Voltage reapplication rate control for commutation of thyristors
US4319318A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1980 |
| Grant date | Mar 9, 1982 |
| Priority date | — |
| Expiry date | Sep 15, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/096
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A circuit for commutating a thyristor (21) by shunting its current for a minimum interval, thereby removing sustaining voltage to said thyristor, then subsequently restoring voltage to said thyristor at a predetermined rate, utilizes a series combination of a commutation electronic switch (22) and an isolated dc voltage supply (23) connected in parallel with the thyristor. The voltage supply is arranged with a polarity that permits the current flowing through the thyristor in one direction to be bypassed through the series combination while the commutation switch is turned on and to reverse bias the thyristor when the commutation switch is fully on. A dv/dt control circuit (24) limits the rate of rise of voltage across the commutation switch (22) as it is turned off in response to a command input signal. The dv/dt control circuit is comprised of a constant current drive (31) and a capacitor (32) connected between the output terminal of the commutation switch and the control input terminal of the commutation switch. The thyristor may be a triac (40) with two commutation switches (42, 43), one for current of each polarity, or with a single commutation switch (55) and a bridge circuit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.