Regulated AC power system energized by variable speed prime mover
US4992920A · kind A · utility
Inventor
Key dates
| Filing date | Sep 13, 1989 |
| Grant date | Feb 12, 1991 |
| Priority date | — |
| Expiry date | Sep 13, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2101/15
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A three phase alternator is driven by a variable speed prime mover, and its rectified output is pulse width modulated by a gate controlled H-bridge power switch circuit. Predetermined pairs of power switches are gated on and off according to programmed duration and timing instructions contained in a read only memory. In a first embodiment, a sine wave output is produced by successive pulse trains. The first pulse train has alternating positive and negative constant amplitude pulses, with the widths of positive pulses varying sinusoidally and the widths of negative pulses being constant. The second pulse train has alternating positive and negative pulses of constant amplitude, with the pulse widths of the negative pulse components varying sinusoidally, and the pulse widths of the positive components being constant. The components of the first and second pulse trains have an energy distribution which corresponds to one cycle of a sine wave having a fixed frequency. The pulse width modulated waveform is filtered to produce a smooth, low distortion sine wave output waveform. In a second embodiment, the on and off states, and the duration and timing of the on and off states, are control…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.