High frequency inverter fault protection system
US4435749A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 26, 1982 |
| Grant date | Mar 6, 1984 |
| Priority date | — |
| Expiry date | Feb 26, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/122
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fault protection system for a balanced thyristor capacitor/inverter half-bridge which generates a high frequency oscillating voltage from full-wave rectified line voltage is disclosed. Following the detection of thyristor over-current and the removal of transformer-coupled, alternating, gated drive signals from the thyristors by means of logic and control circuitry, the natural ringing of a charged resonant circuit coupled across the inverter half-bridge causes thyristor commutation and inverter shutdown. The resonant circuit and inverter half-bridge are isolated from the line voltage source during the fault recovery cycle by means of an inductance, the size of which is selected to greatly exceed the total inductance in the inverter bridge-resonant circuit system to avoid saturation until the power thyristors have been given sufficient time to turn off. Thyristor minimum commutation voltage is provided by a low voltage power supply coupled to the inverter half-bridge via the isolation inductance and which is energized by an output transformer coupled to the inverter half-bridge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.