Measuring of earth fault current
US8645087B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 2011 |
| Grant date | Feb 4, 2014 |
| Priority date | — |
| Expiry date | Sep 5, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M7/5395
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for measuring an earth fault current in an output circuit of an inverter (INU) operating on the PWM principle and forming alternating-current voltage from direct-current voltage, the output currents (iU, iV and iW) of which inverter are measured, and which inverter comprises at least two phase switches implemented with power semiconductor components (V1-V6, D1-D6), which switches, controlled by a control unit, connect their own output phases to a positive (+) pole and to a negative (−) pole of a direct-current voltage source such that the phase switches are repeatedly both in different positions and also in the same positions, wherein the results of current measurement during two opposite switch position combinations are recorded in memory, and the earth fault current is calculated by forming a difference of the measurement results of said combinations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.