An Integrated Inductor for Parallel Interleaved VSCs and PWM Schemes for Flux Minimization

The interleaving of the carrier signals of the parallel voltage-source converters can reduce the harmonic content in the resultant switched output voltages. As a result, the size of the line filter inductor can be reduced. However, in addition to the line filter, an inductive filter is often required to suppress the circulating current. The size of the system can be reduced by integrating these two inductors in a single magnetic component. An integrated inductor, which combines the functionality of both the line filter inductor and the circulating current filter inductor, is presented. The pulsewidth modulation (PWM) schemes to reduce the flux in some parts of the integrated inductor are also analyzed. The flux reduction achieved by using these schemes is demonstrated by comparing these schemes with the conventional space vector modulation and the 60° clamped discontinuous PWM scheme. The impact of these PWM schemes on the harmonic performance is also discussed. Simulation and experimental results are presented to validate the analysis.