Real-Time Power System Phasors and Harmonics Estimation Using a New Decoupled Recursive-Least-Squares Technique for DSP Implementation

This paper presents the mathematical basis to restructure the recursive-least-squares (RLS) technique for real-time implementations on digital signal processors (DSPs). The proposed decoupled RLS (DRLS) technique is adapted for real-time estimation of phasors and harmonics. The comparison between the proposed technique and the conventional RLS one shows considerable improvement in terms of reducing the turnaround time on two different off-the-shelf research and development DSP platforms. The DRLS technique also shows better computational efficiency than the adaptive linear combiner (ADALINE) and recursive discrete Fourier transform (RDFT) techniques in direct estimation of amplitude and phase angle when implemented on DSPs. The DRLS technique performance is also superior to that of the ADALINE and RDFT techniques under the presence of noise, subharmonics, and frequency variations. The performance of the proposed technique has been evaluated by simulations using MATLAB-Simulink and through real-time experiments. Selected results presented in this paper confirm the DSP turnaround time improvementand satisfactory performance of the proposed technique.