Frequency domain modeling of nonlinear loads, considering harmonic interaction

Large-scale penetration of power electronic-based loads is a concern in modern distribution networks due to the increase in harmonic distortion. Harmonic analysis in frequency-domain is suitable to deal with this problem due to the high computational efficiency. This type of analysis relies on the accuracy of nonlinear load models. This paper presents the development of a coupled admittance matrix model, able to characterize the interaction between harmonic voltages and currents, for a single-phase rectifier. The model was obtained by carrying out simulations in Matlab/Simulink. The dependence of the admittances on the phase angles of the harmonic voltages is considered by means of the tensor representation of the matrix. Besides, the effect of the variation of voltage distortion magnitude is analyzed. One thousand cases with different voltage distortions were carried out to test the model. The validation is achieved by comparing the aforementioned results with the respective simulations in time-domain.