Electromagnetic Design and Analysis of a Novel Fault-Tolerant Flux-Modulated Memory Machine

Abstract

Abstract:Electric machines play an important role in modern energy conversion systems. This paper presents a novel brushless fault-tolerant flux-modulated memory (FTFM) machine, which incorporates the merits of a flux-modulated permanent magnet machine and multi-phase memory machine and is very suitable for applications that require wide speed ranges of constant-power operation. Due to the magnetic modulation effect, the FTFM machine can produce a large torque at relatively low speeds. Due to the usage of aluminum-nickel-cobalt (AlNiCo) magnets, this machine can readily achieve a flexible air-gap flux controllability with temporary DC current pulses. Consequently, the constant-power region is effectively expanded, and the machine's efficiency during constant-power operation is increased. Due to the multi-phase armature winding design, the FTFM machine enables lower torque ripple, increased fault tolerance ability and a higher possibility of splitting the machine power through a higher number of phases, thus the per-phase converter rating can be reduced. The design methodology and working principle of this kind of machine are discussed. The electromagnetic performances of the proposed machine are analyzed using the time-stepping finite element method (TS-FEM).

Design and Optimization of Permanent Magnet Brushless Machines for Electric Vehicle Applications

“…Since this proposed PM brushless machine is designed to operate over an extended speed range, the maximum operating speed, as well as a speed correction factor, is introduced to the initial dimension equation. Based on the conventional design method [22], it can be deduced as:…”

Flux-Modulated Permanent Magnet Machines: Challenges and Opportunities

“…Through utilizing hybrid PMs, NdFeB and AlNiCo, high efficiency flux-weakening operation can be achieved by injecting DC current pulse to change the working point of AlNiCo [58]. In order to improve fault tolerant capability, a five-phase bidirectional FMPM machine was developed to keep normal operation when open-circuit fault occurs [59], as shown in Figure 24.…”

“…Through utilizing hybrid PMs, NdFeB and AlNiCo, high efficiency flux-weakening operation can be achieved by injecting DC current pulse to change the working point of AlNiCo [58]. In order to improve fault tolerant capability, a five-phase bidirectional FMPM machine was developed to keep normal operation when open-circuit fault occurs [59], as shown in Figure 24. tion of a bidirectional FMPM machine [56], and comparative analysis shows that it can achieve 10% higher torque than its unidirectional FMPM machine counterpart shown in Figure 2b.…”

Numerical Simulation and Experimental Validation of a Flux Switching Permanent Magnet Memory Machine

“…Flux switching permanent magnet memory (FSPMM) machine is a novel flux switching permanent magnet machine that has the function of flux regulating, including the enhance flux and weaken flux [1][2][3]. Different from the traditional online flux regulating by continuous current, the flux regulating of FSPMM machine can be realized by injecting one pulse current (usually less than 1ms) into flux regulating windings, which aim is to change the work point of low-coercive-force permanent magnet materials [4][5].…”