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Description
In order to improve the fault tolerant (FT) capability suitable for high reliability operation, FT teeth and concentrated windings are designed in two FT flux-switching permanent-magnet machines, namely 10/18-pole and 10/19-pole. However, they still suffer from vibration and noise due to radial force fluctuation. This paper compares the vibration characteristic of both machines. Because odd rotor pole is adopted, the 10/19-pole machine offers less pulsating torque than the 10/18-pole one due to its more symmetric back electromotive force and reduced cogging torque. The total harmonic distortion is 3.9% for 10/19-pole machine, and 7.7% for 10/18-pole one. The cogging torque is 0.066 Nm for the 10/19-pole machine, and 0.757 Nm for the 10/18-pole one. The dominant radial pressure harmonic order is just the pole number for both machines. For 10/18-pole machine, only even harmonics are excited, the lowest order of harmonics is 2. For 10/19-pole machine, even and odd harmonics are all excited. Especially, the first order harmonic is unbalance component which can induce distinct vibration. The stator deformation shows that the dominant vibration modes of 10/18-pole machine are 2nd and 4th. However, for 10/19-pole machine, the dominant modes are 2nd and 1st. The 1st mode generates unbalance deformation, hence induces more severe vibration than that of the 10/18-pole one, although the 10/18-pole machine suffers from higher torque ripple. The measured acceleration is about 1.8 m/s2 for the 10/19-pole machine, and 0.4 m/s2 for the 10/18-pole one. Measurement result is coincided with the predicted one. It indicates that machines with a low torque ripple do not guarantee low vibration. In terms of vibration, the lower-order radial pressure harmonics with high amplitudes have more influence than the torque ripple. Moreover, the unbalance component will aggravate vibration. Detailed results and discussions will be given in full paper.
| Submitters Country | China |
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