A unified and simple model for uncontrolled rectifiers

A simple model for uncontrolled rectifiers with capacitive filter working in discontinuous current mode is developed in this paper. The presented model allows the rectifier ac line current harmonics to be obtained in an easy way. Previously, both the width and the peak value of the ac current pulse are calculated by means of analytical equations. This model is obtained when the rectifier working point is defined by dc current consumption or dc power consumption. In the first case, the expressions of the width and peak value are analytical, whereas in the second case they are non-linear; thus, an iterative algorithm is proposed to solve them. The rectifier behaviour is also graphically characterised in both cases from the previous equations normalisation. Several examples of the proposed model application are presented. Lastly, it is exposed that the model allows harmonic current emission to be studied in an easy, friendly way, according to the present regulations for both rectifiers.