Flux Minimization in Interphase Coupled Inductors of Parallel-Connected Voltage Source Converters

A flux compensation technique is described to significantly lower the peak flux in interphase inductors used to suppress the flow of high-frequency circulating currents between interleaved voltage source converters (VSCs) operating with the discontinuous pulse width modulation scheme (DPWM). The technique described is useful to reduce the required cross-sectional area of interphase inductors, which reduces the size, weight, and material cost of the magnetics in interleaved VSCs. Coupled inductors (CIs) with cross-coupled windings are used to demonstrate the performance of the flux compensation technique using simulation and experimental results of an 11 kW (300V
dc
, 208V
ac
/31A) laboratory prototype. The inductor cross-coupled winding arrangement lowers the effective series inductance of the interphase inductors and makes it possible to produce high-frequency fundamental PWM output voltages with a very low voltage drop across the inductors.