Planar Magnetic Components in More Electric Aircraft: Review of Technology and Key Parameters for DC–DC Power Electronic Converter

Abstract

The More Electric Aircraft (MEA) has motivated aircraft manufacturers since few decades. Indeed, their investigations lead to the increase of electric power in airplanes. The challenge is to decrease the weight of embedded systems and therefore the fuel consumption. This is possible thanks to new efficient power electronic converters made of new components. As magnetic components represent a great proportion of their weight, planar components are an interesting solution to increase the power density of some switching mode power supplies. This paper presents the benefits and drawbacks of high frequency planar transformers in DC/DC converter, different models developed for their design and different issues in MEA context related to planar's specific geometry and technology.

Influence of Power Losses in the Inductor Core on Characteristics of Selected DC–DC Converters

“…Limit values of resistance R o , corresponding to transition between the range of CCM and DCM, were computed by means of the inequalities in Equations (12) and (15). Output voltage values were computed using the dependences in Equations (11) and (14) for CCM and DCM, respectively. The value of power losses (P R ) was computed using Equation (6).…”

“…Direct current (DC)-DC converters, which are used, e.g., in switch mode power supplies and semiconductor devices, also contain magnetic elements used to store electrical energy [1]. In recent years, more and more papers focused on modeling power losses in magnetic elements and on examining the influence of power losses in these elements on the characteristics of electronic equipment [1][2][3][4][5][6][7][8][9][10][11][12].…”

Magnetic Properties of Manganese-Zinc Soft Ferrite Ceramic for High Frequency Applications

“…The most common soft magnetic materials used in planar transformer cores are ferrites [4,5,6,7], a class of ceramics with the typical formula M 2+ Fe 3+ O 2− , where M 2+ represents a divalent metal ion or a combination of divalent metal ions (A + B), such as manganese-zinc (MnZn). In comparison to other materials, ferrites reveal several advantages: high resistivity, wide range of operating frequency, low losses, high permeability, temperature stability, versatile of core shapes, and cost-efficiency.…”

“…The value of B s is limited to the technologically breakthrough while the frequency of the signal might be increased by several MHz to insure an optimal value of applied voltage for the very small dimensions of the transformers. The most important advantages of such devices, when compared to classical transformers, are presented in literature [4,5,6,7], and they might be summarized as follows: low weight (15 g per 100 W), typical efficiency of ~97%–99%, small winding area, low profile that improves heat dissipation, and lower leakage inductance due to reduced/interleaved windings.…”

“…Planar transformers find their applications in numerous high-end electronics, where a high switching frequency is required while the allowed space is reduced, e.g., in telecommunications, medical instruments, automotive vehicles, defence systems, power conversion, and interference suppression [7]. The core of any planar transformer is made of soft magnetic materials, which are needed to be easily magnetized, yet they also fulfill a few other requirements: high permeability, high saturation flux density, and low core losses.…”