Power conversion circuit for synthesizing a sinewave with programmed amplitude control
US4520437A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1983 |
| Grant date | May 28, 1985 |
| Priority date | — |
| Expiry date | Jul 14, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/53873
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A waveform synthesizer is controlled in response to a stored program control utilizing tabular data stored in memory as the basis for generating timing signals to drive the power switching devices of the synthesizer. A plurality of tables of differing modulation indices define rated current output and a below rated current output. The table defines rated level output timing signals as both pulse width and frequency modulated to reduce harmonics. Various overload conditions result in selection of different modulation indices or a total current shutdown. A high peak current overload results in a halt in a progressive upward selection of modulation indices during start-up. A high average current overload results in a reduction in modulation indices until the overload has cleared. A low converter voltage signal caused by current limiting in the converter is detected and also used to reduce the modulation index so that less DC current is drawn from the converter and operation is maintained near the maximum average output power capability of the converter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.