A Novel Power Measurement Method Using Lock-in Amplifiers with a Frequency-Locked Loop

In recent times, the global interest in climate control leads to the extensive use of renewable energy-based distributed power generation. These renewable energy systems contain grid-connected inverters (GCIs). In addition to the GCIs, an increase in the usage of electric vehicle chargers and non-linear load results in harmonic injection and frequency fluctuations in the grid system. This effect on power quality results in inaccurate and non-reliable power measurements using conventional methods. The inaccurate measurement causes complaints and inefficient planning to manage the supply and demand of power. To solve above mentioned problem, a novel method based on Lock-in Amplifier (LIA) and Lock-in Amplifier Frequency-Locked Loop (LIA-FLL) is proposed to measure accurate power under the condition of harmonics and frequency fluctuations. To validate the performance of the proposed power measurement method, the power measurement results are compared to the results of the classical method, fast Fourier transform (FFT), and ZERA COM 3003 (a power measurement reference instrument).