Patent ID: 8044548
Filing Date: 2011-10-25
Classification: H02K

Abstract:
1. A permanent-magnet-type rotating electrical machine comprising: a stator provided with a stator coil; and a rotor having a rotor core in which there are arranged a plurality of low-coercive-force permanent magnets and a plurality of high-coercive-force permanent magnets each coercive force is equal to or larger than twice that of each low-coercive-force permanent magnet, wherein each low-coercive-force permanent magnet is arranged in a radial direction of the rotor that agrees with a q-axis serving as an inter-polar center axis and is magnetized in a direction orthogonal to the radial direction, each high-coercive-force permanent magnet is arranged on the inner circumferential side of the rotor between two low-coercive-force permanent magnets to be oriented in a circumferential direction of the rotor and is magnetized in a direction orthogonal to the circumferential direction of the rotor, a diametrical section of the rotor is shaped so that the low- and high-coercive-force permanent magnets surround a part of the rotor core serving as a magnetic pole portion, and a flux density or both a flux density and a magnetizing direction of each low-coercive-force permanent magnet is irreversibly adjusted by passing a pulse current to the stator coil for a short time, an amount of the pulse current being adequate to form a magnetic field that is sufficient to irreversibly change the flux density or both the flux density and the magnetizing direction of each low-coercive-force permanent magnet while no magnetization that may cause irreversible demagnetization occurs on each high-coercive-force permanent magnet.