IPS - ESTS – DEE - Comunicações em congressos
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- Fault detection and diagnosis technique for a SRM drive based on a multilevel converter using a machine learning approachPublication . Amaral, Tito G.; Pires, Vítor; Foito, Daniel José Medronho; Pires, A. J.; Martins, J. F.SRM drives based on multilevel converters is now a solution well accepted due to their interesting features like extended voltage range and capability to fault tolerance. However, one aspect that is fundamental to ensure fault tolerance or preventive maintenance is the fault detection and diagnosis of failures in power semiconductors. In this way, in this paper it is presented a new diagnostic method for the failure of those semiconductors in asymmetric neutral point clamped converters. The proposed method will be based on the development of specific patterns that are associated to each semiconductor and fault type. The procedures presented here are based on the image identification of the currents patterns in the multilevel converter that allow the identification of distinct fault type. The pattern recognition system uses visual-based efficient invariants features for continuous monitoring of multilevel converter The proposed method will be verified through several tests in which were used a simulation tool and an experimental prototype.
- A Fault Diagnosis Scheme Based on the Normalized Indexes of the Images eccentricity for a Multilevel Converter of a Switched Reluctance Motor DrivePublication . Amaral, Tito G.; Pires, Vitor; Foito, Daniel José Medronho; Cordeiro, Armando; Rocha, José Inácio Pinto Rosado; Pires, A. J.; Martins, J. F.This paper addresses the fault detection and diagnosis of a fault in the switches of the Switched Reluctance Machine (SRM) power electronic converter. Due to the advantages of using multilevel converters with these machines, a fault detection and diagnosis algorithm is proposed for this converter. The topology under consideration is the asymmetric Neutral Point Clamped (ANPC), and the algorithm was developed to detect open and short circuit faults. The proposed algorithm is based on an approach that discriminates eccentricity of the images formed by the converter voltages. This discrimination is realized through the development of normalized indexes based on the entropy theory. Besides the different fault type the algorithm is also able to detect the transistor under fault. The possibility to implement the proposed approach will be verified through simulation tests.
- A DC-DC Converter with Capability to Support the Voltage Balance of DC Bipolar MicrogridsPublication . Pires, Vítor; Foito, Daniel José Medronho; Cordeiro, Armando; Silva, J. FernandoBipolar DC microgrids are now starting to become an interesting solution for power distribution. Although presenting several advantages over DC unipolar microgrids, bipolar DC has the intrinsic problem of voltage unbalance that may appear depending on the converter topology and load sharing. Therefore, this paper presents a new DC-DC converter topology that can be used with renewable energy sources and has the capability to simultaneously ensure the bipolar microgrid voltage balance. The operation of the proposed topology together with its characteristics is described. A theoretical study of this converter will also be presented, complemented by a set of results from computer simulations. To support these simulations, results from a laboratory prototype will also be displayed. The voltage balance capability of the converter will be checked experimentally.
- A SRM for a PV Powered Water Pumping System Based on a Multilevel Converter and DC/DC Dual Output ConverterPublication . Foito, Daniel José Medronho; Cordeiro, Armando; Chaves, Miguel; Martins, J. F.This paper focuses on a proposal for a system based on a photovoltaic (PV) supply for a powered water pumping. The system consists in a switched reluctance machine (SRM) controlled by a multilevel converter and fed by PV panels associated to a DC/DC converter. The multilevel power converter proposed to control the SRM was designed to minimize the switches and to support the balance of the two input capacitors. The DC/DC converter consists in a hybrid solution that merges a Buck- Boost converter with a Sepic converter. They use a topology solution in which the input current presents a reduced ripple and only requires one switch. This DC/DC converter is also characterized by a dual output to adapt to the multilevel converter. The control system and a maximum power point tracking (MPPT) algorithm are also presented. The operation of this system will be verified by tests that are done by computer simulations.
- Quaternion-based AHRS with MEMS Motion Sensor for Biomedical ApplicationsPublication . A. Antunes, R.; Palma, Luís BritoThis work presents relevant theoretical and practical aspects towards the design of a quaternion-based real-time Attitude and Heading Reference System (AHRS). The motion sensor used in this work is the TDK InvenSense MPU-9250 9-degree (gyro + accelerometer + compass) Microelectromechan ical system. Results show that the AHRS developed device is “gimbal lock” immune, given that the 3D rotations are per formed in quaternions. The tiny electronic device allows real-time transmission of the 3D orientation and can be used as an AHRS solution for medical, sports science, rehabilitation and assistive technology. The contribution of this paper is a theoretical methodology and a practical implementation of an AHRS device for Biomedical applications.
- A Skewness Based Method for Diagnosis in Quasi-Z T-Type Grid-Connected ConvertersPublication . Amaral, Tito; Cordeiro, ArmandoOne of the very interesting converters for transformerless grid-connected PV systems is the multilevel quasi-Z T-Type inverter. Besides their multilevel operation, it presents voltage Boost capability and robustness to instantaneous switching between power semiconductors of the same leg and capability to work in fault tolerant condition. However, to ensure this capability, it is essential to ensure a fast and correct diagnosis of the component under fault. Thus, this paper proposes a new method for the detection of an open switch fault. The proposed approach uses the inverter AC line currents that will be analyzed by a Skewness based method. The method has the capability to distinguish the switch under fault. Besides that, it presents robustness to interferences such as noise, as well is insensible to variations of the injected power into the grid. Several simulation and experimental results will be presented in order to verify the capability of the proposed method.
- A Water Pumping Photovoltaic Powered System Based on a Merged DC-DC Sepic-Cuk ConverterPublication . Cordeiro, Armando; Foito, Daniel José MedronhoThis 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 the integration of a traditional Sepic and Cuk converters but requires only a single power semiconductor switch. It is characterized by an extension of the voltage static gain when compared with the classical boost topology and by a reduced voltage stress across the power switch and diodes. The system will be implemented through a classical MPPT algorithm that will control the proposed DC-DC converter. Several simulation and experimental results are also presented in order to confirm the characteristics of the proposed power converter and global water pumping systems.
- A Grid-Connected PV System Based on a Multilevel Cascaded Inverter with a Single and Three-Phase Two-Level InvertersPublication . Pires, Vítor; Monteiro, Joaquim; Silva, J. F.In this work a new multilevel cascaded inverter (MCI) based grid connected photovoltaic system is presented. The proposed MCI is based on a classic three-phase bridge inverter, where is connected the PV generator and three single-phase inverters. The asymmetry between the amplitude of the three phase bridge inverter DC source and the single phase inverter capacitor allows maximize the output levels voltage. In order to control this three-phase MCI a SPWM is used. The algorithm of this modulator will also be used to ensure the DC voltage balancing of the capacitors connected to the inverter. For this control strategy a sliding mode and PI linear controllers were also designed to obtain the modulator parameters. Simulation results are presented in order to confirm the proposed topology and the control adopted.
- Modelo da característica magnética do gerador eléctrico de relutância comutado aplicado a conversores de energia eólicaPublication . Lobato, Pedro; Rafael, Silviano; Pires, A. J.