Permanent magnet electrical rotating machine, wind power generating system, and a method of magnetizing a permanent magnet

An electrical rotating machine having a rotor and a stator, wherein:

• a plurality of permanent magnet sets are disposed in a rotor iron core of the rotor along an outer periphery of the rotor iron core to face an inner periphery of the stator with each permanent magnet set provided for each pole so that polarities of the permanent magnet sets change alternately;
• a plurality of cooling airflow channels are formed on an outer surface of the rotor iron core of the rotor, with each cooling airflow channel provided between a pair of adjacent opposite poles along the outer periphery of the rotor iron core of the rotor, to extend from the outer surface, in a radial direction, to a radial center of the rotor iron core so as to promote airflow and cool the permanent magnet rotor during rotation;
• and
• each cooling airflow channel is configured with a mouth portion at the outer surface of the rotor iron core, and a stem portion extending from the mouth portion, in the radial direction, to the radial center of the rotor iron core.