Comparative study of electromagnetic vibration on single three-phase and dual three-phase permanent magnet machines with different winding layouts

The comparison between conventional single three-phase permanent magnet (STP-PM) machine and dual three-phase permanent magnet (DTP-PM) machine has primarily focused on performance and fault-tolerance ability. However, electromagnetic vibration behaviour is one of vital indicator for evaluating the comprehensive performance of the machine. In this paper, the mechanism of the effect on the vibration performance of the STP-PM machine and DTP-PM machine with different winding layouts is analysed. First, the coil electromagnetic force phasor diagrams with different winding layouts are given. Moreover, the harmonic distribution of the armature magnetomotive force (MMF) and air-gap electromagnetic force density (AEFD) in PM machines are analysed in detail, and vibration predictions are given. The result demonstrates that the PM machine with single-layer winding exists high amplitude of the armature MMF sub-harmonic components, especially at the first-order, while the DTP-PM machine can effectively suppress the fifth- and seventh- order harmonic components. And the AEFD amplitude at the major orders of DTP-PM machine with double-layer is the lowest which is of great significance to reduce vibration acceleration at 2f_e. Finally, the modal test and vibration measurement for a manufactured 24slot/22pole DTP-PM machine are carried out to validate the theoretical analysis and simulated results.