Common mode and differential mode circulating-current control in paralleled single-phase boost rectifiers

In this paper, the analysis of circulating currents of a paralleled single-phase boost rectifier system is presented. The DC loop and AC loop circulating currents are clearly explained. Based on the analysis of circulating currents, common mode circulating current (CMCC) and differential mode circulating current (DMCC) are clearly defined. Then, CMCC and DMCC compensators in a centralized control scheme are proposed to reduce the common-mode and differential-mode circulating currents in the parallel rectifier system. Finally, a prototype system is constructed and some experimental results are carried out to verify the validity of the proposed control scheme. From experimental results, the proposed control scheme can indeed reduce the circulating currents under different power rating condition in the parallel system.