Integrated inductor for interleaved operation of two parallel three-phase voltage source converters

This paper presents an integrated inductor for two parallel interleaved Voltage Source Converters (VSCs). Interleaving of the carrier signals leads to improvement in the harmonic quality of the resultant output voltage and the line current filtering requirements can then be reduced. However, the instantaneous potential difference, caused by the interleaved carriers, may drive large circulating current between the parallel VSCs and an additional inductor is often placed in the circulating current path to suppress the current to an acceptable limit. Integration of both line filter inductor and circulating current filter inductor is proposed. The flux in the magnetic structure is analyzed and the values of the line filter inductance and circulating current filter inductance are derived. Steady-state and the transient performance of the system has been verified by means of simulation and experimental results.