The p‐q theory in three‐phase systems under non‐sinusoidal conditions

The conventional theory of active and reactive power in single-phase or three-phase systems is based on an average value concept, thus making it impossible to define instantaneous active and reactive power in a real sense. On the basis of an instantaneous value concept, the authors have already proposed a new definition of instantaneous active and reactive power in three-phase circuits for arbitrary voltage and current waveforms without any restriction. This is called the instantaneous reactive power theory or the p-q theory, which is considered a basic theory of active power line conditioners such as reactive power compensators and active power filters for harmonic compensation