Confluence of Integrated Magnetics and TCM for a ZVS Based Higher Order Differential-Mode Rectifier

Abstract

Two driving performance metrics in modern power-electronic systems are power density and efficiency: usually, improvement in one result in sacrificing the other. In this paper, triangular conduction mode (TCM) is used alongside integrated magnetics to achieve both performance metrics simultaneously. TCM is implemented by extending the switch current high enough to reverse direction and provide enough energy at the onset of the deadtime to discharge the parasitic capacitance of the SiC MOSFET. The elevated current ripple is alleviated by distributing the rectifier low-frequency current among parallel interleaved sub-modules. Taking advantage of the symmetrical topology of the differential mode Ćuk rectifier (DMCR), an integrated interleaved magnetic (IIM) structure is proposed to house all the inductors in a module. In doing so flux cancellation technique is used between the Ac-and Dc-side inductors to reduce the losses and size while using a custom core structure to control the flux coupling between the interleaved windings. A step by step design algorithm is presented to manage the different types of coupling within IIM. Challenges in design, fabrication, and testing of the system are analyzed and appropriate solutions are presented in each section. The solutions are supported by mathematical analysis to optimize the power stage design and validated by circuit as well as finite element simulations. An experimental setup is assembled to test this concept and multiple time-domain and parametric results are presented for proof of the concept in rectifier mode and single module mode.