The reference active source current for active power filter in anunbalanced three-phase system via the method of instantaneous powertheory

摘要

This paper presents a method to generate the reference activesource current for active filter operating under unbalanced three-phasesinusoidal system using the instantaneous power theory. The conventionalapplication of the instantaneous power theory is effective in a balancedthree-phase sinusoidal system. However, in a practical systemthree-phase voltage unbalancing does generally exist. The proposedmethod uses the principle of geometrical similarity to process thezero-axis voltage and current into zero-sequence active current. Fromthe theoretical formulations, the proposed method obtains the sameresult as the equal resistance synchronous detection method. Thereference active source current is sinusoidal and in-phase to sourcevoltage, and can be directly calculated without 0-d-q axis conversion.From computer simulations and circuit implementations, both results aresatisfactory and have very good agreement