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ABSTRACT: One of the main features of a switched reluctance motor is its fault tolerance capability. However performance deterioration is clearly evident when one phase is removed. This paper presents a fault tolerant power converter, applied to a four phases switched reluctance motor. Some possible additional connections on the commonly used asymmetric bridge converter are introduced to secure the operation of all phases even after a fault occurrence responsible for a power converter switch disconnection. Simulated results indicate that normal operation can nearly be restored at low speed operation and SRM performance behavior is clearly improved at high speed operation. Dynamic operating conditions, under normal and faulty operations with and without the use of the fault tolerant power converter, are analyzed. A high speed operating example, for all the referred operating modes and considering the same speed and load conditions, is presented. Time-domain waveforms of the phase currents, power converter supply current, electromagnetic torque and mechanical speed are presented as well as the spectral analysis of the power converter supply current and electromagnetic torque.
Electrical Machines, 2008. ICEM 2008. 18th International Conference on; 10/2008
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ABSTRACT: In this paper a new fault detection technique based on the instantaneous power factor signature analysis is proposed for the diagnosis of rotor cage faults in three-phase induction motors. A mathematical model based on the Winding Function Approach was used for the simulation of this type of fault and experimental tests were carried out on an induction motor with several faulty rotors. Both simulation and experimental results are presented to illustrate the effectiveness of the proposed approach. A suitable fault severity factor is also proposed as an indicator of the machine condition.
Power Electronics, Electrical Drives, Automation and Motion, 2008. SPEEDAM 2008. International Symposium on; 07/2008
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ABSTRACT: This paper reports on the study of the load-commutated inverter drive operating with an open-switch fault in the line-side converters. To improve this faulty operation, some strategies are presented in order to decrease the harmonic content of currents and the pulsating torque of the motor. To validate the proposed strategies, experimental results are presented.
IEEE Transactions on Industrial Electronics 06/2008; · 5.16 Impact Factor
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ABSTRACT: This paper presents the thermal behavior of a three-phase induction motor under direct torque control, when supplied by a three-phase voltage source inverter with fault tolerant capabilities. For this purpose, a fault tolerant operating strategy based on the connection of the faulty inverter leg to the dc link middle point was considered. The motor thermal profile is obtained through the use of nine thermocouples positioned in both stator and rotor circuits. The experimental results obtained under fault compensated operation show that, as far as the motor thermal characteristics are concerned, it is not necessary to reinforce the motor insulation properties since it is already prepared for such an operation.
IEEE Transactions on Power Electronics 06/2008; · 4.65 Impact Factor
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ABSTRACT: The aim of this paper is to introduce a new fault detection technique based on the use of the instantaneous power factor signature analysis as a tool for the diagnostics of mixed airgap eccentricity in operating three-phase squirrel cage induction motors. Firstly, a modelling and simulation study concerning the occurrence of airgap eccentricity in three-phase induction motors is presented. For that purpose, the winding function approach is considered. Then, both simulation and experimental results are presented to illustrate the effectiveness of this new proposed approach.
Power Electronics, Machines and Drives, 2008. PEMD 2008. 4th IET Conference on; 05/2008
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ABSTRACT: The aim of this paper is to present a simple simulation technique based in Laplace transform, which allows the analysis of both transient and steady state response of switch mode power supplies (SMPS). Further, an experimental LCR meter is also presented in order to evaluate the capacitor equivalent circuit parameters at the converter operating frequency. Both techniques can be used at the design stage of SMPS, in order to improve the quality of the final prototype, since the effects of these parasitic elements present in electrolytic capacitors can be foreseen. Simulation, experimental and theoretical results are then presented in order to prove the applicability of the present simulation tool.
Telecommunications Energy Conference, 2007. INTELEC 2007. 29th International; 11/2007
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ABSTRACT: In this paper, a novel online technique for estimating the parameters of a DC/DC buck converter through a continuous time model is proposed. Standard least mean squares algorithm is applied among other formulations, taking into account only the non conduction state during a single switching cycle. The problem of derivative calculation of the needed voltage and current signals is solved by polynomial interpolation.
Power Electronics and Applications, 2007 European Conference on; 10/2007
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ABSTRACT: Detection of broken rotor bars has long been an important but difficult job in the detection area of motor faults. The characteristic frequency components of a faulted rotor in the stator current spectrum are very close to the power frequency component but by far less in amplitude, which brings about great difficulty for accurate detection. In this paper a new detection method based on the instantaneous phase-angle signature analysis is proposed for the diagnosis of rotor cage faults in operating three-phase induction motors. For that purpose, a mathematical model based on the winding function approach is used in order to simulate this type of fault and experimental tests are carried out on an induction motor with several faulty rotors. Simulation and experimental results are presented to show the merits of this novel approach for the detection of cage induction motor broken rotor bars.
Electric Machines & Drives Conference, 2007. IEMDC '07. IEEE International; 06/2007
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ABSTRACT: The aim of this paper is to introduce the use of the instantaneous phase-angle signature analysis as a tool for the diagnostics of mixed airgap eccentricity in operating three-phase squirrel cage induction motors. Firstly, a modelling and simulation study concerning the occurrence of airgap eccentricity in three-phase induction motors is presented. For that purpose, the Winding Function Approach is considered. Then, both simulation and experimental results are presented to illustrate the effectiveness of this new proposed approach.
