Analysis, design, and minimum phase selection of high power interleaved DC-DC converter

The primary use of interleaved bidirectional DC-DC converters (IBC) is for high current applications due to the inherent property of ripple cancellation, high redundancy, and improved efficiency. Proper analysis and design are required to improve the power density and reduce the cost of the N-phase IBC. Ripple current analysis plays a vital role in choosing the inductor and filter capacitors to minimize the size of an IBC. This paper presents the simple and generalized formulas for the current ripple minimization of N-phase IBC. Also, the inductor is designed with two different core materials, namely, Ferrite and Sendust. It is observed that the area product and weight of the magnetics have been reduced by 22% and 23%, respectively, for Sendust core in comparison with the Ferrite core. Furthermore, a discussion regarding the thermal analysis of IGBT modules to select an appropriate heat sink is stated. Moreover, the minimum phase selection has been proposed by considering several constraints such as area product of the core, discrete components size based on ripple analysis, cost of all components, and converter efficiency. The prototype of the selected minimum phase IBC has been developed and tested for a 7.5kW power level using TMS320F28335.