Improved Loss Modelling of SMC Components

From a manufacturing perspective, powdered metal has the potential to deliver cost effective manufacture for high volume parts in electric motors. Soft Magnetic Composite SMC is an iron powder that can be compressed into component parts. Each individual iron particle is magnetically isolated from its neighbours, preventing the flow of eddy currents which cause iron loss. The resulting component is isotropic, meaning it has the same magnetic properties in all directions. This gives the edge over conventional motor constructions, which are constrained to operate in two dimensions as they require the use of laminations to prevent eddy currents. The use of SMCs thus has the potential to offer cheap high performance electric motors compared to laminations.

Unfortunately, calculation of the exact iron loss associated with each SMC motor component is challenging as it is a function of the temperature, pressure and geometry used in the pressing process and the shape of the component itself. Data provided by SMC suppliers and used by machine designers to model losses are based on measurements of a single standard SMC ring. The result is that losses measured in real SMC machines can vary from those predicted using design software. Conventionally, expensive prototyping is an integral part of SMC motor development. This is a huge barrier to the widespread adoption of SMCs, as loss mechanisms in laminated machines is better understood.

In this project, academic loss modelling capability is combined with component pressing expertise in order to provide a flexible loss prediction method. This will allow motor designers to confidently design low loss high efficiency electrical machines and promote a dynamic UK supply chain with an improved time to market.