Power Engineering, Energy and Electrical Drives, 2007. POWERENG 2007. International Conference on; 05/2007
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ABSTRACT: This paper presents a comparative analysis involving several fault-tolerant operating strategies, applied to three-phase induction-motor drives, that intend to compensate for inverter faults. The results presented show the advantages and the inconveniences of several fault-tolerant drive structures, under different control techniques, such as the field-oriented control and the direct torque control. Experimental results concerning the performance of the three-phase induction motor, based on the analysis of some key parameters, like induction-motor efficiency, motor power factor, and harmonic distortion of both motor line currents and phase voltages, will be presented
IEEE Transactions on Industrial Electronics 01/2007; · 5.16 Impact Factor
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ABSTRACT: This paper presents an experimental technique that allows the determination of the reactance and ESR intrinsic values of aluminum electrolytic capacitors. The equivalent circuit of an electrolytic capacitor comprises an equivalent series inductance (ESL), an equivalent series resistance (ESR) and a capacitance (C), whose values change with frequency. Therefore, the behavior of an electrolytic capacitor varies from approximately a simple capacitor for low frequencies, to a resistor at its resonance frequency, and finally to an inductor for frequencies higher than its resonance frequency. The knowledge of the resonance frequency of the electrolytic capacitors, as well as their equivalent circuit at the operating frequency becomes of paramount importance for designing purposes. The ESR is one of the most critical problems of static converters that operate near the resonance frequency of the electrolytic capacitors. An increased ESR value leads to a significant increase in the alternate component of the output voltage, requiring a constant action of the control system. To validate the proposed technique and to demonstrate its applicability some experimental and simulated results are presented
Instrumentation and Measurement Technology Conference, 2006. IMTC 2006. Proceedings of the IEEE; 05/2006
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ABSTRACT: This paper presents a laboratory method that can be used to determine the intrinsic value of the equivalent series resistance (ESR) of electrolytic capacitors. One of the most critical problems of switch mode DC-DC converter designers is the ESR, which introduces a high AC component in the output voltage. Thus, the knowledge of this value at the converter operating conditions is fundamental to predict the output response of the converter. To validate this technique some experimental and simulated results are presented
Power Electronics and Drives Systems, 2005. PEDS 2005. International Conference on; 12/2005
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ABSTRACT: This paper reports on the study of the Load Commutated Inverter drive, operating with an open-switch fault in the machine-side converters. To improve this faulty operation and increase the availability of the drive some strategies are discussed, in order to decrease the harmonic content of currents and the pulsating torque of the motor. To validate the proposed strategies, experimental results are presented.
Power Electronics, Machines and Drives, 2004. (PEMD 2004). Second International Conference on (Conf. Publ. No. 498); 05/2004
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ABSTRACT: This paper presents an analysis of the switched reluctance motor dynamic operation under power converter fault conditions. Open- and short-circuit faults in the converter power switches are considered. Normal operating results are also included, as a reference. Time-domain waveforms of the phase currents, electromagnetic torque, power converter supply current and mechanical speed are presented and discussed as well as the spectral analysis of the power converter supply current and electromagnetic torque. The paper also presents a switched reluctance motor model, used for the power converter fault analysis simulation studies.
Industrial Electronics, 2003. ISIE '03. 2003 IEEE International Symposium on; 07/2003
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ABSTRACT: This paper presents a study regarding the continuous operation performance of a faulty three-phase induction motor fed by a direct torque controlled voltage source inverter. Several remedial operating strategies are compared in order to analyze which of them better fit into a post-fault drive reconfiguration strategy. This analysis comprises input motor line current distortion and efficiency. Electromagnetic torque harmonics are also taken into account.
Electric Machines and Drives Conference, 2003. IEMDC'03. IEEE International; 07/2003
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ABSTRACT: This paper presents a study regarding the performance of a standard three-phase induction motor fed by a voltage source inverter, controlled by the most recent control techniques such as field oriented control, direct torque control and fuzzy logic space vector modulation. With this work, the authors intend to analyze which of these control techniques better fit into a remedial operating strategy, regarding the three-phase induction motor post-fault performance. Simulation results are presented.
Power Electronics, Machines and Drives, 2002. International Conference on (Conf. Publ. No. 487); 07/2002
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ABSTRACT: 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
Industry Applications Conference, 2000. Conference Record of the 2000 IEEE; 02/2000
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ABSTRACT: The subject of on-line detection and location of inter-turn short
circuits in the stator windings of three-phase induction motors is
discussed, and a noninvasive approach, based on the computer-aided
monitoring of the stator current Park's vector, is introduced.
Experimental results, obtained by using a special fault producing test
rig, demonstrate the effectiveness of the proposed technique, for
detecting inter-turn stator winding faults in operating three-phase
induction machines. On-site tests conducted in a power generation plant,
using the diagnostic instrumentation system developed, are also reported
IEEE Transactions on Energy Conversion 10/1999; · 2.27 Impact Factor
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ABSTRACT: This paper introduces a new approach, based on the average motor
supply current Park's vector monitoring, for diagnosing voltage source
inverter faults in variable speed AC drives. Both simulation and
laboratory tests results demonstrate the effectiveness of the proposed
on-line diagnostic technique
Electric Machines and Drives, 1999. International Conference IEMD '99; 06/1999
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ABSTRACT: This paper presents a noninvasive approach, based on the
computer-aided monitoring of the three-phase supply current Park's
vector, for diagnosing converter faults in variable speed DC drives.
Both simulation and laboratory tests results demonstrate the
effectiveness of the proposed technique, for detecting either
open-circuit or short-circuit faults in the converter power switches and
also for identifying which is the faulty element
Industrial Electronics, 1997. ISIE '97., Proceedings of the IEEE International Symposium on; 08/1997
