Showing papers by "V. Fernao Pires published in 2013"
TL;DR: In this article, a new motor square current signature analysis (MSCSA) fault diagnosis methodology is presented, which is based on three main steps: first, the induction motor current is measured; secondly, the square of the current is computed; and finally a frequency analysis of the square current is performed.
71 citations
05 Jun 2013
TL;DR: In this paper, a system controller for a three-phase grid-connected inverter for photovoltaic applications is presented, where active and reactive currents are both controlled in order to realize active power supply and reactive power compensation.
Abstract: A system controller for a three-phase grid-connected inverter for photovoltaic applications is presented. The active and reactive currents will both be controlled in order to realize active power supply and reactive power compensation. The three-phase inverter will be controlled by a fast and robust sliding mode controller. The active and reactive current references will be calculated in order to maximize the electrical energy produced by PV arrays and at the same time as a reactive power compensator. For the calculation of these references the maximum apparent power of the three-phase inverter is also considered. When the PV system is not working at full power the three-phase inverter can also be working as reactive power compensator. The grid injected reactive power is limited by the maximum apparent power of the inverter. This allows integrating this system into a smart-grid. Numerical simulations obtained in the Simulink environment are presented in order to validate the proposed system.
15 citations
20 Oct 2013
TL;DR: The design and implementation of a data acquisition system for photovoltaic systems is presented, characterized by a low cost board based on a microcontroller that can be used for reading, storing and analyzing information from several photovolar systems.
Abstract: Testing PV modules are one of the important procedures to ensure the conformity with the standards and quality of this equipment's. To implement some of the PV modules tests a data acquisition system is required. This paper presents the design and implementation of a data acquisition system for photovoltaic systems. The developed system is characterized by a low cost board based on a microcontroller. The description of the hardware as well an application to test its performance is presented. The developed system can be used for reading, storing and analyzing information from several photovoltaic systems. Experimental tests are presented to confirm the characteristics of the developed data acquisition board.
12 citations
01 Dec 2013
TL;DR: The electric differential was implemented assuring that, in straight right trajectory, the two wheels drives roll exactly at same velocity and, in curve, the difference between the two velocities assure a vehicle trajectory.
Abstract: This paper presents an electric vehicle (EV) with two independent rear wheel drives and with an electric differential system. A model of the vehicle dynamic model is presented. The electric differential was implemented assuring that, in straight right trajectory, the two wheels drives roll exactly at same velocity and, in curve, the difference between the two velocities assure a vehicle trajectory. A speed and torque observer for DC motor was also proposed and simulated. Analysis and simulation results of the proposed system are presented.
7 citations
01 Jan 2013
TL;DR: In this paper, a three-phase nine switch inverter for a grid-connected photovoltaic (PV) system is presented, where a sliding mode controller associated to vectorial modulator is used to control this power converter.
Abstract: In this paper it is presented a three-phase nine switch inverter for a grid-connected photovoltaic (PV) system. The structure of this power converter is based on the classical three-phase voltage source inverter. However, it requires three extra bi-directional switches and presents a multilevel characteristic. Thus, reducing switching frequency and/or inverter ac voltages with reduced THD are obtained. To control this power converter a sliding mode controller associated to vectorial modulator is used. The performance of the proposed PV system is verified by time-domain simulation studies.
6 citations
15 Apr 2013
TL;DR: An on-line system for detection and diagnosis of electrical faults in induction machines based on computer-aided monitoring of the supply currents and Principal Component Analysis (PCA) is presented.
Abstract: Nowadays in industry there many processes where human intervention is replaced by electrical machines, especially induction machines due to his robustness and performance. Although, induction machines are a high reliable device, they are also susceptible to faults. Therefore, the study of induction machine state is essential to reduce human and financial costs. It is presented in this paper an on-line system for detection and diagnosis of electrical faults in induction machines based on computer-aided monitoring of the supply currents. The main objective is to detect and identify the presence of broken rotor bars and stator short-circuits in the induction motor. The presence of faults in the machine causes different disturbances in the supply currents. Through a stationary reference frame, such as αβ-vector transform it is possible to extract and manipulate the results obtained from the supply currents using Principal Component Analysis (PCA).
6 citations