ABSTRACT
The motors are designed such that its terminal voltage reaches the maximum source voltage when it operates at the base speed with the rated torque. The Permanent magnet synchronous motors (PMSM) speed range is divided into two with a base speed as the pivot: The low-speed range from zero to the base speed is called the constant torque region, while the high-speed range above it is called the field-weakening region or the constant power speed region. In the constant torque region, the performance is limited only by the allowable maximum current, since the back EMF is not high enough to hit the voltage limit. To achieve a high torque density, motors are designed to use the achievable maximum electric and magnetic loadings. A high-speed motor along with a reduction gear offers a reduced volume. Due to this smaller volume merit, there is a tendency to utilize high-speed motors in electric vehicles (EVs).
