EPE Association: EPE 2015 - LS5c: Electrical machines

EPE 2015 - LS5c: Electrical machines
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 04: Electrical Machines and Drive Systems > EPE 2015 - LS5c: Electrical machines

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   Improvement of the Ground-Fault Detection in Field Windings of Synchronous Machines with Static Excitation based on Third-Harmonic Voltage Phase-Angle Compariso
By Francisco BLANQUEZ [View]
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Abstract: This paper presents the theoretical approach and experimental tests of a new algorithm for detecting ground faults in rotor windings of synchronous generators with static excitation. This location method requires the installation of a grounding resistance in the secondary winding of the excitation transformer. First, the third-harmonic reference voltage is obtained by the voltage measurements in the excitation system. Then, the third-harmonic voltage at the grounding resistor is compared to the reference voltage. The ground fault is detected when the phase angle between those voltages is under the trip setting value. This new algorithm has been tested in a 5 kVA Synchronous generator with satisfactory results.

   Modeling and control of a stand alone Cascaded Doubly Fed Induction Generator supplying an isolated load
By Maria EL ACHKAR [View]
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Abstract: The modeling and control of a variable speed cascaded doubly fed induction generator feeding an isolatedgrid in aircraft application is presented. Despite the complexity of the generator an efficient controllercan be elaborated based on the theory of a unified reference frame vector representation. An indirectdecoupled vector control of terminal voltage is implemented using field orientation techniques. Thecontroller insures good tracking of voltage magnitude and frequency regardless load and speed variations.

   Modeling and harmonic analysis of a permanent magnet synchronous machine with turn-to-turn fault
By Joachim HÃ„RSJÃ– [View]
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Abstract: This paper presents analytical models of a permanent magnet synchronous machine with a turn-to-turn fault, both in the stationary and in the synchronously-rotating reference frame. The models are used to investigate how a turn-to-turn fault impacts the harmonic content of the machine. These models can thus be a powerful tool in order to identify a specific behavior caused by the fault, which can be further utilized for fault detection and/or condition monitoring applications. It is shown that, due to the fault condition, the amplitude of the harmonics in the back-EMF changes compared with the pre-fault conditions; the amplitude change is dependent on the number or short-circuited turns in the winding. If a reduced number of short-circuited turns are considered (as typically the case at the beginning of the fault and as considered in this paper), the harmonic amplitude change is comparatively small and therefore difficult to detect. It is shown that a more powerful indication of the turn-to-turn fault is to monitor the current harmonic content in the rotating reference frame, where new harmonics are introduced due to the unbalance caused by the turn-to-turn fault.

   Modeling and Parameter Identification of Multiphase Permanent Magnet Synchronous Motors Including Saturation Effects
By Torben JONSKY [View]
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Abstract: An extended modeling of a multiphase machine is presented in this paper, under consideration of inductance harmonics. It is shown that an independent control of the phase currents in a multiphase machine can contribute to a higher efficiency by generating constant torque from harmonics in the flux-linkage due to injecting current harmonics into the stator windings.The extended modeling requires the knowledge of differential and absolute inductances and the permanent-magnet rotor flux. Therefore a novel measurement method is demonstrated, which is capable of identifying the inductances and flux-linkages for an arbitrary motor. The measurement method is compared with simulation results from a novel simulation method for a three-phase machine, checked for plausibility and is extended to a five-phase machine.The extended modeling and the knowledge of inductances with respect to the operating point and rotor position enables the design of an improved control system. Simulations of a five-phase motor without a star-point connection show that the torque ripple can be improved significantly, even if measuring errors and noise are considered. The performance and especially the dynamic of the drive system can be increased by adjusting the static gain of the current controller as a function of the operating point.

EPE 2015 - LS5c: Electrical machines
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2015 ECCE Europe - Conference > EPE 2015 - Topic 04: Electrical Machines and Drive Systems > EPE 2015 - LS5c: Electrical machines
	[return to parent folder]

	Improvement of the Ground-Fault Detection in Field Windings of Synchronous Machines with Static Excitation based on Third-Harmonic Voltage Phase-Angle Compariso By Francisco BLANQUEZ	[View] [Download]
Abstract: This paper presents the theoretical approach and experimental tests of a new algorithm for detecting ground faults in rotor windings of synchronous generators with static excitation. This location method requires the installation of a grounding resistance in the secondary winding of the excitation transformer. First, the third-harmonic reference voltage is obtained by the voltage measurements in the excitation system. Then, the third-harmonic voltage at the grounding resistor is compared to the reference voltage. The ground fault is detected when the phase angle between those voltages is under the trip setting value. This new algorithm has been tested in a 5 kVA Synchronous generator with satisfactory results.

	Modeling and control of a stand alone Cascaded Doubly Fed Induction Generator supplying an isolated load By Maria EL ACHKAR	[View] [Download]
Abstract: The modeling and control of a variable speed cascaded doubly fed induction generator feeding an isolatedgrid in aircraft application is presented. Despite the complexity of the generator an efficient controllercan be elaborated based on the theory of a unified reference frame vector representation. An indirectdecoupled vector control of terminal voltage is implemented using field orientation techniques. Thecontroller insures good tracking of voltage magnitude and frequency regardless load and speed variations.

	Modeling and harmonic analysis of a permanent magnet synchronous machine with turn-to-turn fault By Joachim HÃ„RSJÃ–	[View] [Download]
Abstract: This paper presents analytical models of a permanent magnet synchronous machine with a turn-to-turn fault, both in the stationary and in the synchronously-rotating reference frame. The models are used to investigate how a turn-to-turn fault impacts the harmonic content of the machine. These models can thus be a powerful tool in order to identify a specific behavior caused by the fault, which can be further utilized for fault detection and/or condition monitoring applications. It is shown that, due to the fault condition, the amplitude of the harmonics in the back-EMF changes compared with the pre-fault conditions; the amplitude change is dependent on the number or short-circuited turns in the winding. If a reduced number of short-circuited turns are considered (as typically the case at the beginning of the fault and as considered in this paper), the harmonic amplitude change is comparatively small and therefore difficult to detect. It is shown that a more powerful indication of the turn-to-turn fault is to monitor the current harmonic content in the rotating reference frame, where new harmonics are introduced due to the unbalance caused by the turn-to-turn fault.

	Modeling and Parameter Identification of Multiphase Permanent Magnet Synchronous Motors Including Saturation Effects By Torben JONSKY	[View] [Download]
Abstract: An extended modeling of a multiphase machine is presented in this paper, under consideration of inductance harmonics. It is shown that an independent control of the phase currents in a multiphase machine can contribute to a higher efficiency by generating constant torque from harmonics in the flux-linkage due to injecting current harmonics into the stator windings.The extended modeling requires the knowledge of differential and absolute inductances and the permanent-magnet rotor flux. Therefore a novel measurement method is demonstrated, which is capable of identifying the inductances and flux-linkages for an arbitrary motor. The measurement method is compared with simulation results from a novel simulation method for a three-phase machine, checked for plausibility and is extended to a five-phase machine.The extended modeling and the knowledge of inductances with respect to the operating point and rotor position enables the design of an improved control system. Simulations of a five-phase motor without a star-point connection show that the torque ripple can be improved significantly, even if measuring errors and noise are considered. The performance and especially the dynamic of the drive system can be increased by adjusting the static gain of the current controller as a function of the operating point.