Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Accurate Calculation of RMS Value of Grid Voltage with Synchronization of Phase Angle of Sampled Data
Authors Do-Hyun Ham ; Soo-Bin Kim ; Seung-Ho Song ; Hyun-Young Lee
Page pp.381-388
ISSN 1229-2214
Keywords RMS value caculation ; Sampling points ; Synchronization ; Phase angle ; RMS value error ; ADCs sampling
Abstract A novel and simple algorithm for accurate calculation of RMS voltage is proposed in a digitally controlled grid-tie inverter system. Given that the actual frequency of grid voltage is continuously changing, the constant sampling frequency cannot be a multiple number of the fundamental frequency. Therefore, the RMS of grid voltage contains periodic oscillations due to the differences in the phase angle of sampled data during calculation. The proposed algorithm precisely calculates and updates the initial phase angle of the first sampled voltage in a half-cycle period using phase-locked loop, which is commonly utilized for phase angle detection in grid-tie inverter systems. The accuracy and dynamic performance of the proposed algorithm are compared with those of other algorithms through various simulations and experiments.