesn't need parameter determination for the controllers. Simulation results show that the method is appropriate for the vector control of the doubly fed induction machine.

Evaluation of a DFIG rotor position-sensorless detector based on a hysteresis controller

A new power conversion structure for a three-phase multilevel inverter is proposed in this paper. This structure uses a LeBlanc transformer and three single-phase voltage source inverters. The power converter topology has two single-phase outputs that connect to the LeBlanc transformer. This transformer allows deriving two-phase voltage to a three-phase source. This multilevel power conversion structure allows obtaining a five-level three-phase inverter. To control the proposed converter a sliding mode controller with a vectorial modulator was used. Simulation results of the proposed converter structure with their control system are presented. From the obtained results it possible to confirm the voltage multilevel waveforms and the effectiveness of the proposed control system technique.

Three-phase multilevel inverter based on LeBlanc transformer

In recent years the interest in Wireless Energy Transfer (WET) technology especially for electric vehicles batteries charging is rapidly growing. As a result of the increasing use of this technology in industrial and consumer electronic products, more concerns are raised about the electromagnetic compatibility since the WET systems produce electromagnetic emissions in the surrounding environment. Thus, the impact of the WET technology on other electrical and electronic equipment and in humans is the issue of high relevance. This paper presents a study related with the measurements of the electromagnetic emissions generated by a magnetic resonance wireless energy transfer (WET) system operating at kHz range of frequency.

V. Fernao Pires

Papers

A NEW ACCURATE FAULT LOCATION METHOD USING α β SPACE VECTOR ALGORITHM

Self-learning as a tool for teaching power electronics

Evaluation of a DFIG rotor position-sensorless detector based on a hysteresis controller

Three-phase multilevel inverter based on LeBlanc transformer

Study on electromagnetic emissions from wireless energy transfer