A Coaxial Magnetic Gear With Consequent-Pole Rotors

IEEE Trans. on Ind. Applicat.

2019

This paper provides a comprehensive analysis of performance difference among various kinds of flux reversal permanent magnet (FRPM) machines having different PM arrangements. Four PM arrangement types are firstly identified by the number and relative polarities of PMs on the stator teeth, and their influence on equivalent pole-pair number of armature winding and working harmonics of air-gap field is revealed. Then, the torque variation against rotor pole number of each PM arrangement is analyzed. Detailed electromagnetic performance of four PM arrangements with 14-pole rotor is compared. It shows that the FRPM machine, in which four PM pieces are mounted on each stator tooth and two adjacent magnets on different stator teeth are of opposite polarities, offers the highest torque density and the highest efficiency, which makes it promising in low-speed high-torque applications. In addition, four prototype machines are manufactured and tested to validate the findings. Index Terms-flux reversal, magnet arrangement, torque proportion, winding factor

Section: Working Principle Of Frpm Machines With Different Pm Arrmentioning

confidence: 99%

Influence of Adjacent Teeth Magnet Polarities on the Performance of Flux Reversal Permanent Magnet Machine

IEEE Trans. on Ind. Applicat.

2019

“…Since the reluctance torque of FRPM machine is negligible [3], the average torque of the machine can be derived as…”

Section: B Analytical Derivation Of Machine Performancementioning

confidence: 99%

“…ITH the help of high-energy permanent magnet (PM) materials, the PM machines have now been widely used in various industrial applications, thanks to their superior torque density, efficiency, and topology diversity [1][2][3]. For low-speed and high-torque applications such as wind power, marine propulsion and rail traction etc., the direct-drive PM machines are regarded as promising candidates due to their simplified mechanical structure, high reliability, and less vibration and noise.…”

Section: Introductionmentioning

confidence: 99%

Optimal Number of Magnet Pieces of Flux Reversal Permanent Magnet Machines

IEEE Trans. Energy Convers.

2019

Self Cite

This paper aims to comprehensively analyze the influence of number of permanent magnet (PM) pieces on electromagnetic performance of flux reversal permanent magnet (FRPM) machines. Firstly, the unified analytical model of FRPM machines having different numbers of PM pieces is established, from which the optimal number of PM pieces and the corresponding rotor pole number can be identified. It shows that by employing the optimal number of PM pieces instead of the conventional two on each stator tooth, additional back-EMF component can be generated which is beneficial to boost the machine performance. Then, the influence of critical design parameters including stator slot opening ratio, split ratio and stator slot number is investigated, providing a guidance to the design of FRPM machines aiming at maximum output torque. In addition, both finite element analyses and experimental tests are conducted to verify the analytical analyses. For 6-slot-stator FRPM machines, experimental results show that more than 40% higher output torque can be achieved in the machine with optimal number of PM pieces when compared to the conventional one.

“…For CPM machines, the discrepancies between the results are larger especially for Type4 (the measured value is around 80% of the FE-predicted value). In addition to manufacturing imperfection, this phenomenon can be attributed to the large end-effects in CPM topologies [18,19], and some techniques should be further considered to reduce the effect. Despite the large end-effects, the improved back-EMFs of CPM topologies can still be verified since both CPM machines have higher measured back-EMFs than their SPM counterparts.…”

Section: Experimental Validationmentioning

confidence: 99%

Analysis of Flux-Reversal Permanent-Magnet Machines With Different Consequent-Pole PM Topologies

2018

IEEE Trans. Magn.

This paper comprehensively studies the electromagnetic performance of flux reversal permanent magnet (FRPM) machines with different consequent-pole PM (CPM) topologies. Four CPM topologies are firstly introduced and classified by different numbers of PM pieces and PM locations on stator teeth. Then, the distribution and working harmonics of air-gap flux density of each CPM topology are analyzed and compared, and the CPM topology with the highest torque density is identified. The influence of critical design parameters on machine performance is also parametrically investigated. By comparing the torque performance of CPM topologies with their surface-mounted PM (SPM) counterparts, the advantages of CPM topologies, i.e. torque improvement and magnet volume reduction, are clearly revealed. Four FRPM prototypes are manufactured and tested to verify the analyses.