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The classical switching‐table‐based direct power control usually employs one active voltage vector during the whole sample period, which will bring distinct current harmonics and large power ripple. This paper proposes an improved deadbeat direct power control for a dual three‐phase permanent magnet synchronous generator. The deadbeat control of both active power and reactive power is employed to calculate the duty cycle of the active vector. By this way, the active and reactive power can follow the references as much as possible during each sample period. Then a weight coefficient is introduced and its effects on the steady‐state performances of active and reactive power are analysed. With this proposed method, the current harmonics and power ripple are suppressed considerably. Meanwhile, the simple structure and fast dynamic response are preserved. The experimental results validate the effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

The high variable flux density in the air‐gap of fault‐tolerant flux‐switching permanent‐magnet (FT‐FSPM) machine results in rich harmonics of the magnetic field, thus generating large vibration and noise. This study proposes two novel FT‐FSPM machines which can effectively reduce the radial pressure, thus reducing the vibration and noise. First, the radial pressure of the initial FT‐FSPM machine is analysed. Second, the novel proposed FT‐FSPM machines are introduced and analysed. Third, the electromagnetic performance, including back electromotive force, output torque, inductance, and radial pressure harmonics, of the initial and the two proposed machines are compared by finite element method. Then, the vibration modes with corresponding natural frequencies are predicted. The vibration and noise are simulated by boundary element method. Finally, the effectiveness of the low‐noise design is verified by measurement results. [ABSTRACT FROM AUTHOR]

Permanent‐magnet (PM) segmentation is a plain and valid way for eddy current (EC) loss reduction in fractional‐slot concentrated‐winding (FSCW) machines and it has no passive effect on the machine itself. In this study, compared with PM asymmetrical segmentation, the authors prove that symmetrical segmentation adopted by most scholars, in general, is the optimal choice by using both analytical method (AM) and time‐stepped transient finite‐element method (FEM), when the skin effect is neglected. Furthermore, two surface‐mounted PM machines with FSCW are proposed to investigate the effect of PM symmetrical segmentation on EC loss in rotor PMs. The actual effect of PM segmentation is to cut off the EC path and increase the resistance value in return circuit, thus decreasing EC density in PMs. In addition, some theoretical expressions evaluating the EC loss with consideration of magnet segmentation effect are derived step by step. Finally, Maxwell FEM software is used to verify the theoretical analysis, showing that the proposed AM is able to accurately predict the EC loss with different segmented numbers. [ABSTRACT FROM AUTHOR]

This study investigates the vibration behaviour of a fault‐tolerant flux‐switching permanent‐magnet (FT‐FSPM) machine due to electromagnetic origins. The FT‐FSPM machine adopts fault‐tolerant teeth and odd rotor pole to obtain more symmetric back electromotive force and reduced cogging torque. However, this topology suffers from high local magnetic force and unbalanced radial force, thus producing significant vibration and noise. In order to predict the vibration characteristic generated by the structure, electromagnetic and structural models are developed. First, the air‐gap field is qualitatively analysed by using the rotor permeance to modulate the magnetomotive force. Second, the radial forces during healthy and faulty operations are compared by using finite element method. Then, the most significant vibration modes are calculated to determine how the machine is excited. Furthermore, the vibration behaviour of the FT‐FSPM machine under healthy and faulty conditions is predicted by structural analysis. Finally, the experimental measurements are given for verification. [ABSTRACT FROM AUTHOR]