Two-Phase, Dual Interleaved Buck-Boost DC-DC Converter for Automotive Applications

A two-phase buck-boost converter utilizing dual interleaving is presented in this article. The dual interleaving consists of an interphase transformer (IPT) that doubles the ripple frequency together with two conventional buck-boost switching arms, mitigating the inductor ripple current and aiding to increase the power density of the converter. A description of the design and selection of the power devices is presented for a 32-kW, 75-kHz dual interleaved SiC prototype with an IPT, such that a power density of 7.4 kW/kg is achieved. The operation of the circuit is verified experimentally using a prototype with 315-385 V supply range and 350-V output voltage, achieving 97.1% peak efficiency at 32 kW. The experiments reveal that the interleaved coupled currents are equalized without an active balancer.