Within the last 20 years, the number of electric motors utilised in domestic, industrial and vehicle applications have increased drastically. About 70% of the electric power generated in industrialised countries is used in electric motors. The majority of this power is consumed by conventional fixed-speed motors, but a continuously increasing proportion is used by variable-speed motor drives as they can offer higher operating efficiency.
However, the high cost of variable-speed motor drives is the most important issue restricting wider application of such drives, which consists of the cost of the power electronics, control circuitry and electric motor. The cost of power electronics and controls has dropped dramatically over the last two decades, but the cost of the electric motor itself has only reduced incrementally. There are strong indications that SMC based innovative electric motor construction approach can significantly reduce the motor manufacturing cost and hence widen variable-speed motor drive applications.