New advances in soft magnetic materials - properties of moulded flux conductors in inductors and electrical motors

A new technology has emerged the last decade, based on a new group of materials; Soft Magnetic Composites (SMC), instead of laminated steel that facilitates production of products with more integrated, smaller, lighter, less costly and highly efficient electromagnetic machines. The application of this technology is a change of paradigm regarding integrated design and energy efficiency. This article describes a new group of SMC’s; Soft Magnetic Mouldable Composites (SM2C). With this material it is possible to produce electromagnetic components, using rotational- or gravital moulding technology, RotoCast. This new production method allows for integration of parts, coils etc, but also has a potential for automated low cost and high rate production. It is possible to reach impressive magnetic, mechanic and thermal properties in rotation moulded parts. High performance inductors and electrical motors has been produced by RotoCast and evaluated. The maximum permeability of SM2C is in the order of 30. This is ideal for inductors, since the storage of reactive energy is distributed uniformly. The total production cost of this type of inductors can be very low compared to conventional ferrite/litz solutions. Since the high frequency magnetization losses are low and the thermal conduction is considerable, there will be no hot-spots. For motors, the low permeability gives lower torque compared to conventional laminated motor structures. This is compensated by increasing the radius of the motor, and since the high-frequency magnetization losses are low the number of poles can be made very high, thus reducing the magnetic material giving the motor high torque-to-weight ratio