Referring to FIG. 13, there is no flux barrier at both ends of the permanent magnet 130 of the rotor 120′ unlike FIG. 11. Graphs in which the waveform of the voltage induced in the motor, the torque ripple, and the distortion rate of the counter electromotive force of the interior permanent magnet motor 100 having flux barriers 125, 126, 127, and 128 at both ends of the permanent magnets 130 as illustrated in FIG. 11 are compared with those of the interior permanent magnet motor 100′ having no flux barrier at both ends of the permanent magnets 130 as illustrated in FIG. 13 are illustrated in FIGS. 14, 15, and 16.

FIG. 14 is a graph illustrating the waveform of voltage induced in an interior permanent magnet motor according to an embodiment of the disclosure when a rotor of the motor has flux barriers and when the rotor of the motor has no flux barrier. In FIG. 14, the horizontal axis represents the rotor angle (degrees), and the vertical axis represents the voltage (V).

Referring to FIG. 14, in the case of the interior permanent magnet motor 100 having the rotor 120 provided with the flux barriers 125, 126, 127, and 128, the waveform of the voltage induced in the motor 100 is sinusoidal and bilaterally symmetrical. However, in the case of the interior permanent magnet motor 100′ having the rotor 120′ having no flux barrier, the waveform of the voltage induced in the motor 100′ is not bilaterally symmetrical.