Cogging torque minimisation in FSPM machines by right‐angle‐based tooth chamfering technique

Abstract

Cogging torque in flux-switching permanent magnet (FSPM) machines dominates the whole torque ripples due to its special doubly salient structure and high air-gap PM flux density. In this study, the chamfering method of right angles is utilised in both stator and rotor sides of FSPM machines to suppress the cogging torque. First, an analytical expression of cogging torque, taking the influence of the introduced right angles into consideration, is derived. On the basis of the derived model, the optimal dimensions of right angles are obtained and verified by both finite element analysis and experiments. Besides, the impacts of the proposed technique on phase electro-motive force and electromagnetic torque are also evaluated. The predicted results indicate that the proposed technique can significantly reduce cogging torque in FSPM machines with negligible reduction of average torque.

Performance modifications and design aspects of rotating flux switching permanent magnet machines: a review

“…This method is regularly characterised by a radius, known as 'chamfering radius'. However, additional investigations have been made on modified chamfering shapes, such as right-angles chamfering on both rotor and stator teeth [71].…”

Transient analysis with coupled field-circuit model and experimental assessment of a PMSG used in small-scale wind turbine for water heating purpose

“…Furthermore, the parameter of cogging torque becomes greatly more of an issue in especially low-speed wind turbine applications and electric power steering systems [27,28]. Reducing the cogging torque helps to reduce torque ripple, mechanical vibration and acoustic noise [29]. Herewith, we provide a smooth electromagnetic torque [30][31][32].…”

A novel cogging torque measurement method for multi slot/pole permanent magnet motor

“…Yet it requires a fine mesh discretisation and cannot think over manufacturing tolerances, such as static and dynamic rotor eccentricities [21][22][23], imperfections in structures [18,23], etc. There are several possible ways to measure the cogging torque, for example, conventional torque transducer [5,[24][25][26], special torque transducer [27][28][29], torque observer [13,30], etc. The pulsation torque with zero average value cannot be accurately measured by conventional torque transducers.…”