| 摘要 |
If it is desired to stop the converter in a converter having a current [sic] intermediate circuit, by reducing the frequency to zero, then the commutating capacitors must be adequately charged in the correct polarity for starting operation again. To this end, if the frequency falls below a predetermined frequency limit, on the one hand the intermediate circuit current is limited to a constantly predetermined value, and on the other hand the invertor is operated at an increased commutating frequency until a predetermined phase angle in the commutation cycle is reached. When this predetermined phase angle is reached, the commutation cycle is stopped and the converter is blocked. There is then so much energy stored in the invertor that the commutation cycle can be started again at any time at this predetermined phase angle. <IMAGE>
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