Integrated poly-phase power meter
US4924412A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 25, 1987 |
| Grant date | May 8, 1990 |
| Priority date | — |
| Expiry date | Jun 25, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R21/133
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A high accuracy power meter capable of measuring power supplied or consumed in multiple phases of a distribution system is fabricated as an integrated circuit. Voltage and current sensing transducers coupled to the power meter provide input signals having a potential proportional to the voltage and current in the distribution system. A low charge injection pulse width amplitude multiplier using a digitally-synthesized triangular wave is provided for each phase. Each multiplier receives the input signals and provides an output signal having a current proportional to the product of voltage and current in that phase of the distribution system. Charge from the multiplier output currents for all phases is accumulated in a capacitor connected across an autozeroing amplifier, which corrects for its own offset voltage. The amplifier output controls a switch connected between a reference potential and the capacitor. When the switch is closed, a reference current is supplied to the accumulating capacitor to balance the charge from the multiplier for each phase. The frequency of the switch control signal provides a highly accurate measure of the power consumed or supplied by the distribution …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.