Enhanced real time control of PWM inverters
US4994956A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1990 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Apr 25, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0022
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An inverter controller adjust a selected switching pattern to accommodate minor variations and loads in the neighborhood of that pattern. Pulse width modulated (PWM) patterns are determined for a range of loads and link ripple. For a pattern in use having A independent switching events, an A.times.B matrix is computed, where B is the number of controlled harmonics. The matrix elements represent sensitivity of controlled haromonics with respect to individual switching angles .theta..sub.i. The elements are ##EQU1## where n is the harmonic number of the controlled harmonic and .theta..sub.i is an independent switching angle. An unbalance vector comprised of the Fouier coefficient of the controlled harmonics in the inverter output is determined. This vector is a measure of the goodness of fit of a selected pattern for link ripple and load variation encountered with the selected pattern. The unbalance vector is compared to a threshold, and if the vector is less than the threshold, the switching pattern is used without modification. Otherwise, individual switching angle adjustments are calculated by dividing the unbalance vector by the sensitivity matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.