A new approach to individual-phase reactive power compensator for nonsinusoidal and unbalanced three-phase systems-proposal for a quasi-instantaneous reactive power compensator

This paper discusses the merits and demerits of the already proposed instantaneous reactive power compensator in three-phase systems, and proposes a new approach to an individual-phase reactive power compensator, which the authors named the “quasi-instantaneous” reactive power compensator. A new definition of active and reactive currents in single-phase circuits is derived using window integral, and its physical meanings are discussed. The “quasi-instantaneous” reactive power compensator is constructed using the new definition. It compensates individual-phase reactive currents quasi-instantaneously. Digital simulation is used to demonstrate the validity of the novel reactive power compensator. In particular, the authors show that the power factor of each phase become unity on the source side, but the source currents remain unbalanced when the proposed quasi-instantaneous reactive power compensation method is applied