Abstract
A method for determining output currents of a three-phase frequency converter comprising a voltage intermediate circuit and three power switch pairs constituting an output of the frequency converter, wherein the power switches constituting a pair are coupled in series between a positive and a negative busbar of the voltage intermediate circuit so that a midpoint of each switch pair constitutes a phase output of the frequency converter.; The method comprises, during use of the frequency converter, steps of forming a voltage reference vector for the output power switches such that only two switch pairs are modulated during one modulation sequence, controlling said two switch pairs to implement a voltage reference vector during the modulation sequence by using one zero vector, measuring current of the voltage intermediate circuit of the frequency converter at a predetermined moment in the modulation sequence, and changing actively, during use of the frequency converter, the zero vectors to be used in the modulation sequences.
| Original language | English |
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| Patent number | US2005152165 |
| IPC | H02P 27/ 12 A I |
| Priority date | 19/12/2003 |
| Publication status | Published - 14 Jul 2005 |
| MoE publication type | H1 Granted patent |