Permanent magnet synchronous motors (PMSMs) have been widely used in
many industrial applications. Due to their compactness and high torque density [1],
the PMSMs are particularly used in high-performance drive systems such as the
submarine propulsion. The permanent magnet synchronous motor eliminates the use
of slip rings for field excitation, resulting in low maintenance and low losses in the
rotor. The PMSMs have the high efficiency and are appropriate for high performance
drive systems such as CNC machines, robotic and automatic production systems in
the industry.