The <i>p‐q</i> 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.