Coupled Inductor Design for Interleaved High-Current DC-DC Converters

Coupling inductors in interleaved DC-DC converters is known to reduce size of the converters magnetic components or to reduce losses. However, there are disadvantages such as a sophisticated inductor core design limits the use of this technique in many fields of application. Here, coupled inductors are employed in a high-current DC-DC converter consisting of multiple paralleled two-quadrant converters operated in interleaved mode providing 2.5 kA output current is designed and built. Aim of this work is to reduce the volume of the coupled inductors and simultaneously reduce the complexity of the magnetics. Though a coupled inductor structure can be very complex, a simple, cost-efficient implementation method has been found. This is a key to industrial use of coupled inductors. Results show that magnetic volume and winding volume are decreased compared to an uncoupled inductor reference design. Specifications regarding current ripple, core saturation, dissipated energy and robustness are met.