Bidirectional DC/DC Converters in the Automotive Sector
Efficiency Increase through HF Litz Wires
In the automotive sector, bidirectional DC/DC converters are used to efficiently transfer energy between the high-voltage battery and auxiliary consumers. For modern vehicle architectures, a compact design with high power (e.g., 5 kW) and high switching frequency (200 kHz) is demanded practice to sustainably reduce weight and installation space.
The Challenge
Operation at high switching frequencies massively amplifies AC losses due to skin and proximity effects. This increases thermal stress and complicates EMC design. In addition, automotive-specific requirements such as extreme vibrations, temperatures exceeding 150 °C, and dynamic thermal cycles must be reliably met.
The pot core choke used forms the central HF component in the DC/DC converter and exemplifies the compact design made possible by the use of high-frequency-optimized RUPALIT® Safety litz wires.
The encapsulated winding with HF litz wire is designed for automotive requirements and ensures an insulation and protection concept for high switching frequencies, thermal stability, and mechanical resilience.
Support from PACK LitzWire
PACK LitzWire developed HF litz wires with ultra-fine individual wires (0.05 mm) for this application, which specifically minimize skin and proximity effects. Through optimized wire counts and defined stranding layers, uniform current distribution and a high fill factor are achieved. The insulation system with a specific triple foiling was precisely matched to the thermal, electrical, and mechanical requirements in the vehicle to simultaneously ensure maximum high-voltage resistance.
Result
Thanks to the customized HF litz wires, compact, highly efficient, and thermally robust DC/DC converters can be realized. The significantly reduced AC resistance leads to higher efficiency and improved thermal stability of the overall system under harsh automotive operating conditions.
RUPALIT® Safety
This VDE-certified structure sets new standards for safety in power electronics. Experience significant size reduction and accelerated winding processes by eliminating separate layer insulation.
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