Motor rotor and IPM motor

An interior permanent magnet (IPM) motor comprising:

• an annular motor stator;
• and
• a motor rotor rotatably arranged inside the motor stator and including:
• an iron core, a mounting groove being recessed from an end surface of the iron core and extending in a direction from a middle of the iron core to an outer peripheral surface of the iron core;
• and
• a first magnet and a second magnet arranged at an interval along an extension direction of the mounting groove, the first magnet being fixed at a radial outer side of the second magnet, a magnetization direction of each of the first magnet and the second magnet being perpendicular to the extension direction of the mounting groove, and a coercive force of the first magnet being greater than a coercive force of the second magnet;
• wherein:
• a ratio of the coercive force of the first magnet to the coercive force of the second magnet is in a range from 1.2:1 to 2.6:1;
• a ratio of a length of the first magnet to a length of the second magnet is in a range from 1:4 to 1:8;
• and
• an included angle between adjacent surfaces of the first magnet and the second magnet is in a range from 7° to 15°.