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

This article presents an approach for the modulation of an asymmetric six-phase induction machine. The developed model is formed by two sets of three-phase stator windings that are displaced by 60 degrees. Since this kind of machines can have stator windings displaced with different angles this model also allows choosing another angle. Due to the fact that the induction machine was fully implemented in real coordinates, it is possible to simulate stator and rotor faults without being necessary to change system equations, only system parameters. The simulated results are used to validate the model.

New real coordinates model for an asymmetrical six-phase induction machine

Distributed Energy Resources (DER) has been widely introduced in distribution networks in response to the increase of environmental awareness of the consumers. The benefits with the use of DER are increased with network reconfiguration, but in some countries exists the impossibility of island operation as well as the obligation to buy all the electricity generated. These limitations, in a network fault situation, causes a waste of resources, because of the unavailability of the DER. On other hand, the location of DER connection under the context of the improvement of the reliability indexes has not been studied. Thus, this paper will propose a multi objective optimization of the location of DER connection considering the switching devices placement to increase network reliability and availability of DER, minimizing at the same time the investment in equipment in a no island operation environment. For the resolution of the proposed formulation, it will be used the multi objective algorithm NSGA-II (Fast Non-dominated Sorting Genetic Algorithm). The formulation of the problem also considers a composite index made up of DER and interruption duration. This approach is applied to a real utility distribution network, with the results presented and discussed.

/pdf/distributed-energy-resources-network-connection-considering-3038es2d5a.pdf

Distributed energy resources network connection considering reliability optimization using a NSGA-II algorithm

Three-phase STATCOM based on a single-phase current source inverter

This paper presents a four wire dual-buck inverter integrated in a photovoltaic system with grid support capabilities. In the context of smart-grids this kind of systems can play an important role. In this particular case the system will supply the ancillary services for unbalanced loads and reactive power compensation. A dual-buck inverter is adopted in order to ensure a higher reliability. This kind of inverter is characterized by the non-existence of shoot-through problems and by the possibility of the using power MOSFETs as active switches. The control system for the dual-buck inverter with the ancillary service functions is also presented. In order to verify the performance of this system several simulation results are presented and discussed.

A grid-connected PV system based on a four wire dual-buck inverter with ancillary services support

The perspective of Smart Grid developments brings a picture with active distribution networks having many distributed resources such as PV connected to the grid through inverters. The challenge for this future is so complex that the Smart Grid Coordination Group (SG-CG) is already considering for standardization in the new Use-Case cluster "Connect and active actor to the grid", the high level use case "Managing generation connection to the grid". This is considered as emerging necessary functionality of the "Distribution management system", to be subject of CEN/CENELEC standardization. This paper presents enabling solutions for these requests and proposes solutions for Automated Remote Grid Acceptance and Energy Services Tests using new concepts for the Smart Meter and for the inverters design. Results to sustain the proposals are also sustained by a case of simulation for a Grid Acceptance test — Fault Ride Through with reactive power and for an Energy Services Test proving interphase simetrization service.

V. Fernao Pires

Papers

New real coordinates model for an asymmetrical six-phase induction machine

Distributed energy resources network connection considering reliability optimization using a NSGA-II algorithm

Three-phase STATCOM based on a single-phase current source inverter

A grid-connected PV system based on a four wire dual-buck inverter with ancillary services support

Automating remote grid acceptance and energy services tests suited for large deployments of PV systems in active distribution networks