Power Magnetics for wireless car charging

June 30, 2016 // By Mauricio Esguerra, Magment UG
Magment is a new material, ideal to build large inductors. In contrast to metallic materials it is not manufactured with layered sheets; instead it is poured like concrete. This enables cost-efficient production, in particular in projects like charging during driving where the inductors are integrated into the road with charging power levels up to 100 kW. The efficiency depends widely on the size of the air gap, but in general it is better than with conventional materials.

The increasing demand for more and clean energy has led to a rising need for larger inductive components. This poses a challenge of providing magnetics optimized for cost, size and performance. The high demand has sparked the development of both improved magnetic materials (e.g., powder cores, amorphous), winding technologies (e.g., copper foil, flat wire) and optimized core geometries. This has yield a high refinement, pushing the limits of an otherwise conventional way of making inductive components. However, advancement in small steps maybe not enough to cope with the market expectations driven by the renewables revolution.

Magment power inductors and transformers are based on a disruptive technology for both a novel material and an innovative magnetic design. The material is a concrete with magnetisable grains embedded in a cement matrix manufactured in a pressureless process.

 

 

 

Fig. 2: DC-bias vs field strength (above) and specific core losses vs flux density

Its features are (Figs. 1 and 2):

  • Permeability in the same range as powder core materials
  • High DC-bias capability
  • Very low core losses
  • Very high thermal conductivity to efficiently dissipate heat
  • Concrete-like mechanical robustness in a very broad temperature range

These unique and outstanding properties allow the design of rugged inductive components with a distributed air gap for minimized winding losses by completely surrounding the coil by the MAGMENT material. This ensures a complete magnetic filling of the available volume within the housing yielding maximum performance and cooling. As compared to the conventional manufacturing of winding cores and sealing with a potting material, the flowability of our concrete materials allow a “wind and magnetic pour” process, which goes along with absolute shape and size flexibility. This allows to both tailor components to minimize material utilization and to any given space constraints by a special magnetic design algorithm yielding lowest cost as compared to any other inductive technology.

 

 

Fig. 3: MAGMENT inductor (above) depicting its inner magnetic material

Design category: