Design of inorganic coils for high temperature electrical machines

Abstract

The paper deals with a high frequency model of inorganic coils used to build high temperature (HT∘) motor. The HT∘ wire has a nickel layer that protects the copper against oxidation and a thin inorganic coating, which has poor electrical and mechanical properties. Therefore, the coils must be designed with a special care for getting a good distribution of turn-to-turn voltage during the fast transients excited by the steep fronted voltages of the PWM inverter.A specific coil structure is proposed and a high frequency (HF) equivalent circuit able to compute the turn-to-turn voltages during transients. The voltage distribution between the coils of a stator phase is also detailed.

Comparative study of permanent magnet synchronous machine vs salient pole synchronous machine in high temperature application

“…Organic insulation using Polyamide Imide (PAI) and Polyester Imide (PEI) material does not allow to exceed 200°C at the hottest point of the machine (the conducting copper). To go beyond this limit, inorganic insulation can be an alternative solution [8][9] [10], like ceramic copper wire, nickel-plated copper wire, or anodized aluminum tape. However, the mechanical characteristic of inorganic insulation is different than this of PEI-PAI; what requires specific know-how in winding and machine building, which can bring real manufacturing difficulties.…”