This paper presents the design of a compact high-efficiency motor drive, in which power density and efficiency are optimized by a high-voltage high rotation-speed innovative machine design, while still relying on a low-voltage battery (60 V) as the main power source. The required voltage inversion and amplitude boost are jointly achieved by means of a fully WBG-based Y-Inverter: GaN devices are used on the primary (low-voltage) side and SiC transistors on the output (higher-voltage) side. The switching frequency of the primary and secondary side switches are set independently for best efficiency and electro-magnetic signature. So, the study focuses specifically on the design of magnetic components enabling such dual frequency operation, while at the same time contributing to reduce the current stress in semiconductors and capacitors, by means of cross-coupled inductance power cell interleaving. Technological choices for future hardware development are also discussed, for both the semiconductor devices and the passive components.