A new approach for field weakening in a surface mounted permanent magnet synchronous motor by winding switching

In transport applications such as high-speed trains and hybrid machines, it is essential for motor to achieve speeds above nominal speed and operate in the field weakening region. A new approach to weaken the permanent magnet machine field is proposed in this paper. In this way, the three-phase stator winding of motor is divided into two parts, each part being connected to an inverter. This method is called the double winding switching technique, which can surely multiply the field weakening speed range of permanent magnetized motors. This research examines the stator windings connections, allowing the motor to work at normal and high speeds at constant output power.