EPE Association: EPE 2020 - LS2e: Multiphase Drives

EPE 2020 - LS2e: Multiphase Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 04: Electrical Machines and Drive Systems > EPE 2020 - LS2e: Multiphase Drives

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   Analytical computation of normal and fault-tolerant active short circuit operation of anisotropic synchronous double star machines
By Michael GLEISSNER [View]
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Abstract: The analytical computation of anisotropic synchronous machines enables a fast and simple assessment of the speed-torque operation range depending on the machine parameters. A known analytical approach considering stator resistance and mutual inductance for three-phase machines is extended to double starmachines for normal and fault-tolerant mode. The decisive parameters for a successful degraded operation with an active short-circuit of one of the two winding systems are evaluated, which reduces the number of disconnection elements for short-on failures of switches and windings.

   Comparative assessment of PWM methods for control of asymmetric Six-Phase Permanent Magnet Synchronous Machine
By Rahul KANCHAN [View]
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Abstract: In the most common industrial adaptation of electric drives for asymmetric six-phase machines, two independent three-phase converter units are configured to supply two three-phase winding sets. In principle, the converter units may use their own internal clock, acting independently on the two sets of windings with both the voltage pulse-width modulation and the sampling of phase currents. In the case, the machine is controlled with a vector space decomposition approach, this may cause some synchronization issues with voltage references and current sampling.In this paper, an asymmetric six-phase permanent-magnet machine is controlled with a vector space decomposition architecture has been controlled with individual current controllers in each harmonic plane. The output voltage references from the current controllers is fed to pulse-width modulators. The modulators are selected among the most promising methods for two-level converter-fed six-phase machines from the literature. A comparative analysis is performed through simulation studies, with the objective of comparing the performance of various modulators considering synchronization of voltage reference signals and phase current sampling.

   Comparison of optimized motor-inverter systems using a Stacked Polyphase Bridge Converter combined with a 3-, 6-, 9-, or 12-phase PMSM
By Thilo BRINGEZU [View]
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Abstract: Stacked Polyphase Bridge Converters (SPB-C) are well suited for integrated motor drives, i.e. for systems that combine an electric motor with its supplying power electronic converter in one compact unit. A SPB-C requires a motor with multiple 3-phase winding systems. In the literature, the SPB-C is typically combined with motors whose winding systems are phase-aligned. This type of winding is magnetically equivalent to a 3-phase winding (with parallel branches). In this paper, the SPB-C with either 2, 3, or 4 modules is combined with a motor that has non-phase-aligned winding systems what results in a 6-, a 9-, or a 12-phase system, respectively. These multiphase systems are compared to 3-phase systems with the same number of modules with regard to efficiency, power density, and the possible degree of modularity and the benefits of the multiphase systems are evaluated.

   Optimal torque/speed characteristics of a Five-Phase Synchronous Machine under Peak or RMS current control strategies
By Tiago José DOS SANTOS MORAES [View]
[Download]

Abstract: Torque density is usually improved by injecting the third current harmonic for five-phase permanent magnet synchronous machine (PMSM). It increases the degrees of freedom of a multiphase drive. However, it also separates the current limitations of the motor and the transistors, respectively related to the RMS and peak values of the currents. These two constraints are represented by Maximum Torque Per Ampere (MTPA) strategy and Maximum Torque Per Peak Current (MTPPC) strategy. In this paper, these two strategies are studied and analyzed in order to optimize the generated torque with injection of the third current harmonic. Torque improvement principle and the optimizing algorithm considering two constraints are illustrated. Then, the analytical results of these two strategies are compared and discussed. It is shown that injecting the third current harmonic can improve the torque especially at flux-weakening region. Besides, compared with MTPA, MTPPC could produce higher torque for the same inverter current limit.

EPE 2020 - LS2e: Multiphase Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 04: Electrical Machines and Drive Systems > EPE 2020 - LS2e: Multiphase Drives
	[return to parent folder]

	Analytical computation of normal and fault-tolerant active short circuit operation of anisotropic synchronous double star machines By Michael GLEISSNER	[View] [Download]
Abstract: The analytical computation of anisotropic synchronous machines enables a fast and simple assessment of the speed-torque operation range depending on the machine parameters. A known analytical approach considering stator resistance and mutual inductance for three-phase machines is extended to double starmachines for normal and fault-tolerant mode. The decisive parameters for a successful degraded operation with an active short-circuit of one of the two winding systems are evaluated, which reduces the number of disconnection elements for short-on failures of switches and windings.

	Comparative assessment of PWM methods for control of asymmetric Six-Phase Permanent Magnet Synchronous Machine By Rahul KANCHAN	[View] [Download]
Abstract: In the most common industrial adaptation of electric drives for asymmetric six-phase machines, two independent three-phase converter units are configured to supply two three-phase winding sets. In principle, the converter units may use their own internal clock, acting independently on the two sets of windings with both the voltage pulse-width modulation and the sampling of phase currents. In the case, the machine is controlled with a vector space decomposition approach, this may cause some synchronization issues with voltage references and current sampling.In this paper, an asymmetric six-phase permanent-magnet machine is controlled with a vector space decomposition architecture has been controlled with individual current controllers in each harmonic plane. The output voltage references from the current controllers is fed to pulse-width modulators. The modulators are selected among the most promising methods for two-level converter-fed six-phase machines from the literature. A comparative analysis is performed through simulation studies, with the objective of comparing the performance of various modulators considering synchronization of voltage reference signals and phase current sampling.

	Comparison of optimized motor-inverter systems using a Stacked Polyphase Bridge Converter combined with a 3-, 6-, 9-, or 12-phase PMSM By Thilo BRINGEZU	[View] [Download]
Abstract: Stacked Polyphase Bridge Converters (SPB-C) are well suited for integrated motor drives, i.e. for systems that combine an electric motor with its supplying power electronic converter in one compact unit. A SPB-C requires a motor with multiple 3-phase winding systems. In the literature, the SPB-C is typically combined with motors whose winding systems are phase-aligned. This type of winding is magnetically equivalent to a 3-phase winding (with parallel branches). In this paper, the SPB-C with either 2, 3, or 4 modules is combined with a motor that has non-phase-aligned winding systems what results in a 6-, a 9-, or a 12-phase system, respectively. These multiphase systems are compared to 3-phase systems with the same number of modules with regard to efficiency, power density, and the possible degree of modularity and the benefits of the multiphase systems are evaluated.

	Optimal torque/speed characteristics of a Five-Phase Synchronous Machine under Peak or RMS current control strategies By Tiago José DOS SANTOS MORAES	[View] [Download]
Abstract: Torque density is usually improved by injecting the third current harmonic for five-phase permanent magnet synchronous machine (PMSM). It increases the degrees of freedom of a multiphase drive. However, it also separates the current limitations of the motor and the transistors, respectively related to the RMS and peak values of the currents. These two constraints are represented by Maximum Torque Per Ampere (MTPA) strategy and Maximum Torque Per Peak Current (MTPPC) strategy. In this paper, these two strategies are studied and analyzed in order to optimize the generated torque with injection of the third current harmonic. Torque improvement principle and the optimizing algorithm considering two constraints are illustrated. Then, the analytical results of these two strategies are compared and discussed. It is shown that injecting the third current harmonic can improve the torque especially at flux-weakening region. Besides, compared with MTPA, MTPPC could produce higher torque for the same inverter current limit.