Friday morning, 28 June 2019
Advances in Planar Magnetics for High Frequency Switched Mode Power Supply
Prof. Ziwei Ouyang, Technical University of Denmark
Today, high efficiency and high power density converters are fundamental to the continued profitable growth of the telecommunications, automotive, aerospace and data processing industries. High-frequency operation can lead to a reduction in magnetics size and an increase in power density. The momentum towards high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic component structures.
Planar magnetics fabrication and assembly processes have several advantages over conventional magnetics:
· Low profile —planar magnetic components has a lower profile that their wire wound counterparts due to the fabrication process;
· Automation — based on advanced computer aided manufacturing techniques;
· High power densities — planar inductors and transformers are spread out and this gives them a bigger surface-to-volume ratio than conventional components, this enhances the thermal performance;
· Predictable parasitics —with planar magnetics, the windings are precise and consistent, yielding magnetic designs with highly controllable and predictable characteristic parameters
Planar magnetic components take advantage of microelectronic processing. In general the number of turns in planar device tends to be limited by the manufacturing process. The low profile tends to lead to a larger footprint compared with its conventional counterpart. Planar magnetic components are particularly suited to wireless power transfer because of their low profile. In multilayer devices the interlayer capacitance introduces resonance at high frequencies. This seminar covers the basic analytical model of planar structures based on impedance method, and also includes several design considerations such as high frequency winding resistance, high frequency leakage inductance, winding capacitance and magnetic core loss etc.