Reduced Sizing and Control of Shunt Active Power Filter for Rectifier-capacitor Fed Motor Drives using Conservative Power Theory

Most industrial motor loads driven by IGBT-based variable frequency drives typically employ six-pulse diode bridge rectifiers at the front end, followed by the bulky capacitor to smoothen the ripple. As this configuration behaves as a voltage source type of nonlinear load, its harmonic injection into the source becomes a vital problem. It is often mitigated using shunt active power filters (SAPF) with various control algorithms. Improperly designed shunt filters and associated passive components for this load type, demand a filter whose rating matches the load itself. This paper analyzes the optimal sizing of SAPF and involved passive components for a commercial rectifier-capacitive fed induction motor drive. Also, this paper proposes a systematic method to use one-cycle components from the conservative power theory (CPT) decomposition for the design stage of SAPF and later to control it. The proposed design and control effectiveness is verified using Matlab simulations, and results are presented.