V. Fernao Pires

Bio: V. Fernao Pires is an academic researcher from INESC-ID. The author has contributed to research in topics: Inverter & Fault (power engineering). The author has an hindex of 18, co-authored 154 publications receiving 1457 citations. Previous affiliations of V. Fernao Pires include Technical University of Lisbon & University of Lisbon.

Multi-objective optimization with post-pareto optimality analysis for the integration of storage systems with reactive-power compensation in distribution networks

Abstract: The integration of energy storage systems in power distribution networks allows to obtain several benefits, such as, the minimization of energy losses, the improvement of voltage profile and the reduction of the energy costs. However, due to the high cost of these energy storage systems, this integration must be carefully applied. Thus, this work proposes the integration of energy storage systems based on a multiobjective optimization. The type of storage systems that is considered are the batteries. These systems require electronic power converters as an interface between the batteries and the grid. Thus, this work uses those converters to supply an ancillary service, more specifically, reactive power compensation. In this way, besides the peak shaving, the optimization approach will also consider the reactive-power compensation, allowing to improve the capital investment return of these systems. The reactive power compensation considers the maximum active power of the converter, to minimize the cost of the system. In consequence, when the energy storage system is at its maximum discharge mode, the reactive power compensation function will be inhibited. Since the multi-objective optimization generates a Pareto-optimal set with a large number of solutions, an approach to support the choice of the solution is also proposed. This approach considers a new post-Pareto analysis, which is based on the sum of the ranking differences. To demonstrate the applicability of the proposed approach, a case study using the 94-bus real test feeder is presented. Three scenarios tests are also presented for the post-pareto optimality analysis, each considering different weights for the objective functions. The results show that even for a specific case where the weights are assigned for each of the objective functions, more than one solution is obtained.

Photovoltaic electric vehicle chargers as a support for reactive power compensation

Abstract: As the penetration of electric vehicles increases the number of chargers for these vehicles are also increasing and therefore, will increase the electric energy grid consumption. To integrate these needs with the green energy, the use of electric chargers with a solar photovoltaic installation makes perfect sense. However, these charges can also be used for the support of the reactive power compensation. In this way, a photovoltaic electric vehicle charger that also supports reactive power compensation is presented. In order to keep the system as cheap as possible the apparent power of the system is not increased. If the photovoltaic panel is supplying energy to the electric vehicle or the vehicle is not charging at full power then the power converter connected to the power grid will compensate the reactive power. Furthermore, the batteries on board of the electric vehicle can be seen as part of the photovoltaic system, running not only as traction batteries but also as backup energy storage.

Fault-Tolerant Voltage-Source-Inverters for Switched Reluctance Motor Drives

Abstract: This paper proposes several modifications of the conventional Asymmetric Half-Bridge (ABH) topology for switched reluctance motor (SRM) drives with the aim of increasing its reliability to safety critical applications. This solution intends to achieve fast changing between main and standby redundant devices in fault-tolerant ABH topologies through the combination of mechanical commutators and semiconductors. With those modifications, the energy processing capability can be maintained for the most common failure modes. A survey of previously developed fault tolerant topologies for SRM drives and several aspects of failure modes, detection and isolation mechanisms are also included. The theoretical validity of one the proposed solutions is confirmed by several experimental results.

Induction motor broken bar fault detection based on MCSA, MSCSA and PCA: A comparative study

Abstract: The early failure detection of induction motors is considered very important in order to ensure their stability and high performance. Thus, condition monitoring of these motors are essential to ensure that. However, the effectiveness of the fault diagnosis depends on the quality of the fault features selection that is used in the adopted method. In this way, this paper will present a comparative study of three methods based on the electrical signal analysis. The first one is the most known method, motor current signature analysis (MCSA). Another method based on the analysis of spectral current, is the motor square current signature analysis (MSCSA), will also be used. Finally a third method based on principal component analysis (PCA) is also used. The performance of the methods is tested under different fault and load conditions. Experimental results are presented in order to compare the performance between the three methods.

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

Abstract: 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.<>

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

Abstract: 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.

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

Abstract: 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.