Advanced Cooling Solutions for High-Frequency Medium-Voltage Planar Transformers

Statement of the Problem Being Addressed: High-frequency medium-voltage (MV) planar transformers can increase the efficiency of the power supply chain by directly stepping down the medium voltage (10s of kV’s) of the grid to low voltages (~100s of V’s) required by end users, such as direct current fast charging of electric vehicles. As with many power electronics, thermal management of planar magnetic transformers for MV applications presents a barrier to pushing the boundaries of high-power density, while maintaining high efficiency and reliability. Thermal management for MV planar transformers is further complicated by the need to maintain sufficient voltage isolation between the transformer and the environment typically resulting in increased thermal resistance. Statement of how this problem is being addressed: This SBIR program will develop a dielectric two-phase heat transfer device that will passively transport waste heat from the MV planar transformer to a heat sink. The form-factor of the device will be ideal of the planar geometry of the transformer and allow the device to be in close proximity to the heat source. The dielectric nature of the device will provide adequate voltage isolation between the transformer and the environment while providing a strong thermal link. What will be done in Phase I? The goal of the Phase I program is to develop a proof-of-concept prototype of the dielectric two-phase heat transfer device. This will include theoretical modeling, design for manufacturing and fabrication of the device. After fabrication, thermal and electrical testing will demonstrate the device’s ability to cool the MV planar transformer while providing sufficient voltage isolation. The Phase I will end with a theoretical design of MV planar transformer with enhanced thermal management. Commercial Applications and Other Benefits: Improved thermal management of planar transformers will push the boundaries of what is possible in terms of power density and efficiency. Thermally enhanced designs of MV planar transformers will be beneficial in the development of the nation’s electric vehicle fast charging infrastructure. Additionally, electric aircraft and spacecraft are increasingly using planar magnetic components due to their compact form and increased power density.