Ultra fast frequency independent instantaneous power factor detector

Abstract

Many schemes were attempted to lessenthe time taken for measuring thepower factor of a linear load. This paper suggests taking advantage of aprevious paper where only two samples of the voltage and current wereadequate to have a very fast calculation method of the power factor. Thatscheme used a phase locked loop (PLL) as a frequency multiplier scheme toacquire two progressive samples of the voltage and current which areconcurrent. The time elapsed for measurement was the reciprocal of the PLLsampling frequency; no further scheme was reported after that to claim afaster method. This paper gets use of that work to get two progressivesamples of voltage and current separated by a short time. The scheme isfrequency independent with an indication for lead lag. All the operations areexecuted by a PIC microcontroller rather than a computer with few supportcircuits. The output will be shown either in digital or analogue (DC) form.The percentage of error depends mainly on the resolution (number of bits)for both the ADC and DAC used.