Novel design of a coreless axial-flux permanent-magnet generator with three-layer winding coil for small wind turbines

• Published in: IET renewable power generation Vol. 14; no. 15; pp. 2924 - 2932
• Main Authors: Yao, Wu-Sung, Cheng, Ming-Te, Yu, Jyh-Cheng
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 16.11.2020
• Subjects: air gap magnetic flux distribution analysis; air gaps; axial‐flux permanent‐magnet design; benchmark generator; coil shape variation; coils; coreless axial‐flux permanent‐magnet generator; experimental design; finite element analysis; flattened winding coil sets; generated power; generator design; integrated flatten coil sets; layers stator; magnetic fields; magnetic flux; parameter design; permanent magnet generators; power 300.0 W; prototype generator; Research Article; rotors; stators; three‐layer winding coil sets; three‐phase three layers; wind turbine application; wind turbines; winding imperfection; windings; magnetic flux; coil shape variation; winding imperfection; generator design; axial-flux permanent-magnet design; layers stator; air gaps; power 300.0 W; benchmark generator; wind turbine application; three-layer winding coil sets; windings; prototype generator; experimental design; coreless axial-flux permanent-magnet generator; rotors; coils; magnetic fields; flattened winding coil sets; integrated flatten coil sets; permanent magnet generators; finite element analysis; generated power; parameter design; stators; three-phase three layers; wind turbines; air gap magnetic flux distribution analysis
• ISSN: 1752-1416; 1752-1424
• DOI: 10.1049/iet-rpg.2019.0908

This study presents a novel design of the three-layer winding coil sets of a coreless axial-flux permanent-magnet generator applied to small wind turbines. The proposed generator design consists of two rotors and an integrated stator with flattened winding coil sets of three-phase three layers connected using a wye configuration. An analytical model of the inductance and resistance of the coil set is described to analyse the influence of the coil shape variation due to winding imperfection. The air gap magnetic flux distribution analysis shows the advantage of the integrated flatten coil sets compared with a typical stack up three layers stator. An experimental design is conducted for the parameter design of geometric variables to optimise the output power of the proposed axial-flux permanent-magnet design. A prototype generator is then constructed to compare with a benchmark generator that has a rated output power of 300 W at 800 rpm. The proposed design outperforms the benchmark generator by 26.5% in terms of generated power at a typical driving rotation velocity of 500 rpm for a small wind turbine, and demonstrates a superior performance at a lower driving speed range, which is particularly important in a small wind turbine application.