Interleaved 3-phase PWM AC/DC converters based on a 4 switch topology

This paper deals with a detailed analysis of a unidirectional interleaved power converter for telecommunication systems typically with 3-phase, 220 V AC input and 10 kVA and 48 V DC output. To simplify the control system and to minimize the number of active switches used in the standard three-phase-three-pole and three-phase-four-pole topologies of PWM converter a new topology with 4 active switches is introduced. Along with the proposed topology some other available topologies with a reduced number of active switches are given. To improve the performance of the proposed topology and to eliminate the content of even harmonics in the supply current π/2 symmetry is introduced by interleaving basic units of a four switch converter. The interleaved converter consists of two diametrically opposite four-leg semi-converters. To eliminate the need of neutral conductor and to prevent the flow of triplen harmonics through the phase wires, a fourth wire (an artificial neutral point) is formed up locally using an R-L network. The fourth leg of each of the semi-converters is connected to this artificial neutral conductor. The interleaved converter has reduced cost, increased reliability, shoot though fault free legs and it is free from the problems of triplen and even harmonics. The proposed converter is tested for different steady state and transient operating conditions of the load