Iron loss in PM brushless AC machines under maximum torque per ampere and flux weakening control

Summary form only given. Permanent magnet brushless AC machines employed in applications such as electric vehicles and spindle drives are operated under both constant torque and constant power modes. However, whilst the influence of machine parameters on the operational characteristics has been researched extensively, relatively little has been reported on the influence of the control strategy and motor topology on the iron loss. Most investigations consider only the no-load iron loss. However, the iron loss requires careful consideration, particularly under high-speed, flux weakening control. The paper investigates the airgap flux density distribution, the flux density loci in the stator core, and the associated iron loss in two brushless AC motor topologies, having a surface-mounted magnet rotor and an interior-mounted magnet rotor, respectively, when operated under maximum torque per ampere control in the constant torque mode and maximum power control in the flux-weakening mode.