Patent ID: 7923879

Claim:
A permanent magnet motor comprising: a rotor including a rotor core; and a plurality of permanent magnets provided inside the rotor core and establishing a plurality of magnetic poles, wherein the permanent magnets include a plurality of types of permanent magnets having different coercive forces; and said plurality of types of permanent magnets is disposed so that each one type constitutes one magnetic pole, wherein one or more of the permanent magnets having relatively smaller coercive forces have: a first magnetic characteristic that when a magnetizing field is caused to act on the permanent magnets from a point in a second quadrant in a hysteresis loop showing a relationship between magnetic polarization and field intensity, a magnetic susceptibility is substantially at 0 until reaching an inflection point thereof during magnetization, and when exceeding the inflection point of the magnetic susceptibility during the magnetization to the magnetization side, the magnetic susceptibility enters a loop approximating to the hysteresis loop in a first quadrant; and a second magnetic characteristic that when a demagnetizing magnetic field is caused to act on the permanent magnets from a point in the first quadrant in said hysteresis loop, a magnetic susceptibility is substantially at 0 until reaching an inflection point thereof during demagnetization, and when exceeding the inflection point of the magnetic susceptibility during the demagnetization to a demagnetization side, the magnetic susceptibility enters a loop approximating to the hysteresis loop in a second quadrant.