Detection of Harmonics by using Parallel-Connected Nonlinear Limit Cycle Oscillators

Harmonic distortion in three-phase power systems has become a relevant problem and many research efforts are focused on the detection of harmonic components. Several existing tools have been reported in the literature to extract data from current and voltage signals and most of these tools are based on linear filters. However, non-linear tools have been barely used to detect harmonics. In this paper, a method to detect positive and negative sequence components of harmonics based on parallel-connected limit cycle oscillators is presented. The proposed method can be seamlessly applied for power system monitoring in order to extract harmonics of the fundamental frequency, even in the case of frequency fluctuations. In addition, it can be applied for harmonic diagnostic in three-phase electric machines. The performance of the proposed technique is validated through simulations performed in Matlab/Simulink. Results show that the proposed technique can be used to extract all the required details from harmonics in three-phase systems.