Harmonic model of electronically controlled loads

The use of electronically controlled loads is the way used to improve the efficiency as well as the power factor of normal electric loads, obtaining thus energy efficient loads. This electronic control changes the load's global behavior resulting in a strongly nonlinear one, at this regards, the available models used to represent loads are not accurate enough, especially in the context of an iterative frequency domain harmonic penetration program/algorithm. In this article, the authors propose an extension of the crossed-frequency admittance matrix, in order to get a better representation of these electronic loads. The extension is done by adding another dimension to the matrix, the harmonic phase. The model is obtained using a programmable power source connected to a PC, and, by means of an acquisition board, one measures voltage and intensity. Due to the large number of tests needed, the authors have developed a software tool that automates the process giving, as a result, the load model. Therefore, the proposed model linearizes loads according to three variables: amplitude, frequency and phase of the harmonic with regard to the fundamental.