Flux-weakening control of surface mounted PM synchronous motors accounting for resistive voltage drop

This paper deals with the flux-weakening control of surface mounted permanent magnet synchronous motors, taking into account the influence of the resistive voltage drop in the stator windings, an effect which is usually neglected in similar studies. At first, the motor equations exploiting the optimal torque-speed limits in the flux-weakening region are evaluated and discussed. Then, the influence of the resistive voltage drop is pointed out, evidencing the mismatches related to its neglecting in the set-up of the flux-weakening strategy. Hence, a simplified approach to flux-weakening motor control is presented, useful for the practical implementation in micro-controlled drives. Finally, experimental results are shown, using a position-tracking application as a test case.