PERMANENT MAGNET ROTARY ELECTRIC MACHINE AND PERMANENT MAGNET MOTOR DRIVE SYSTEM

摘要

A permanent magnet rotating electrical machine is capable of conducting a variable speed operation at high output in a wide range from low speed to high speed and improving efficiency and reliability in a wide operating range. Two kinds of permanent magnets 3 and 4 having different shapes or different magnetic characteristics are embedded in a rotor core 2, to form a magnetic pole 7. The permanent magnets arranged at the magnetic pole are the permanent magnet 3 whose product of coercive force and thickness along magnetizing direction is small and the permanent magnet 4 whose product of coercive force and thickness along magnetizing direction is large. A magnetic field created by passing a current to an armature coil 21 for a short time is used to irreversibly magnetize the permanent magnet whose product of coercive force and thickness along magnetizing direction is small, thereby changing a total linkage flux amount, and in addition, a positive d-axis current is passed when torque is large.