The outer flux barrier angle θob of the permanent magnet 130 is an angle between two straight lines connecting the farthest ends of the two flux barriers 125 and 128 provided at both ends of the permanent magnet 130 to the center C of the rotor 120. In other words, in FIG. 11, the outer flux barrier angle θob of the permanent magnet 130 refers to an angle between a first straight line L3 connecting the center C of the rotor 120 and the left end of the left flux barrier 125 provided at the first end 131 of the permanent magnet 130 and a second straight line L4 connecting the center C of the rotor 120 and the right end of the right flux barrier 128 provided at the second end 132 of the permanent magnet 130.
When the flux barriers 125, 126, 127, and 128 satisfy the above conditions, the flux barriers 125, 126, 127, and 128 are positioned in the open slot 116 of the stator 110. In FIG. 11, the inner flux barriers 126 and 127 are positioned at the open slots 116 of the stator 110. Therefore, the flux barriers 125, 126, 127, and 128 may reduce the leakage magnetic flux so as to alleviate the abrupt change of the magnetic flux and make the voltage induced in the motor 100 sinusoidal.
The angle θcp of the consequent pole 122 formed between two adjacent permanent magnets 130 among the plurality of permanent magnets 130 of the rotor 120 may satisfy the following formula.
θib/2<θcp<θob
