An evaluation was made on a seasonal basis of the effect of the marine macroalga culture Gracilar... more An evaluation was made on a seasonal basis of the effect of the marine macroalga culture Gracilaria chilensis on concentrations of some soluble and particulate wastes emitted during tank cultures of a fish Isacia conteptionis, an oyster Crassostrea gigas, and a sea urchin Loxechinus albus species. The animals were each cultured in separate tanks, and effluent from each was directed through separate tanks, which contained dense cultures of the Gracilaria chilensis. Inflow-outflow monitoring was conducted for the presence of nitrate, nitrite, ammonium, and phosphate. Also evaluated were particulate nitrogen and phosphate. The most significant wastes were ammonium from the fish culture and nitrate from the oyster culture. These were completely removed from the water, with minor exceptions, by the alga during all seasons of the year. Lesser amounts of soluble phosphate and nitrite, arising from the fish cultures, were also removed. Of the particulate matter, only nitrogen was in evidence from the fish cultures in the summer. It was concluded that Gracilaria chilensis culture was highly efficient at biofiltration of the soluble nutrients tested but had little effect on particulate emissions. The best growth of Gracilaria chilensis occurred in the ammonium-rich effluent from the fish culture.
Metallized polypropylene film capacitors (MPPF) are a very interesting alternative to electrolyti... more Metallized polypropylene film capacitors (MPPF) are a very interesting alternative to electrolytic capacitors, because they can withstand much higher levels of surge voltage, very high RMS currents, and offer longer lifetimes. This paper analyses the lifetime of MPPF capacitors present in the DC link of a single-phase regenerative induction motor (IM) drive. The system under analysis contains a single-phase active
This paper proposes a first diagnostic technique for the detection and location of open-circuit f... more This paper proposes a first diagnostic technique for the detection and location of open-circuit faults in the power switches of matrix converter drives. The proposed method relies on the continuous monitoring of the amplitude of the three output error voltages and works in a two-stage approach. In a first stage, if an open-circuit fault arises in the power converter, the
Abstract The monitoring of power converters is critical for obtaining systems with self-diagnosti... more Abstract The monitoring of power converters is critical for obtaining systems with self-diagnostic capabilities and fault-tolerant features. This paper presents an analytical work concerning the operation of matrix converters (MCs) under the presence of open-circuit ...
This paper is devoted to the diagnosis of rotor faults in closed-loop induction motor drives. Dif... more This paper is devoted to the diagnosis of rotor faults in closed-loop induction motor drives. Different control strategies are studied, namely the direct torque control and the indirect rotor field oriented control. A detailed analysis of different motor/controller variables enlightens about the behavior of these systems under the presence of rotor faults. Numerous simulation results as well as experimental tests
The subject of on-line detection of rotor cage faults in three-phase induction motors is discusse... more The subject of on-line detection of rotor cage faults in three-phase induction motors is discussed, and a noninvasive approach, based on computer-aided monitoring of the stator current Park's vector, is introduced, Both simulation and laboratory test results demonstrate the effectiveness of the proposed technique, for detecting broken rotor bars or end-rings in operating three-phase induction machines. On-site tests conducted in a power plant, using the diagnostic instrumentation system developed, are also reported
This paper deals with the use of the total instantaneous power spectral analysis for diagnosing t... more This paper deals with the use of the total instantaneous power spectral analysis for diagnosing the occurrence of rotor cage faults in operating three-phase induction motors. The theoretical principles directly related to the application of this diagnostic technique are described, emphasizing the role of parameters such as the magnetizing current, motor-load inertia, motor rating and load level, in the diagnostic process. Both simulation and laboratory tests results demonstrate the effectiveness of the total instantaneous power spectral analysis for diagnosing the presence of rotor cage faults. The development of a severity factor, in order to evaluate the extension of the fault, is reported, and it is shown how this severity factor is almost independent of parameters such as the magnetizing current, motor rating and motor-load inertia
This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occ... more This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in the laboratory, corroborate that these faults can be detected, in the EPVA signature, by the identification of a spectral component at twice the fundamental supply frequency. On-site tests, conducted in a power generation plant and in a cement mill, demonstrate the effectiveness of the EPVA in the detection of stator circuit faults in large industrial motors, rated up to 5 MW
This paper presents the development of a simulation model of a matrix converter drive with the ai... more This paper presents the development of a simulation model of a matrix converter drive with the aim to diagnose faults in the converter. Using a model developed in Simulink environment, simulation results were obtained demonstrating that the occurrence of an open-circuit fault in one of the power switches of the matrix converter affects heavily the operation of the motor, leading to appearance of high overvoltages at the motor terminals and to significant torque oscillations.
