Method and apparatus for metering and monitoring ac generators

Abstract

This invention involves transducing and monitoring the power being delivered by an electric generator to a power bus by using a monitor which includes an embedded microprocessor in the memory of which are stored reference digital numbers that correspond to the generator's nominal power, and to the components of the nominal power including output power. The generator's voltage and current signals are sensed and then shaped for use by the microprocessor wherein they are digitized into a first set of digital numbers. Preferably, the first set of digital numbers is converted into pulse-width modulated (PWM) square-wave signals, which are demodulated into DC current signals that are indicative of the power and the components of power being delivered by the electric generator to its power bus. The microprocessor digitizes the square wave signals into a second set of digital numbers, and calculates from the first and from the second sets of digital numbers real time digital numbers. Preferably a microcontroller is also embedded with the microprocessor to compare the calculated real time digital numbers with their corresponding reference digital numbers and to generate control signals to selectively actuate circuit breakers which interconnect the generator and its loads to the power bus.