Practical application of the instantaneous power theory in the compensation of four-wire three-phase systems

For three-phase four-wire circuits, two compensation criteria are possible: one based on the instantaneous value concept and the other on the average value concept. Thus, according to the first method the noninstantaneous power current is reduced, without altering the instantaneous active power (time-instantaneous compensation, TIC). On the other one, according to the second method the nonactive current is reduced, without altering the average power (time-average compensation, TAC). When the zero-sequence voltage component exists, both compensation types, would not enable the zero-sequence (neutral) source current elimination. Then, two approaches are marked in this paper. The first one, is for eliminating the noninstantaneous power current or eliminating nonactive current component but neutral current can still flow. The second one for eliminating the modified noninstantaneous power current or the modified nonactive current, thus the neutral current components is compensated. Experimental results are obtained to confirm the theoretical properties and show the compensator performance.