Turn-off circuit
US5187652A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 26, 1991 |
| Grant date | Feb 16, 1993 |
| Priority date | — |
| Expiry date | Nov 26, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M5/4505
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In circuits with self-commutation such as, for example in inverters (4) for feeding an asynchronous machine (7), a short-time turn-off current impulse is taken from a turn-off capacitor (C1) of a turn-off or common turn-off circuit (3) for interrupting the thyristor current of the inverter. The turn-off circuit (3) connected to the direct-current side (8, 9) of the inverter (4) exhibits a first series circuit of the turn-off capacitor (C1) and a first electrical valve (T2, D2). In a branch in parallel with the turn-off capacitor (C1), a ring-around reactor (L1) with an inductance of 0.1 mH is connected in series with a second thyristor (T1). A further third thyristor (T3) is connected in antiparallel with the second thyristor (T1). A ring-around process initiated by the firing of the second thyristor (T1) is interrupted after a half period. After a freely selectable time, the third thyristor (T3) can be fired and the full resonance cycle can be concluded. As a result, the hold-off interval or minimum turn-off period for the thyristors can be achieved with a comparatively very small ring-around reactor (L1).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.