Variable-speed, sub-harmonically excited BL-WRSM avoiding unbalanced radial force

Ali, Qasim; Bukhari, Syed Sabir Hussain; Atiq, Shahid

doi:10.1007/s00202-019-00772-2

Cited by 15 publications

(21 citation statements)

References 11 publications

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“…Brushless WRSMs operate on the principle of the generation of harmonic MMF in the airgap of the machine. This sometimes results in an unbalanced radial force on the rotor of the machine 20 . The unbalanced radial force often has a negative impact on the performance of the machine and results in an unequal stress on its bearings.…”

Section: Electromagnetic Analysismentioning

confidence: 99%

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Brushless field‐excitation method for wound‐rotor synchronous machines

Bukhari

Ahmad

Akhtar

et al. 2021

Int Trans Electr Energ Syst

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Summary This paper proposes a simplified harmonic field‐excitation scheme for the brushless operation of wound‐rotor synchronous machines (WRSMs). The proposed scheme involves two inverters that are operating at different frequencies to provide an input current to the armature winding of the machine. One of these two inverters works at a frequency of 60 Hz and provides the regular three‐phase fundamental current, whereas the second inverter works at 180 Hz frequency to supply the single‐phase third‐harmonic to the common point of the start‐connected stator winding of the machine. The proposed method has the advantage that a conventional single‐phase inverter can be used for generating the third‐harmonic current which only needs to be operated at three times the frequency of the first inverter supplying the three‐phase fundamental current. The fundamental three‐phase current generates the main armature field, and the single‐phase third‐harmonic current produces a pulsating magnetomotive force, that induces electromotive force (EMF) in the harmonic winding of the rotor. The induced EMF is rectified to supply field current to the rotor and generates the rotor field. This field, when interacts with the main armature field, produces torque. The proposed brushless field‐excitation scheme for WRSMs is implemented in JMAG‐Designer version 19.1 using 2‐D finite element analysis to realize its operation and analyze its performance.

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Section: Electromagnetic Analysismentioning

confidence: 99%

“…In References 19,20, a brushless WRSM topology based on two inverters, which supplied two different magnitudes of currents to the stator winding, was proposed. In the proposed topology, the armature winding was installed using a distinct star connection distributed symmetrically in the two halves of the armature winding.…”

Section: Introductionmentioning

confidence: 99%

Brushless field‐excitation method for wound‐rotor synchronous machines

Bukhari

Ahmad

Akhtar

et al. 2021

Int Trans Electr Energ Syst

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“…This motivated researchers to explore other options that require no magnets. One of such candidates is a wound field synchronous machine (WFSM) [4]- [5]. However, this machine requires brushes, slip rings, and additional exciters, which make them unfavorable for small-and medium-scale power applications [6]- [7].…”

Section: Introductionmentioning

confidence: 99%

Simplified Brushless Wound Field Synchronous Machine Topology Based on a Three-Phase Rectifier

et al. 2021

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“…Besides this, the proposed topology also possesses a higher torque ripple and lower average torque and efficiency due to the same reason. Although these issues were addressed to some extent by designing an 8-pole, 24-slot machine in [19], the problems persist for a 4p24s machine in particular and brushless topologies based on sub-harmonic field excitation technique in general. This paper proposes a new high-efficient BL-WRSM topology based on a sub-harmonic field excitation technique that involves two distinct windings: (1) main armature winding, and (2) additional armature winding installed in the stator slots.…”

Section: Introductionmentioning

confidence: 99%

High-Efficient Brushless Wound Rotor Synchronous Machine Topology Based on Sub-Harmonic Field-Excitation Technique

et al. 2021

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This paper presents a new high-efficient three-phase brushless wound rotor synchronous machine (BL-WRSM) based on a sub-harmonic field excitation technique. In the proposed machine topology, the stator is equipped with two different three-phase windings: (1) main armature winding, and (2) additional armature winding. The main armature winding is based on a 4-pole winding configuration, whereas the additional armature winding is based on a 2-pole winding configuration. Both windings are supplied current from two different inverters, i.e., inverter-1, inverter-2, and simultaneously. Inverter-1 provides the regular input current to the main armature winding, whereas inverter-2 provides a three-phase current of low magnitude to the 2-pole additional armature winding. This generates an additional sub-harmonic component of MMF in the airgap beside the fundamental MMF. On the other side, the rotor is equipped with (1) harmonic, and (2) field windings. These windings are electrically coupled via a rectifier. The fundamental component of MMF produces the main rotating magnetic field, whereas the sub-harmonic MMF gets induced in the harmonic winding to produce harmonic current. This current is rectified to give DC to the rotor field winding to attain brushless operation. To authenticate the operation and analyze its performance, the proposed BL-WRSM topology is supported using 2-D finite element analysis (FEA) in JMAG-Designer. Later on, the performance of the proposed brushless topology is compared with the customary BL-WRSM topology to verify its high efficiency, high output torque, low torque ripple, and low unbalanced radial force on the rotor.

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Variable-speed, sub-harmonically excited BL-WRSM avoiding unbalanced radial force

Cited by 15 publications

References 11 publications

Brushless field‐excitation method for wound‐rotor synchronous machines

Brushless field‐excitation method for wound‐rotor synchronous machines

Simplified Brushless Wound Field Synchronous Machine Topology Based on a Three-Phase Rectifier

High-Efficient Brushless Wound Rotor Synchronous Machine Topology Based on Sub-Harmonic Field-Excitation Technique

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