Brushless
            <scp>field‐excitation</scp>
            method for
            <scp>wound‐rotor</scp>
            synchronous machines

Bukhari, Syed Sabir Hussain; Ahmad, H.; Akhtar, Faheem Hassan; Ro, Jong‐Suk

doi:10.1002/2050-7038.12961

Cited by 6 publications

(2 citation statements)

References 23 publications

(25 reference statements)

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“…From Equation ( 12), it can be seen that the induced EMF in the harmonic winding of the rotor is three times as much as the synchronous angular frequency. The induced EMF (e h ) in the rotor harmonic winding is rectified by a rotating rectifier to supply dc to the rotor field winding to archive brushless operation for WFSM [19,20].…”

Section: Machine Topology and Working Principlementioning

confidence: 99%

Novel Single Inverter-Controlled Brushless Wound Field Synchronous Machine Topology

et al. 2021

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This paper proposes a novel brushless excitation topology for a three-phase synchronous machine based on a customary current-controlled voltage source inverter (VSI). The inverter employs a simple hysteresis-controller-based current control scheme that enables it to inject a three-phase armature current to the stator winding which contains a dc offset. This dc offset generates an additional air gap magneto-motive force (MMF). On the rotor side, an additional harmonic winding is mounted to harness the harmonic power from the air gap flux. Since a third harmonic flux is generated in this type of topology, the machine structure is also modified to accommodate the third harmonic rotor winding to have a voltage induced as the rotor rotates at synchronous speed. Specifically, four-pole armature and field winding patterns are used, whereas the harmonic winding is configured for a twelve-pole pattern. A diode rectifier is also mounted on the rotor between the harmonic and field windings. Therefore, the generated voltage on the harmonic winding feeds the current to the field winding for excitation. A 2D-finite element analysis (FEA) in JMAG-Designer was carried out for performance evaluation and verification of the topology. The simulation results are consistent with the proposed theory. The topology could reduce the cost and stator winding volume compared to a conventional brushless machine, with good potential for various applications.

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Section: Machine Topology and Working Principlementioning

confidence: 99%

Novel Single Inverter-Controlled Brushless Wound Field Synchronous Machine Topology

et al. 2021

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“…In addition, at the same time, it increases the power density of the machine as a solution to the inherent problem of conventional brushless WRSM. In [6][7][8][9][10], more compact machine systems have been investigated by generating and utilizing harmonic flux to induce a voltage in harmonic winding on the rotor with a conventional stator structure. These types of machines are compact in size as they remove the need to install the exciter field winding on the stator.…”

Section: Introductionmentioning

confidence: 99%

Cost-Effective Scheme for a Brushless Wound Rotor Synchronous Machine

Sirewal

Bukhari

2021

WEVJ

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This paper proposes a new scheme for a brushless wound rotor synchronous machine (WRSM) by generating an additional, two-pole component of magneto-motive force (MMF) with a series-connected additional three-phase winding with the armature three-phase winding. Unlike existing brushless excitation schemes, which use the inverter to inject harmonic currents in the stator windings, the proposed scheme uses series-connected additional winding on the stator with the armature winding in a two-pole configuration. Consequently, as the current flows in the armature winding, it creates a fundamental rotating air gap flux to interact with the field flux. At the same time, additional rotating flux is created from the additional three-phase winding, which cannot synchronize with the field winding. This additional flux can cause the induction of a voltage in a winding with exactly the same number of poles. For this purpose, a harmonic winding is installed in the rotor along with the field winding connected through a diode bridge rectifier, in order to feed the direct current (DC) to the field winding for rotor excitation without an input current from the brush-slip-ring assembly. The 2D finite-element analysis (FEA) was performed to validate the brushless operation of the proposed machine system.

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Novel Hybrid Consequent-Pole Brushless Wound Rotor Synchronous Machine for Improving Torque Characteristics

Bukhari

2022

IEEE Access

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This article introduces a hybrid consequent-pole brushless wound rotor synchronous machine (CP-BL-WRSM). The CP-BL-WRSM installs permanent magnets (PMs) on the alternative rotor poles. Compared with the conventional BL-WRSM and permanent magnet-assisted brushless WRSM (PM-BL-WRSM), the proposed machine provides advantages of high average output torque, high maximum torque, and high starting torque. In addition, the proposed CP-BL-WRSM's torque ripple is also lower than the conventional brushless WRSM. The volume of PM in the CP-BL-WRSM machine is lower than the conventional permanent magnet synchronous machines (PMSMs) and PM-BL-WRSM. In this brushless topology, the machine uses three-phase stator windings powered by a single inverter, which provides a unique armature current to the stator windings that comprises of fundamental and third-harmonic components. The fundamental current component is used to generate the main stator field, and the third-harmonic current component is used to induce a harmonic current in the harmonic winding. A diode rectifier installed on the rotor is used to rectify the harmonic current. After the rectification, a direct current (DC) is injected into the field winding of the rotor to form a rotor magnetic field and achieve brushless operation. In order to verify the operation of the proposed CP-BL-WRSM topology and analyze its performance, 2-D finite element analysis (FEA) was used in JMAG-Designer. Finally, the performance of the proposed CP-BL-WRSM topology was compared with the conventional BL-WRSM topology and PM-BL-WRSM topology to verify its higher starting torque, higher average torque, and higher maximum torque and higher minimum torque. The proposed topology can replace the existing highly expensive PM synchronous machines (PMSMs) due to its less PM volume and conventional BL-WRSMs due to its better performance.INDEX TERMS Brushless excitation, synchronous machine, consequent-pole, harmonic winding, 2-D finite element analysis (FEA).

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Brushless field‐excitation method for wound‐rotor synchronous machines

Cited by 6 publications

References 23 publications

Novel Single Inverter-Controlled Brushless Wound Field Synchronous Machine Topology

Novel Single Inverter-Controlled Brushless Wound Field Synchronous Machine Topology

Cost-Effective Scheme for a Brushless Wound Rotor Synchronous Machine

Novel Hybrid Consequent-Pole Brushless Wound Rotor Synchronous Machine for Improving Torque Characteristics

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