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Reduction of bearing currents by using asymmetric, space-vector-based switching patterns
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| Author(s) |
J. Zitzelsberger; W. Hofmann |
| Abstract |
The phenomena of bearing currents is known for a long period. Especially those which are caused by
magnetic asymmetries have been investigated since the beginning of the 20th century. Nowadays new
kinds of bearing currents can be observed in inverter fed induction drives. Investigations done on
these effects show that the switched operational mode – especially of voltage source inverters –
causes a high frequency common mode voltage (CMV). This voltage supplies the common mode circuit
of an electrical machine in which the bearings are a part of. Therefore, to reduce the occurrence
of bearing currents it is necessary to avoid or - at least - to minimise the common mode voltage in
drive applications fed by voltage source inverters. A novel principle for such a purpose is the space
vector based modulation with sequentially positioned pulses (SPP). With this modulation it is possible
to reduce both the number of edges within the CMV and its amplitude to a great extent without influencing
the modulation index. The present paper summarises the ideas which stand behind the principle
of SPP and gives an overview over the major dependence's from characteristics of the drive system.
Moreover, the functionality and the compatibility to standard inverter fed drives is shown by
means of simulations and measurements. |
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| Filename: | EPE2003-PP0131 - Zitzelsberger |
| Filesize: | 369.8 KB |
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| Type |
Members Only |
| Date |
Last modified 2003-10-15 by Unknown |
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