Single-phase Grid Voltage Fundamental Frequency Research Articles

Single-Phase Grid Voltage Frequency Estimation Using Teager Energy Operator-Based Technique

This paper reports the performance of a technique for the estimation of single-phase grid voltage fundamental frequency under distorted grid conditions. The technique combines a Teager energy operator (TEO) with a frequency adaptive bandpass filter (BPF). The TEO is based on three consecutive samples and is used to estimate the fundamental frequency. The BPF relies on a recursive discrete Fourier transform (RDFT) and an inverse RDFT, and is used to extract the normalized amplitude of the grid voltage fundamental component. The technique is computationally efficient and can also reject the negative effects caused by dc offset and harmonics. It requires less computational effort, can provide faster estimation, and is also less affected by harmonics as compared with a technique relying on the RDFT-based decomposition of the single-phase system into orthogonal components. The performance of the technique is verified using both simulation and experimental results.

Power System Frequency Estimation by Using a Newton-Type Technique for Smart Meters

This paper proposes a single-phase grid voltage fundamental frequency estimation technique for smart meters. The technique relies on a nonlinear Newton-type algorithm and a recursive differentiation filter (NTA–DF). It can reject the negative effects caused by dc offset, harmonics, notches, and spikes. When compared with a NTA technique based on least-squares (NTA–LS), the proposed one reduces matrix dimensions, avoids matrix inversion, and is computationally efficient, thus requiring less hardware and associated cost for real-time implementation. Moreover, unlike the NTA–LS technique, the NTA–DF shows less sensitivity to the presence of harmonics. Simulation and experimental results are presented to verify the performance of the proposed technique.

Differentiation filter‐based technique for robust estimation of single‐phase grid voltage frequency under distorted conditions

This study proposes a robust estimation technique for the single-phase grid voltage fundamental frequency under grid disturbances. The technique relies on a demodulation method and a finite-impulse-response-based differentiation filter (DF). A frequency domain analysis for designing the DF is presented and is used to estimate the time-varying fundamental frequency from the instantaneous phase angle obtained by the demodulation method. The technique can reject the negative effects caused by the presence of DC offset and harmonics. The proposed DF shows less sensitivity to the presence of oscillations caused by the demodulation method when compared to a similar finite-impulse-response-based DF. Simulation and experimental results are provided to verify the performance of the proposed technique.