Motor Parameters and Operating Limits of PM Motor

Abstract

PM motors are attracting growing attention for a wide variety of industrial applications. So far as we know, the i_d=0 control method, in which a direct axis component of the armature current does not exist, is applied in general because of avoiding a demagnetization of the permanent magnet. The recent development of the permanent magnet materials, however, has brought magnets with large coercivity. Therefore, there is no need to be a slave to the i_d=0 control method. Several remarkable performance characteristics can be obtained by controlling the direct axis component of the armature current actively.
In this paper, the control method of armarture current is examined in order to obtain the maximum output in all speed range. The effects of the motor parameters and the rotor configulations are examined in detail and the optimum motor parameters to expand the operating limits are clarified.