Means for controlling a forced commutated ac-to-dc electric rectifying circuit to avoid commutation failure
US4467408A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1982 |
| Grant date | Aug 21, 1984 |
| Priority date | — |
| Expiry date | Dec 29, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/293
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A phase-controlled ac-to-dc rectifying circuit includes a pair of alternately conducting main controllable electric valves and cyclically operative forced commutation means for turning off the main valves. The forced commutation means comprises a pair of auxiliary controlled rectifiers respectively connected, in circuit with a commutating capacitor, across the main valves, and the auxiliary rectifiers are alternately turned on in response to periodic trigger signals that are normally produced by associated control means. Protective means is provided for inhibiting the trigger signals when the magnitude of voltage across the commutating capacitor is lower than a critical level which depends on the magnitude of the current being conducted by the main valves, thereby avoiding a risk of commutation failure due to low capacitor voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.