The invention discloses a structure of the rotor of a three-phase permanent-
magnet synchronous motor. The rotor is formed by
casting aluminium on a
silicon steel sheet axially slantwise in an overlaying way, wherein an
aluminium casting slot is punched on the outer circumference of the
silicon steel sheet, and an arc-shaped magnetic steel slot is punched in the
silicon steel sheet; rotor slantwise slots and an arc-shaped slantwise slots are formed on the rotor; the magnetic steel is arranged in each arc-shaped slantwise slot of the rotor; and the magnetic steel is made of the
adhesive rare-earth permanent-
magnet material and is in the shape of an inclined tile. Because the rotor slantwise slots are adopted, the magnetic vibration and the
noise are reduced greatly, the loss is reduced, and the efficiency is improved. When the magnetic steel in the shape of the inclined tile is arranged in the rotor slantwise slots, the fit clearance of the magnetic steel in the circumferential direction isolates
magnetism naturally, thus the strength of the punched sheet is improved effectively, and the rotor can be processed conveniently by adopting the mature asynchronous motor rotor aluminum
casting process. The three-phase permanent-
magnet synchronous motor is simple in structure, can operate stably and reliably, has high efficiency and a wide range of speed regulation and outputs at
constant torque. A simple and effective open-
loop control system with constant rotation speed requirements can be formed, and the cost spent constructing a
control system is saved.