Permanent magnet synchronous motors (English name permanent magnet synchronous motor, referred PMSM): Summary: part of the permanent magnet synchronous motor: stator and permanent magnet rotor position sensors, electronic commutation switch. In order to achieve synchronous generator of energy conversion, the need to have a DC magnetic field generated by the magnetic field of the DC current, known as the excitation current of the generator. According to the excitation current supply mode, all available from other power generator excitation current, called him excited generator excitation power obtained from the generator itself is called self excited generator. Advantages: Permanent magnet synchronous motor has a simple structure, small size, light weight, low loss, high efficiency, high power factor advantages, mainly for applications requiring fast response, wide speed range, accurate positioning, high-performance servo drive system and DC motors the update replaces the motor.