Page 1. Diagnosis of Stator, Rotor and Airgap Eccentricity Faults in Three-Phase Induction Motors... more Page 1. Diagnosis of Stator, Rotor and Airgap Eccentricity Faults in Three-Phase Induction Motors Based on the Multiple Reference Frames Theory SMA Cruz and AJM Cardoso Department of Electrical and Computer Engineering ...
This paper exploits the use of the multiple reference frames theory for the diagnosis of stator f... more This paper exploits the use of the multiple reference frames theory for the diagnosis of stator faults in three-phase induction motors. A simplified mathematical model in d-q-0 axes, able to simulate the behavior of the motor in the presence of stator faults, allowed the development of some analytical relations between the d-q-0 current components in different reference frames. The use of the stationary reference frame, clockwise and counterclockwise synchronous reference frames, allows the extraction and manipulation of the information contained in the three motor supply currents in a way that the effects introduced by the fault are isolated and measured. A severity factor is defined, and simulation and experimental results demonstrate its high independence in relation to the working conditions of the motor such as the load level and unbalances in the voltage supply system.
This paper presents a new method to diagnose open-circuit faults in matrix converters. The propos... more This paper presents a new method to diagnose open-circuit faults in matrix converters. The proposed method consists in the measurement and estimation, simultaneously, of the three output phase voltages of the matrix converter. Afterwards, three error voltage signals are generated, which will be subsequently modulated using the control signals of each bidirectional switch of the converter. The nine modulated error
An evaluation was made on a seasonal basis of the effect of the marine macroalga culture Gracilar... more An evaluation was made on a seasonal basis of the effect of the marine macroalga culture Gracilaria chilensis on concentrations of some soluble and particulate wastes emitted during tank cultures of a fish Isacia conteptionis, an oyster Crassostrea gigas, and a sea urchin Loxechinus albus species. The animals were each cultured in separate tanks, and effluent from each was directed through separate tanks, which contained dense cultures of the Gracilaria chilensis. Inflow-outflow monitoring was conducted for the presence of nitrate, nitrite, ammonium, and phosphate. Also evaluated were particulate nitrogen and phosphate. The most significant wastes were ammonium from the fish culture and nitrate from the oyster culture. These were completely removed from the water, with minor exceptions, by the alga during all seasons of the year. Lesser amounts of soluble phosphate and nitrite, arising from the fish cultures, were also removed. Of the particulate matter, only nitrogen was in evidence from the fish cultures in the summer. It was concluded that Gracilaria chilensis culture was highly efficient at biofiltration of the soluble nutrients tested but had little effect on particulate emissions. The best growth of Gracilaria chilensis occurred in the ammonium-rich effluent from the fish culture.
Metallized polypropylene film capacitors (MPPF) are a very interesting alternative to electrolyti... more Metallized polypropylene film capacitors (MPPF) are a very interesting alternative to electrolytic capacitors, because they can withstand much higher levels of surge voltage, very high RMS currents, and offer longer lifetimes. This paper analyses the lifetime of MPPF capacitors present in the DC link of a single-phase regenerative induction motor (IM) drive. The system under analysis contains a single-phase active
This paper proposes a first diagnostic technique for the detection and location of open-circuit f... more This paper proposes a first diagnostic technique for the detection and location of open-circuit faults in the power switches of matrix converter drives. The proposed method relies on the continuous monitoring of the amplitude of the three output error voltages and works in a two-stage approach. In a first stage, if an open-circuit fault arises in the power converter, the
Abstract The monitoring of power converters is critical for obtaining systems with self-diagnosti... more Abstract The monitoring of power converters is critical for obtaining systems with self-diagnostic capabilities and fault-tolerant features. This paper presents an analytical work concerning the operation of matrix converters (MCs) under the presence of open-circuit ...
