Analysis of Current Controllers for Active Power Filters Using Selective Harmonic Compensation Schemes

This paper presents a frequency response analysis of current controllers based on selective harmonic compensation schemes for three-phase voltage-source shunt Active Power Filters (APFs). To perform this analysis, the time delay introduced by the inverter and the sampling is taken into account in the current controller closed loop transfer function. Doing this, the differences among the schemes are pointed out, demonstrating the importance and effectiveness of the delay compensation to maintain the whole system stability. In addition, the performance of each Current controller is evaluated by means of the total harmonic distortion of the mains line current and time response for fast load variations. The main goal is to identify the most suitable solution in terms of current controllers based on selective harmonic compensation for an industrial implementation. All the considered current control schemes have been tested on the same digital platform. Experimental results are presented for a 25-kVA shunt APF prototype compensating a nonlinear inductive load. (C) 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.