Development and Implementation of a Mouldable Soft Magnetic Composite

Electrical machines, chokes and induction heaters are found in most homes,
offices and factories all over the world. They are used to create movement, filtrate the power or to generate heat. A typical unit consist of a coil and a flux conductor material. Some of the materials have been established for over 100 years, while others are only a couple of decades old.

A new flux conductor material has been developed at the Division of Production and Materials Engineering at Lund University. The material is called soft magnetic mouldable composite (SM2C). This thesis is focused on investigating the potential of this material and lay a knowledge foundation, wherein the material properties and manufacturing process of the material is tested and further developed, as well as the material composition. In order to use the full potential of the material a holistic view of all the materials involved is necessary. Both coil and insulation suitable for the mouldable soft magnetic composite are therefore studied. Tests are performed both on the separate materials, but also together in applications. Several motors and induction heaters were built and tested in different projects.

Results from the work show that by changing from solid copper tubes to litz wire and by using a flux conductor an increase of efficiency from 50-80 % to 98 % is possible. This is due to lower losses in the current conductor and higher flux linkage.

The possibility to mould the soft magnetic composite has interesting potential. It is shown that sensors, current conductors and other soft magnetic materials can be integrated directly into the composite. Also, the technology will provide a good thermal contact between the materials. This is especially important for the current conductor, which is usually the main heat source. A good contact will help conduct away the heat if the device is designed properly.

Other opportunities are opened with the new technology as well. The size of a moulded part has no limit, unlike for other soft magnetic composites that are usually pressed. It is possible to mould parts into almost any geometry, but it is also easy to machine the material if wanted.