Ultra fast frequency independent instantaneous power factor detector

Abstract

<p>Many schemes were attempted to lessenthe time taken for measuring the<br />power factor of a linear load. This paper suggests taking advantage of a<br />previous paper where only two samples of the voltage and current were<br />adequate to have a very fast calculation method of the power factor. That<br />scheme used a phase locked loop (PLL) as a frequency multiplier scheme to<br />acquire two progressive samples of the voltage and current which are<br />concurrent. The time elapsed for measurement was the reciprocal of the PLL<br />sampling frequency; no further scheme was reported after that to claim a<br />faster method. This paper gets use of that work to get two progressive<br />samples of voltage and current separated by a short time. The scheme is<br />frequency independent with an indication for lead lag. All the operations are<br />executed by a PIC microcontroller rather than a computer with few support<br />circuits. The output will be shown either in digital or analogue (DC) form.<br />The percentage of error depends mainly on the resolution (number of bits)<br />for both the ADC and DAC used.</p>