Saturation and armature reaction effects in surface-mount PMAC motors

Surface-mount permanent magnet synchronous motors are generally analyzed using cylindrical-rotor theory where saturation and armature reaction effects on inductance are usually neglected. However, in applications such as electric power steering systems where torque accuracy over a wide operating speed range is required, it becomes important to consider inductances along the direct and quadrature axes including their variation with load. This paper presents methods for determining these parameters by simulation and experiments