A novel vector-locked loop scheme for synchronized extraction of harmonics

Abstract

The separation of the fundamental from a distorted waveform is an important component in the implementation of a custom power device. A novel scheme for a vector-locked loop (VLL) for synchronous extraction of harmonics/fundamental in a distorted periodic waveform is described here. An intuitive, though approximate, explanation is provided for the operation of the algorithm, focusing on the locking process and the filtering capability. Performance aspects are analysed and an approximate linear time-invariant model is presented to facilitate in the design. Moreover, a means for choosing design parameters to achieve the optimum performance is provided. Main features of the proposed VLL are its simplicity, excellent insensitivity to harmonics, noise rejection, availability of both fundamental and harmonics without additional processing, and the speed of operation. The claims are verified through extensive simulation studies in MATLAB®/Simulink®. © 2010 IEEE.