Three-phase dual-buck inverter utilizing coupled inductors

Dual-buck circuit has higher reliability as it overcomes the straight-leg problem existing in the traditional bridge circuit. However, more magnetic components are needed in this topology, especially in three-phase dual buck inverter. Magnetic integration is a good way to reduce the volume and weight of the magnetic components and improve the density of the system. The coupled-inductor dual-buck circuit utilizing PCDC (partly coupling with dotted-ends connected) method is essentially identical to three-inductor dual-buck circuit, which separates the anti-through and filter inductors and improves the inductor utilization compared to the conventional dual-buck circuit. This paper proposes an optimal design method for the coupled inductors. It not only decreases the magnetics number, but also reduces the total volume in comparison with discrete three inductors. The comparison of volume as well as equivalent filter inductance is carried out to verify the better performance of the coupled inductors. Finally the theory is validated by a 15kVA prototype, the experiment results are in consistent with analysis.