Design optimization of ironless multi-stage axial-flux permanent magnet generators for offshore wind turbines

Abstract

Design optimization of ironless multi-stage axial-flux permanent magnet generators for offshore wind turbines Direct-driven ironless-stator machines have been reported to have low requirement to the strength of the supporting structures. This feature is attractive for offshore wind turbines where lightweight generators are preferred. However, to produce sufficient torque, ironless generators are normally designed at large diameters, which can be a challenge to the machine structural reliability. Ironless Multi-Stage Axial-Flux Permanent Magnet Generator (MS-AFPMG) embraces the advantages of ironless machines but has relatively small diameter. The objective of this article is to present the design optimization and performance investigation of the ironless MS-AFPMG. An existing design strategy, which employs 2D and 3D static finite element analyses and genetic algorithm for machine optimization, is improved with the aim to reduce the calculation load and calculation time. This improved design strategy is used to investigate the optimal ironless MS-AFPMG. Some intrinsic features of this kind of machine are revealed.

Multiple-airgap iron-cored direct-driven permanent magnet wind generators

“…High axial forces in AF machines with iron cores lead to mechanical complexity and make it difficult to produce such machines for high powers. When stators in multi-disc machines are ironless, like in [13] and [14] then there exist no axial forces and the concept can be considered in high power DD applications. This study will focus on RF machine with iron cores, leaving ironless designs and multidisc designs outside the scope.…”

A Review on Transverse Flux Permanent Magnet Machines for Wind Power Applications

“…The comparative study was performed for various 5 MW topologies and 9-phase AFPM machine with concentrated winding [49]. The 10 MW iron-less AFPM machine was examined for offshore wind turbines with especial consideration on weight minimization [50].…”

Structural Design and Multi-objective Optimization of Planetary Frame for 6T40E Automatic Transmission

“…In the above formula, B, m, N and C represent the outer ring thickness of tooth width, magic and number of gears respectively, Z a , Z b and Z c represent the number of teeth of sun gear, inner ring gear and planetary gear respectively [12] .…”

“…Because the designed double-row planetary gear train is a two-stage planetary gear train, the total transmission efficiency η p of the planetary gear train is determined by the product of the transmission efficiencyη 1 andη 2 of the two-stage planetary gear train. Therefore, the formula for calculating transmission efficiency is as follows: 12 Where ε is coincidence degree, f k is the meshing friction factor, φ n H is bearing loss coefficient [13] .…”