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.

PV generators combined with UPQC based on a dual converter structure

Abstract: In this paper a power converter topology where an Unified Power Quality Conditioner (UPQC) is combined with the photovoltaic generators is presented. This topology is based on a dual structure of the classical three-phase two level inverters. Thus, multilevel operation is achieved with the advantages of this type of inverters. Another feature of this structure is the higher reliability of the combined system. In fact, even with a fault in one of the inverters the system can still operate. Voltage and current controllers are also described. The current and voltage controllers are implemented in the synchronous rotating reference frame (dq0-axis). Several results are presented in order to verify the operation of the system under various conditions.

A neuro-fuzzy based system for fault detection and diagnosis of 3-phase PFC rectifier

Abstract: Fault diagnosis in PFC rectifiers is becoming more and more important in many industrial applications. PFC rectifiers allow high power factor operation in AC/DC conversion. This power converter is normally the first interface between the ac power system network and the electronic equipment. In this way a good diagnosis system can avoid unplanned standstill. Under this context, this work presents a method to detect and identify the open transistor circuit fault. The developed method has two major steps. First, the input line currents are converted into a new pattern representation. Second, a neuro-fuzzy algorithm will be used to identify the fault. Several simulation and experimental results are presented to show the effectiveness of the proposed approach.

Single-phase unity power-factor double buck rectifier: topology, operation and control

Abstract: This paper presents a new single-phase high power factor double buck rectifier. Unlike the buck rectifier, in which the output voltage is always smaller than the maximum input voltage, the proposed converter can operate with higher output voltages. The converter topology and operation are presented. A sliding mode control of the input current, capable of fast and robust current control, is also proposed. Using this control method, the converter presents high power factor and draws nearly sinusoidal input currents. A proportional integral (PI) controller is used to regulate the output voltage of the converter. This external voltage controller modulates the amplitude of the input current reference. Experimental results from a laboratory prototype are presented and discussed.

Multilevel power converter with a dual T-type three level inverter for energy storage

Abstract: In this work a new multilevel structure for interfacing energy storage systems is presented. This structure is based on a dual T-type three level voltage source inverter. These two power converters are connected to the grid by a three-phase transformer. This transformer has an open winding configuration on the side that connects to the multilevel power converter. This structure will present multilevel characteristics. A controller for this multilevel structure is also presented. The proposed topology and control system has been verified by numerical simulations. From the results of these simulations it is possible to verify the characteristics of the proposed structure.

A Water Pumping Photovoltaic Powered System Based on a DC-DC Converter with Dual Output and Extended Voltage Gain

Abstract: This paper has the purpose to present a non-isolated dual output DC-DC converter for a water pumping photovoltaic powered system. The proposed topology is based in a structure that integrates the traditional Sepic and Cuk converters. However, the topology was developed in order to only require a single power semiconductor switch. Besides that, it also characterized by an increment of the converter voltage static gain characteristic when compared with the traditional Sepic and Cuk topologies. Another interesting feature is that the voltage stress at the terminals of the power switch and diodes are reduced face to the converter output voltage. Another important feature is that the input current is continuous. Besides that, it was also developed to be adapted to the single-phase induction motor used in the water pumping. The photovoltaic system will be implemented through the use of a classical MPPT algorithm that will control the proposed DC-DC converter. The characteristics of the proposed DC-DC converter with dual output and extended voltage gain and global water pumping systems are verified through several simulation and experimental results.

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.