FPGA-Based Instantaneous Estimation of Unbalance/Symmetrical Components through the Hilbert Transform

Asymmetrical loads in power systems leads to unbalance voltage/current signals and consequently, adverse effects such as overheating, lifetime, torque, and speed reduction, among others. In order to compensate the level of unbalance and avoid the above mentioned effects, the instantaneous unbalance and symmetrical components estimations have to be carried out. In this work, a methodology for estimating the instantaneous unbalance and symmetrical components through the Hilbert transform (HT) in three-phase voltage and current systems is proposed. First, a bandpass filter is used to remove the harmonics/interharmonics components; afterwards, the HT is applied to obtain the instantaneous amplitude and phase of each voltage/current signal. Finally, the symmetrical components and unbalance percentage are computed. The proposed approach is validated and tested through synthetic signals and under real operating conditions. Besides, a field programmable gate array (FPGA)-based implementation is developed as a low-cost and portable System-on-Chip (SoC) solution.