AC to DC conversion system with current spreading circuit
US4523266A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 14, 1983 |
| Grant date | Jun 11, 1985 |
| Priority date | — |
| Expiry date | Feb 14, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/01
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power supply circuit having a higher power factor and decreased current crest factor. The circuit preferably comprises an input circuit for receiving an input AC voltage and rectifying this voltage and an output circuit for providing a DC output voltage. A pulse-width-modulation circuit intercouples between the input and output circuits and includes a controlled circuit adapted to pass input AC current in pulse-wide increments with the pulse-width varying in inverse proportion to the AC voltage. In this manner, when the instantaneous AC voltage is low, the pulse widths are wider and conversely when the voltage is high, the pulse widths are narrower. In one version of the invention, the pulse width modulation is carried out by a programmed variable ratio transformer. In one preferred embodiment of the present invention, the current spreading circuit is of a quasi cosecant type while in another preferred embodiment of the invention, there is a combination of pulse-width-modulation with a typical input filter circuit including an OR circuit at the output to provide the necessary combining.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.