Novel sensorless permanent magnet synchronous motor and rotor position judgment method

The invention relates to a novel sensorless permanent magnet synchronous motor. The motor comprises a rotor and a stator sleeved outside the rotor, wherein the rotor comprises rotor magnetic steel anda plurality of permanent magnets arranged on the rotor magnetic steel, and the plurality of permanent magnets are arranged along the circumferential edge of the rotor; the stator is provided with a winding, and the rotor is provided with a plurality of salient poles used for assisting in generating non-uniform inductance; the plurality of salient poles are arranged along the circumferential direction of the rotor, and the salient poles and the permanent magnets are alternately arranged. The position-free control can be realized only by slightly changing the radial height of a rotor magnetic steel boss, so the manufacturing process is simple, and the automatic batch production is easy to realize. The use of an encoder can be avoided, and the production and manufacturing cost of the motor system is greatly reduced.