Current source converter with switched-inductor DC link circuit for reduced converter losses

This paper presents a current-source converter (CSC) that uses a switched-inductor dc link circuit to improve its performance characteristics, providing opportunities to lower the conduction losses in the rectifier stage and dc link, as well as an additional degree of freedom for regulating the output current waveforms. The proposed topology replaces a single link inductor in the self-commutated CSC by a switched-inductor circuit consisting of a pair of inductors with two diodes. This type of dc link configuration takes advantage of the open-circuit state of the current-source rectifier stage to deliver double the nominal dc bus current to the inverter in order to boost the output current magnitude. Details of the circuit topology and modulation algorithm are presented, including closed-form expressions for the loss reduction as a function of the modulation index. Experimental results are provided to confirm the converter´s operating principles.