Characterization of a soft magnetic composite for use in road-embedded wireless-charging systems

The ferrite magnetic core is an integral component of road-embedded wireless charging systems for electric vehicles. However, the brittleness of ferrite makes it susceptible to premature fracture due to cyclic wheel loading from vehicles. This has motivated the development of a soft magnetic composite (SMC) composed of a flexible polyurethane and crushed ferrite as an alternative. An experimental investigation was conducted into the trade-offs between mechanical, thermal and magnetic properties at ferrite volume fractions between 45.9[Formula: see text]vol% and 80.6[Formula: see text]vol%. A comparison was made between measured properties and predictions from analytical models in order to further investigate the characteristics of the composite. The investigation showed a trade-off between the increase in magnetic permeability and the reduction in strain-to-failure as ferrite volume fraction increased. In addition, a large increase in flexural modulus and thermal conductivity, along with a slight increase in flexural strength was observed. More importantly, the strain-to-failure of the composite was 20 times higher than that of ferrite even at the highest volume fraction, indicating that the SMC was successful in providing a more ductile and flexible alternative.

Effect of the Temperature on the Magnetic and Energetic Properties of Soft Magnetic Composite Materials

In recent years, innovative magnetic materials have been introduced in the field of electrical machines. In the ambit of soft magnetic materials, laminated steels guarantee good robustness and high magnetic performance but, in some high-frequency applications, can be replaced by Soft Magnetic Composite (SMC) materials. SMC materials allow us to reduce the eddy currents and to design innovative 3D magnetic circuits. In general, SMCs are characterized at room temperature, but as electrical machines operate at high temperature (around 100 °C), an investigation analysis of the temperature effect has been carried out on these materials; in particular, three SMC samples with different binder percentages and process parameters have been considered for magnetic and energetic characterization.

A novel flux switching claw pole machine with soft magnetic composite cores

This paper proposes a novel flux switching claw pole machine (FSCPM) with soft magnetic composite (SMC) cores. The proposed FSCPM holds advantages of the conventional flux switching permanent magnet machine (FSPMM) and claw pole machine (CPM) with SMC cores. As permanent magnets are installed between the stator claw pole teeth, FSCPM has good flux concentrating ability, and the air gap flux density can be significantly improved. The torque coefficient of FSCPM is relatively high due to the applied claw pole teeth and global winding. FSCPM is mechanically robust because there are no windings or PMs on its rotor. Moreover, the core loss of FSCPM is relatively low for the SMC material has lower core loss at high frequency compared with silicon steels. The topology and operational principle of FSCPM are explained first. Several main dimensions of the machine are optimized to achieve better performance, based on 3D finite element method (FEM). Furthermore, the rotor skewing technology is adopted to reduce the cogging torque and torque ripple.