Control of Three-Phase Pulse Width Modulation Voltage Rectifier R.Guedouani 1 , B.Fiala 2 , E.M. Berkouk 3 , , M.S. Boucherit 4 (1,2,) Faculty of Electronic and Computer Department of Electrical Engineering University of Sciences and Technology ‘Houari Boumediene’ P.O. Box 32 El-Alia. Bab-Ezzouar, Algiers ALGERIA. (3, 4 ) Laboratoire de commande des Processus Ecole Nationale Polytechnique BP182, 10 avenue Hassen badi. El harrach, Algiers ALGERIA. Abstract: - In this paper, we develop an algorithm to control the input currents of three-phase voltage PWM rectifier in ABC frame. We start by elaborating knowledge and control models of this converter using Petri nets. Then, an algebraic modulation strategy using the triangular-sinusoidal with two carriers is presented. The digital simulation results show the performances of the network currents control with a unit power-factor. Key-Words: - Petri nets, PWM, Buck rectifier, Algebraic modulation, voltage control, Unity power factor, Network. 1 Introduction The power quality problem has interested many studies. Harmonics in transmission systems have attracted engineers attention even before the advent of thyristors [1]. In the modern power electronics era, the concern on harmonic problems is increasing. This is mainly spurred by the incessant proliferation of power electronic equipments as nonlinear loads, such as diode rectifiers. One of effective methodologies to handle harmonic problems is to use another electronic system. Among representative approaches are the active power filter and the PWM rectifiers. The latter is the approach of interest in this paper. A great amount of work has already been done concerning the three phases PWM boost rectifier and the buck rectifier [2-3]. The three-phase PWM buck converter, with six-step, provides adjustable DC output voltage and sinusoidal input currents with no low-frequency harmonics [4-5-6]. However, the switching frequency harmonics contained in the input currents must be eliminated by the input filter, which produces a phase shift between the line frequency components of the input currents and input voltages [4]. This paper presents a new control algorithm which provides output voltage regulation with line input currents and input voltages in phase. A control loop, designed by considering only output filter dynamics, is employed for output voltage regulation. The line input currents are controlled through control loop of input filter. This algorithm assures a unity power factor at the network side. In the following sections, a power stage topology of the converter, operating principle and control model are described. Then, a new algebraic PWM strategy for the three-phase source voltage rectifier is developed. A steady dynamic modelling and representative results of circuit simulations are presented. 2 Converter Modelling 2.1 Knowledge model A circuit diagram of the three-phase buck converter is shown in Fig. 1. The rectifier consists of six switches (diode - transistor) TDki commendable with the opening and closing, where the indices k=1, 2, 3 are the order of the phase and i = 1, 0 are respectively the upper and lower switches of the bridge. The two current sources are connected via a parallel capacitor. Practically, however, the available ac source is a voltage source; accordingly, the ac current must be a series combination of an ac voltage source and inductor (Fig.1). The LC network between the ac voltage source and the ac current source has a function Proceedings of the 6th WSEAS/IASME Int. Conf. on Electric Power Systems, High Voltages, Electric Machines, Tenerife, Spain, December 16-18, 2006 246