Single-Phase Average Power Measurement Using Instantaneous Power Theory in a Fixed Point Processor

The Instantaneous Active and Reactive Power Theory or the p-q theory has many applications like control of active power filter, control of thyristor–controlled series capacitor, harmonic and reactive power detection and compensation etc. This paper presents a new technique of average power measurement in a single phase AC circuit using instantaneous power theory. The technique employs a simple algorithm using instantaneous power concept in α-β reference frame. The average power is then derived without employing any complicated calculation such as integration etc. The technique is applicable for sinusoidal and non-sinusoidal waveforms. The complete algorithm is validated via simulation in a digital PC and via experimentation, using an inexpensive mid-level 8-bit fixed-point processor.