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.

Keywords

• inorganic coils design
• high frequency equivalent circuit
• voltage spikes in stator coils
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