During the past five years, cogging torque in HDD spindle motors has decreased drastically as designers and manufacturers have developed a better understanding of the cogging phenomenon. This paper examines various methodologies of cogging torque reduction. Timing techniques such as dead zones and tooth notching, smoothing techniques such as sinusoidal magnetization, and geometric techniques su...

In many machines, where permanent magnets are used, the effects due to cogging torque generated by permanent magnets (PMs) aggravate the output characteristics of the machines. This paper presents the method for reducing cogging torque in surface-mounted permanent magnet synchronous motor (SPMSM). A new cogging torque suppression method called axial pole pairing is proposed. Compared to convent...

High performance motor drive applications require permanent–magnet synchronous motors that produce smooth torque with very low components of cogging torque. To fulfil such demands a variety of design techniques can be used to reduce or even eliminate cogging torque components. Rotor design techniques are in comparison to the stator ones much more effective, but their effectiveness depend consid...

As one of the main parasitic parameters in permanent magnet (PM) synchronous machines (PMSMs), cogging torque is the main component of the torque ripple, which has always been the handicap in the high-performance, low-speed drive systems. Over the last two decades, various methods have been proposed to decrease the cogging torque in both radial-flux and axial-flux PMSMs. Among these methods, st...

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging ...

Abstract: A novel modular arc-linear flux-switching permanent-magnet motor (MAL-FSPM) used for scanning system instead of reduction gearboxes and kinematic mechanisms is proposed and researched in this paper by the finite element method (FEM). The MAL-FSPM combines characteristics of flux-switching permanent-magnet motor and linear motor and can realize the direct driving and limited angular mo...

In Permanent-Magnet Synchronous Generators (PMSGs) the reduction of cogging torque is one of the most important problems in their performance and evaluation. In this paper, at first, a direct-drive vertical-axis wind turbine is chosen. According to its nominal value operational point, necessary parameters for the generator is extracted. Due to an analytical method, four generators with differen...

The utility of PM-BLDC machines is extending its tentacles in industrial arena. The key features of BLDC machines include high starting torque density and extending speed range, though the cogging torque is a threat for its performance. Various techniques have been devised to minimize cogging torque, out of which two approaches Bifurcation and Slot Opening methods have been focused in this pape...

Cogging torque is the major limitation of axial flux permanent magnet motors. The reduction of cogging torque during the design process is highly desirable to enhance the overall performance of axial flux permanent magnet motors. This paper presents a double-layer magnet design technique for cogging torque reduction of axial flux permanent magnet motor. Initially, 250 W, 150 rpm axial flux brus...