Axial Field Flux-switching Machine Research Articles

Optimal Design and Analysis of the Novel Low Cogging Torque Axial Flux-Switching Permanent-Magnet Motor

The axial field flux-switching permanent-magnet machine (AFFSPM) is one of the most efficient machines which is appropriate for high torque and low-speed direct-drive applications. In this paper, the novel axial field flux switching machine with sandwiched permanent magnet (AFFSSPM) is proposed in order to increase torque density and decrease cogging torque. The proposed model equipped with an advanced phase-group concentrated-coil winding to obtain a unity displacement winding factor. Two three-phase 6-stator-slot (S)/10-rotor-pole (P) and 12(S)/19(P) configurations of the proposed model are investigated. Some specific design issues, including the sandwiching pole angle, the stator tooth angle, and the rotor pole angle have been optimized to obtain the maximum torque density and minimum cogging torque by artificial neural network and non-sorting genetic algorithm II. Moreover, the static electromagnetic characteristics are investigated. Compared with the conventional AFFSPM and 6(S)/10(P) AFFSSPM, the 12(S)/19(P) proposed machine shows higher torque density, lower cogging torque, and higher level of fault-tolerant capability. In order to improve the dynamic performance of the AFFSSPM motor, a space vector modulation-direct torque and flux control (SVM-DTFC) scheme is proposed. The AFFSSPM motor exhibits excellent dynamic performance with proposed scheme.

Design and prototyping of the novel axial flux-switching permanent-magnet motor

PurposeThe purpose of this paper is to propose a novel axial field flux-switching machine with sandwiched permanent magnets. It is one of the most efficient machines which is appropriate for high-torque and low-speed direct-drive applications. The proposed model is equipped with an advanced phase-group concentrated-coil winding to obtain a unity displacement winding factor. Two configurations of the proposed motors with 6-stator-slot (S)/10-rotor-pole (P) and 12S/19P are investigated. These two structures are compared with optimized a conventional axial-field flux-switching permanent-magnet (CAFFSPM) machine. Unity displacement winding factor increases the back-EMF and electromagnetic torque. Moreover, the prototype 12S/19P motor is built to verify the design.Design/methodology/approachThe torque equation is obtained and the dimensions of the two proposed motors are determined. Some specific design issues, including the stator/rotor pole sandwiching pole angle, the stator tooth angle and the rotor pole angle have been optimized to minimize the cogging torque while maintaining the high torque density by means of response surface methodology (RSM) and 3-D finite element model of the machine.FindingsTo improve the performance, especially at high torque density, low cogging torque and high level of fault-tolerant capability, the 12S/19P axial field flux-switching sandwiched permanent-magnet (AFFSSPM) motor is proposed. Based on the optimized design, a prototype of the 12S/19P AFFSSPM motor is fabricated and tested. It is found that the experimental results validate the 3-D finite element method (FEM) simulation results.Originality/valueThe AFFSSPM motor is one of the most efficient motors, but the 12S/19P AFFSSPM motor with sandwiched permanent magnet and unity displacement winding factor has not been specially reported to date. Thus, in this paper, the authors report on optimal design of a novel axial flux-switching sandwiched permanent-magnet machine for electric vehicles and fabricate a prototype of the 12S/19P AFFSSPM motor.

Minimum‐copper‐loss control of hybrid excited axial field flux‐switching machine

Hybrid excited axial field flux-switching machine (HEAFFSM) with permanent magnets (PMs) and excitation windings in its stator is a novel hybrid excited flux-switching PM machine. The HEAFFSM combines the advantages of the hybrid excited synchronous machine and flux-switching PM machine. In this study, the topology and operating principles of the HEAFFSM are analysed, and the electromagnetic characteristics (including the winding inductances, flux, and cogging torque) are obtained by the three-dimensional finite-element method. On the basis of the vector control method, the mathematical model of the HEAFFSM is deduced, and the operating performance of the HEAFFSM across its entire operating range is investigated. A new minimum-copper-loss (MCL) control strategy for the HEAFFSM drive system, which can operate in both flux-enhancing and flux-weakening conditions, is proposed and compared with the traditional control. The experimental results demonstrate that the MCL strategy maximises the range of speed regulation while minimises the copper loss of the HEAFFSM drive system. Moreover, the flux-regulation capability and high power/torque density of the HEAFFSM are validated.

Design and Analysis of a New HTS Axial-Field Flux-Switching Machine

This paper proposes a new high-temperature superconductor (HTS) axial-field flux-switching machine with the merit of high power density for wind energy conversion. The key is to introduce a kind of modular racetrack cooling Dewar with static seals to replace the one with dynamic seals used in the conventional rotor excitation HTS machine. Also, the effects of rotor relative positions of the proposed machine on the back electromotive force are discussed. By using finite-element analysis, the machine performances are analyzed. Hence, the validity of the proposed machine is verified.