A detecting method for active-reactive-negative-sequence powers and its application

A simple but quite useful detecting method for the power of a three-phase circuit is proposed. The detected power is decomposed into four components of the fundamental power, i.e. active power, reactive power, and two components of negative-sequence power on the orthogonal coordinates. Based on these four components, the reverse calculations of the firing angles for the thyristors become simple and easy to implement. A typical application to the feedforward power control of a high-frequency (HF) cycloconverter is shown to prove the validity of this method