Process and device for eliminating or reducing harmonics and/or resonance oscillations
US5235503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1991 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Dec 10, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An a.c. machine (7) with, connected in parallel thereto, a capacitor bank (CR, CS, CT), which are fed by a converter (1-4) with a d.c. intermediate circuit, form a resonant system which is excited by the rectangular current of an inverter (4) of the converter. In this case, there is superimposition of the fundamentals and the normal harmonics in the machine voltage and in the machine current of an additional harmonic with the frequency of the resonance point. In the lower speed range of the a.c. machine (7), this excitation is eliminated by an optimum operating sequence of current gaps, which are generated inside a current block by means of a quenching circuit (3). Current gaps are generated at the start and end of each current block for the purpose of damping the 11th and 13th harmonic, and in the middle of the current block for the purpose of damping the 7th harmonic. A turn-on angle basic value signal (.alpha..sub.M) is modified by a turn-on angle differential signal (.DELTA..alpha..sub.M) for the purpose of damping the 5th harmonic, in particular an exciting or available harmonic being controlled to 0 or in the vicinity of 0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.