A Novel Three-Phase Current Source Rectifier With Delta-Type Input Connection to Reduce the Device Conduction Loss

Abstract— The three-phase current source rectifier (CSR) features a step-down ac–dc voltage conversion function, smaller ac filter size compared with the traditional two-level voltage source rectifier, and inrush current limiting capability. However, large conduction loss of semiconductor devices has limited the wide application of traditional CSRs. In this paper, a new CSR topology, delta-type current source rectifier (DCSR), is proposed to reduce the conduction loss. The proposed rectifier has delta-type connections on its ac input side and its dc-link current can be shared by multiple devices at a given time. This paper introduces the DCSR’s operation principle, modulation scheme, and design method. Based on the analysis, the conduction loss can be reduced by up to 20% with the proposed topology. An 8-kW prototype is then built to experimentally verify the performance of the DCSR. It has been applied as the active front-end in high-efficiency power supplies for telecommunication and data centers, where 480 or 380 V ac voltage is stepped down to 400-V dc voltage in a single conversion stage. It can also be used as the off-board dc fast charger for electric vehicles to increase efficiency. In high-power applications such as dc arc furnace and induction melting. < final year projects >