In this paper a sensor-less speed controller for an Interior permanent magnet synchronous motor is presented. It allows to fully exploit the torque-speed characteristic of the motor, also in the flux-weakening region. It is based on the estimation of a generalized back-EMF space vector by means of a Luenberger state and disturbance observer. The estimated rotor-magnet position and speed are then employed inside an optimised vector control scheme of direct and quadrature motor currents trajectories. Test results are presented, in order to verify the performance and demonstrate the effectiveness of the proposed solution.
