Parameter Estimation of Single-Phase Rectifier-Based Loads: Analytical Approach

The recent rapid concentration increase of single-phase rectifier-based loads has led to the increasingly significant problem of current and voltage distortion in low-power electrical networks. To successfully perform a prediction of the current and voltage distortion in power systems due to such nonlinear loads, it is necessary to know the structure and model parameters of those power-electronics circuits. Generally speaking, since the structure of a typical single-phase rectifier-based load is rather known, the parameters of those loads remain to be determined. Concerning this matter, an algorithm for estimating the unknown parameters of a typical single-phase rectifier based load is presented in this paper. The algorithm is based on a general approach for determining analytically the waveform of the ac load current and the dc capacitor voltage within an arbitrary number of time periods. The described nonlinear load model along with the model parameters obtained by using the suggested estimation algorithm were verified by comparison against a laboratory-designed typical rectifier-based load. Excellent agreement between the estimated and measured load parameters, as well as between the measured and simulated current and voltage waveforms was found.