Mitigation of DC-Link Current Ripple for Cascaded Current-Source-Converters Energy Conversion Systems

In this paper, the optimized space vector modulation (SVM) strategy has been designed to reduce the DC-link current ripple in the cascaded current source converters (CSCs). The configuration of series CSCs is presented and a coordinated control scheme is applied for DC-link current regulation and achieving stable operation of the system. The key of DC-link current ripple mitigation is to design the pulse patterns of series current-source-rectifiers (CSRs) and series current-source-inverters (CSIs) collaboratively. Conventionally, the DC-link inductor is increased to reduce the current ripple. However, it will lead to bulky size, high cost, and slow dynamic response. Instead of that, this paper reveals that the DC-link current ripple can be significantly reduced by adjusting the pulse patterns of SVM between the cascaded CSRs and the CSIs. The simulation and experimental results verify the effectiveness of the proposed method.