A comparative evaluation of control strategies for current fed converters as filters for nonactive power in networks

The current fed dynamic compensator used for active filtering of distortion in power systems is characteristically unstable due to resonance between the filter capacitor and the supply inductance. This instability impairs the effectiveness of the compensator. A control technique used to eliminate the limit cycle, namely error modulation, is suggested and evaluated. The dynamic behavior of the dynamic compensator was also greatly improved by the implementation of a minor voltage feedback loop. This simple but effective alteration of the closed-loop transfer function of the dynamic compensator rendered the current fed dynamic compensator stable with good dynamic behavior. >