Switched-flux machines with hybrid NdFeB and ferrite magnets. Issue 2 (7th March 2016)

• Record Type: Journal Article
• Authors: Afinowi, I.A.A.; Zhu, Z.Q.; Guan, Y.; Mipo, Jean-Claude; Farah, P.
• Editors: Zhu, Z.Q.
• Is Part Of: Compel. Volume 35:Issue 2(2016)
• Page Start: 456
• Page End: 472
• Publication Date: 2016-03-07
• Subjects: Low cost -- Brushless AC machine -- Doubly salient -- Fractional-slot winding -- Hybrid-magnet machines -- Switched-flux machines -- Synchronous permanent-magnet machines -- Novel topology -- Parallel excited -- Series excited; Electrical engineering -- Data Processing -- Periodicals; Electrical engineering -- Mathematics -- Periodicals; Electrical engineering -- Periodicals; Electronics -- Data Processing -- Periodicals; Electronics -- Mathematics -- Periodicals; 621.3
• DOI: 10.1108/COMPEL-03-2015-0112
• Languages: English
• ISSNs: 0332-1649

Abstract

Abstract : Purpose: – The purpose of this paper is to comparatively study the conventional, i.e. single magnet, and novel hybrid-magnet switched-flux permanent-magnet (HMSFPM) machines. Design/methodology/approach: – The HMSFPM machines utilize two magnet types, i.e. low-cost ferrites and NdFeB. Thus, a set of magnet ratios (?), defined as the quotient of the NdFeB volume to the total PM volume, is introduced. This allows any desired performance and cost trade-off to be designed. Series- and parallel-excited magnet configurations are investigated using 2-dimensional finite element analysis. Findings: – The torque of the HMSFPM machines is lower than the NdFeB SFPM machine but the flux-weakening performance is improved for similar machine efficiency. If the machine dimensions are unconstrained, the HMSFPM machines can have the same torque for reduced material costs and a moderate increase in machine dimensions. Ferrite SFPM machines have the lowest cost for the same torque but a significant increase in machine dimensions is required. Finally, the series-excited HMSFPM machine is the preferred over the parallel-excited HMSFPM machine because it has superior demagnetization withstand capability. Research limitations/implications: – Mechanical and winding eddy current losses are not considered in the efficiency map calculations. Originality/value: – The NdFeB SFPM, ferrite SFPM, series-excited HMSFPM, and the parallel-excited HMSFPM machines are compared for their electromagnetic performance, flux-weakening, PM demagnetization, efficiency, and material costs.