Apparatus and method for eliminating variable offset values of current detecting signals
US6278255A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 2000 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | Feb 1, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M1/0009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus for eliminating variable offset values of current detecting signals and its method having a current detector for detecting feedback current from a three-phase AC motor and for converting the feedback current into voltage detecting signals containing offset elements, differential amplifiers for differentially operating a feedback analog offset signal and the voltage detecting signals, output amplifiers for amplifying the differentially operated voltage detecting signals to fit within the input range for controlling, an analog/digital converter for converting the amplified signals into digital signals, a control part for adding up the digital signals to a digital offset value and for comparing the digital offset value with a predetermined offset command and for applying a proportional plus integral function to the compared result and for outputting a digital offset signal of a pulse-width modulation waveform, and a digital/analog converter for converting the digital offset signal into the analog offset signal and for providing a feedback loop of the analog offset signal to the differential amplifiers. The disclosed invention can adjust a current detecting signal to a des…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.