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A new definition of instantaneous active‐reactive current and power in three‐phase circuits, and its application
Author(s) -
Nabae Akira,
Yoshikawa Akira,
Cao Liyu,
Tanaka Toshihiko
Publication year - 1997
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/(sici)1520-6416(19971115)121:2<83::aid-eej10>3.0.co;2-v
Subject(s) - ac power , volt ampere , electronic circuit , current (fluid) , power (physics) , volt ampere reactive , compensation (psychology) , voltage , computer science , electrical engineering , electronic engineering , control theory (sociology) , power factor , voltage optimisation , engineering , constant power circuit , physics , psychology , control (management) , quantum mechanics , artificial intelligence , psychoanalysis
Conventionally, the active, reactive, and apparent power in three‐phase circuits has been defined by extending the concept based on the RMS values of voltage and current with respect to time in single‐phase circuits. Applying the definition based on single‐phase circuits to three‐phase systems with nonsinusoidal conditions has resulted in many options in the description of power properties, as well as their interpretation and compensation, and this has led to a controversy as to which method should be chosen, and how power quantities should be defined. This paper proposes a new definition of the instantaneous active‐reactive current and power based on instantaneous space vectors in polar coordinates for three‐phase circuits. The instantaneous active‐reactive power and current are defined in the voltage‐current vector plane without any special fictitious power. The new definition proposed here leads to the same formulas as the conventional ones, which is a great advantage of the new definition. Comparing it to the p ‐ q theory, we discuss the new definition in detail. It is shown that, using the new definition, one is able to calculate the instantaneous active‐reactive power and current directly from the voltage and current space vectors. The new definition thus offers a lucid concept of electric power in three‐phase circuits. Using digital simulation, an application example is shown to confirm the validity and practicability of the new definition. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 121(2): 83–91, 1997