Instantaneous Reactive Power Theory: A Reference in the Nonlinear Loads Compensation

The instantaneous reactive power theory was published 25 years ago, in an IEEE Transactions. Since then, it has been the most used in nonlinear load compensation with active power filters. Its application allows constant source power to be obtained after compensation in a simple way. Moreover, some researches have showed up some limitations of the theory, i.e., it goes optimally with source voltage balanced and sinusoidal, but not so good with source voltage unbalanced and/or nonsinusoidal, since the source current obtained is not balanced and sinusoidal. This paper presents a new compensation strategy in phase coordinates, equivalent to the original theory´s one. Its simplicity, due to the nonnecessity of coordinate mathematical transformation, makes easier the modifications necessary to obtain alternative compensation objectives. In this way, this paper presents those modifications and derives compensation strategies that obtain alternative compensation objectives: unity power factor or balanced and sinusoidal source current. Finally, compensation strategies are applied to a practical power system, and the results are presented.