This paper is devoted to the diagnosis of rotor faults in closed-loop induction motor drives. Dif... more This paper is devoted to the diagnosis of rotor faults in closed-loop induction motor drives. Different control strategies are studied, namely the direct torque control and the indirect rotor field oriented control. A detailed analysis of different motor/controller variables enlightens about the behavior of these systems under the presence of rotor faults. Numerous simulation results as well as experimental tests
The subject of on-line detection of rotor cage faults in three-phase induction motors is discusse... more The subject of on-line detection of rotor cage faults in three-phase induction motors is discussed, and a noninvasive approach, based on computer-aided monitoring of the stator current Park's vector, is introduced, Both simulation and laboratory test results demonstrate the effectiveness of the proposed technique, for detecting broken rotor bars or end-rings in operating three-phase induction machines. On-site tests conducted in a power plant, using the diagnostic instrumentation system developed, are also reported
This paper deals with the use of the total instantaneous power spectral analysis for diagnosing t... more This paper deals with the use of the total instantaneous power spectral analysis for diagnosing the occurrence of rotor cage faults in operating three-phase induction motors. The theoretical principles directly related to the application of this diagnostic technique are described, emphasizing the role of parameters such as the magnetizing current, motor-load inertia, motor rating and load level, in the diagnostic process. Both simulation and laboratory tests results demonstrate the effectiveness of the total instantaneous power spectral analysis for diagnosing the presence of rotor cage faults. The development of a severity factor, in order to evaluate the extension of the fault, is reported, and it is shown how this severity factor is almost independent of parameters such as the magnetizing current, motor rating and motor-load inertia
This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occ... more This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in the laboratory, corroborate that these faults can be detected, in the EPVA signature, by the identification of a spectral component at twice the fundamental supply frequency. On-site tests, conducted in a power generation plant and in a cement mill, demonstrate the effectiveness of the EPVA in the detection of stator circuit faults in large industrial motors, rated up to 5 MW
This paper presents the development of a simulation model of a matrix converter drive with the ai... more This paper presents the development of a simulation model of a matrix converter drive with the aim to diagnose faults in the converter. Using a model developed in Simulink environment, simulation results were obtained demonstrating that the occurrence of an open-circuit fault in one of the power switches of the matrix converter affects heavily the operation of the motor, leading to appearance of high overvoltages at the motor terminals and to significant torque oscillations.
Page 1. Diagnosis of Stator, Rotor and Airgap Eccentricity Faults in Three-Phase Induction Motors... more Page 1. Diagnosis of Stator, Rotor and Airgap Eccentricity Faults in Three-Phase Induction Motors Based on the Multiple Reference Frames Theory SMA Cruz and AJM Cardoso Department of Electrical and Computer Engineering ...
This paper exploits the use of the multiple reference frames theory for the diagnosis of stator f... more This paper exploits the use of the multiple reference frames theory for the diagnosis of stator faults in three-phase induction motors. A simplified mathematical model in d-q-0 axes, able to simulate the behavior of the motor in the presence of stator faults, allowed the development of some analytical relations between the d-q-0 current components in different reference frames. The use of the stationary reference frame, clockwise and counterclockwise synchronous reference frames, allows the extraction and manipulation of the information contained in the three motor supply currents in a way that the effects introduced by the fault are isolated and measured. A severity factor is defined, and simulation and experimental results demonstrate its high independence in relation to the working conditions of the motor such as the load level and unbalances in the voltage supply system.
This paper presents a new method to diagnose open-circuit faults in matrix converters. The propos... more This paper presents a new method to diagnose open-circuit faults in matrix converters. The proposed method consists in the measurement and estimation, simultaneously, of the three output phase voltages of the matrix converter. Afterwards, three error voltage signals are generated, which will be subsequently modulated using the control signals of each bidirectional switch of the converter. The nine modulated error
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