New concepts of instantaneous active and reactive powers in electrical systems with generic loads

Abstract

This paper presents first a review of the conventional active and reactive power theory, valid for the steady-state analysis and them t h e instantaneous power theory, introduced by Akagi et a1 [ l , 21, is presented. This instantaneous theory is, valid for steady-and-transient states and for generic voltage and current waveforms. Some examples explaining the physical meaning of the new concepts will be presented. Also, by using the well known concepts of symmetrical components together with the new theory the powers in an unbalanced system will be analyzed, including the zero-sequence instantaneous power. It will be presented an example showing how this theory can be used to design and control an active power filter. Some simulation results a.re presented and discussed.

Single phase shunt active filter with digital control

“…In literature, several works can be found on control strategies for active power filters based on instantaneous power theory [3]- [5]. It can also be observed in literature, works involving control strategies for single-phase shunt active filters [6]- [8].…”

“…After the transformation, the p-q theory components are calculated using the expressions (3)(4), where p is the instantaneous real power, and q is the instantaneous imaginary power (by definition).…”

Power Flow in A Load-Current Sensorless Shunt Active Power Filter

“…It is expressed in terms of real power and imaginary power, which consist of an average value and an oscillating value. The relationship of these terms to the conventional concept about active, reactive and harmonic power can be seen in [5]. In this paper, power flow in the power system as well as in the shunt APF will be investigated.…”

Implementação de controladores para conversores trifásicos, sem transformações de coordenadas: análise geométrica através de vetores espaciais.

“…Neste item será discutida a influência destes harmônicos em p(t) e q(t). A interpretação geométrica apresentada nos itens anteriores facilita a compreensão da influência das diversas perturbações nas tensões e correntes, no comportamento de p(t) e q(t), sem a necessidade de cálculos algébricos como os apresentados por (Watanabe, et al, 1993).…”

“…Este processo já foi detalhadamente explicado por (AKAGI, et al, 2007) e (Watanabe, et al, 1993) , empregando os vetores no sistema αβ na notação vetorial e operações matriciais com as coordenadas dos vetores.…”